Observing and Photographing the 2017 Total Solar Eclipse

On Monday August 21, 2017, the heavens will declare the glory of physics as the Moon passes in front of the Sun creating a total solar eclipse. The Moon will block out the incredibly bright light of the surface of the Sun, revealing one of the most amazing sights in all of nature - the delicate and subtle solar corona, the Sun's outer atmosphere. The Moon will appear as a black disk in the center of the corona, a vision that has been described as "the Eye of God."

Multiple-exposure composite sequence of the 1991 total solar eclipse.

About the Eclipse

The solar corona is about 1 million times fainter than the Sun's photosphere, its normally visible surface. This is why the corona is normally invisible - it is lost in the blinding glare of the Sun's brilliance. But during totality, the Moon covers up all of the Sun's photosphere, and the corona becomes visible. The corona is about as bright as the full Moon and is safe to look when the Sun is completely covered by the Moon.

Just as you see your shadow on the ground on a clear sunny day because your body is blocking the Sun's light, the Moon casts a shadow when it blocks the Sun's light. It is this shadow of the Moon that you are standing in during a total solar eclipse.

The Path of Totality

This shadow, called the "umbra", is very small where it lands on the face of the Earth. For this eclipse, it is only 60 to 70 miles wide. To see a total eclipse you have to be located in the "path of totality" where the umbra falls. If you are just outside of this path, you will not see a total eclipse at all, you will only see a partial eclipse. You may think "how much of a difference could that make?" Well, all of the difference in the world. The difference between saying "shrug," and screaming "OH MY GOD!"

Here is the first critical thing you need to know - you absolutely must be within the path of totality to see the corona, prominences and chromosphere. Xavier Jubier's 2017 Eclipse Path of Totality Google Map overlay with local circumstances is the perfect tool to find a place to see the eclipse in the path of totality.

Totality lasts the longest on the "centerline" of the eclipse, a line that runs along the exact center of the path of totality. As you move towards the edges of the path of totality, the length of totality is less. For example, totality lasts 2m 38s in Lanthrop, north of Kansas City, MO. In North Kansas City, it lasts 1m 5s. In Kansas City, in the middle of the intersection of West 16th Street and Central Street, in front of the Kauffman Center for the Performing Arts, totality lasts just 5.7 seconds. If you are standing on the sidewalk in front of the west end of the Performing Arts Center, you will not see any totality at all.

You must be within the path of totality for the August 21, 2017 solar eclipse to see the real show. Note that totality for this eclipse only lasts from 2 minutes on the west coast, to about 2 minutes and 41 seconds at maximum near Carbondale, Illinois, and about 2 minutes and 30 seconds when it crosses the east coast. Click on the image above to see a larger version of the map. Copyright Michael Zeiler www.GreatAmericanEclipse.com.

This is an example of Xavier Jubier's 2017 Eclipse Path of Totality Google Map overlay for Casper Wyoming, with the local circumstances for the eclipse. Clicking on a location in the path will bring up local circumstances, such as the exact time of the eclipse given in coordinated universal time. You will need to convert UT to local time by subtracting 7 hours to get Pacific Daylight Time (PDT), 6 hours for Mountain Daylight Time (MDT), 5 hours for Central Daylight Time (CDT) and 4 hours for Eastern Daylight Time (EDT).

Weather

To see the August 21, 2017 total eclipse of the Sun you will need a clear sky. And you know what they say about the weather. Basically, you pay your money and you take your chances.

But, with a little research and planning, you can greatly increase your chances of clear skies. Jay Anderson has excellent weather projections on his Eclipsophile web site for the entire United States. That's why we decided to go to Madras, Oregon, on the eastern side of the Cascade mountain range, which as some of the best weather prospects in the country.

Jay Anderson's map of annual afternoon cloudiness derived from observations from NASA's Aqua satellite. Darker shades of blue indicate less cloudiness. Darker shades of brown indicate more cloudiness.

Oregon weather from NASA's Moderate Imaging Spectroradiometer (MODIS) from Jay Anderson showing the average August precipitation (1981-2010). Heavier precipitation is shown in green. We can see that there is considerable precipitation, and associated cloudiness, on the Oregon coast and Cascade mountain range. Moist air from the Pacific ocean dries as it precipitates out over the Cascades leading to drier conditions in the Columbia basin. Basically, darker orange/brown areas are where you want to be. Data from the PRISM Climate Group, Oregon State University.

Cloud Graph from MODIS from Jay Anderson showing average cloud cover along the central axis of the eclipse based on observations from satellites over a 15-17 year period. Lower points on the graph line have the best weather prospects. Click on the graph for a larger version. Data from NASA/GSFC.

Of course, these are climate predictions based on long term observations. Unfortunately, as anyone who has ever listened to a weather forecast knows, just like predictions of presidential elections, weather predictions can be wrong. Climate is what you get in the long term. Weather, however, is what you get on a daily basis. The two are not the same thing.

It is very possible for a big weather system to come in off the Pacific Ocean and make it over the Cascade mountains, and for it to be cloudy for the eclipse in Madras, despite the best laid plans of mice and men.

The way to deal with weather, no matter where you observe from, is to be ready to run to clear skies.

Check the weather forecast a couple of days in advance for a general idea of what is predicted. Have alternative observing sites picked out.

One day before, look at the forecast and make a decision as to where you will try to observe the eclipse.

6 hours before, check the forecast and satellite cloud maps. You may have to run to clear skies at the last minute.

Forest Fires and Smoke

Smoke from forest fires can also cause serious problems in trying to observe the eclipse.

Satellite photo showing wildfire smoke in the southern United States in 2016.

Keep an eye out for forest fires and check the following links to help you decide where to observe from.

Traffic

General Preparations

Find an site within the "path of totality" to observe the total solar eclipse.

Get a safe visual solar filter.

Make a check list for equipment that you plan to bring.

Make a check list for clothes, medicine, supplies, and other things you may need. Bring lots of water and Sun protection since this is in the hottest part of the summer.

If you plan to photograph the eclipse, make an exposure plan.

Practice with your photographic setup on the Sun (filtered) and Full Moon (unfiltered).

Make a list of things that you want to visually observe during the eclipse.

Make a list of things that you want to photograph during the eclipse.

Evaluate the weather: 24 hours before totality 12 hours before totality 6 hours before totality



Local Circumstances

Make a list of the local circumstances for your planned observing site so you will know exactly when the eclipse and, most importantly, totality start and end.

For example, the local circumstances for Madras, Oregon, a prime viewing site because of excellent weather prospects, are given below.

Madras Oregon Local Circumstances

Latitude: 44° 38' 0.6" N

Longitude: 121° 7' 46.2" W

Elevation: 754.5m (2,475ft)

Local time: 420 min (7 hours) behind UT

Duration of eclipse: 2h 34m 21.3s

Duration of Totality: 2m 04.2s

Path width : 100.7km (62.6mi)

Umbral vel. : 1.010km/s (2,260 mph)

Phenomenon Time UT Local PDT Alt Az Eclipse Begins 16:06:40.9 09:06:40 a.m. 29.4 102.9 Totality Begins 17:19:31.7 10:19:31 a.m. 41.5 119.1 Maximum Eclipse 17:20:32.7 10:20:33 a.m. 41.6 119.4 Totality Ends 17:21:35.9 10:21:36 a.m. 41.8 119.6 Eclipse Ends 18:41:02.1 11:41:02 a.m. 52.4 143.8

Visually Observing the Eclipse

Giant red prominences and the inner corona are seen along the limb of the Sun during the total solar eclipse of 1991.

Here are the things to look for, and take pictures of, during a total solar eclipse - if you are in the path of totality. If you are not in the path, you can forget about all of these things except the partial phases.

Safe Solar Filters

Warning! It is extremely important that you use a safe solar filter to view partial phases of the eclipse, or you risk permanent blindness! NEVER LOOK A THE SUN WITHOUT A PROPER SAFE SOLAR FILTER! Whether with your naked eye, through binoculars, through a telescope, or any other way. You must use a safe solar filter! During totality when the Moon completely covers the Sun, it is safe to take the filter off and look at the Sun and its corona in all its magnificent glory. It's even ok to look with binoculars without filters during totality. As soon as totality ends though and the Sun reappears, it is very important to replace your solar filters.

Phases of the Eclipse

The eclipse is divided into two main parts - the partial phases and the total phase.

Partial Phases - The Moon covers only part of the Sun leaving it looking like a crescent that gets thinner as the eclipse progresses until the Moon completely covers the Sun and totality begins. At the end of totality the Sun will begin to peak back out and it will again look like a very thin crescent which will gradually get larger as the Moon moves away from the Sun. The partial phases before and after totality last more than an hour. You must use a safe solar filter to view the Sun during the partial phases!

Total Phase - The Sun's photosphere is totally covered by the Moon. This is where the real show is. The total phase of this eclipse will last between about 2 minutes and 2 minutes and 41 seconds depending on your location. Take your filters off for totality - it is safe to look at the Sun now. Be prepared and don't miss totality! When totality ends be sure to put your solar filters back on.

The times for these events are given as "contact" times for when the limbs of the Sun and Moon meet:

C1 - First contact. The eclipse starts when the Moon first begins to cover the Sun.

C2 - Second contact. Totality starts when the Moon completely covers the Sun.

C3 - Third contact. Totality ends when the surface of the Sun reappears.

C4 - Fourth contact. The eclipse ends when the entire disk of the Sun is visible again.

What to Look For

Partial phases - be sure to use a safe solar filter!

Solar crescents.

Quality of light changes.

Temperature changes.

Animal behavior.

Horizon darkening from the Moon's approaching shadow.

Shadow Bands before 2nd contact.

Baily's Beads at 2nd contact.

The Diamond Ring at 2nd contact.

Red prominences just after 2nd contact.

The red Chromosphere just after 2nd contact.

Look for Corona detail in binoculars (no filter during totality).

Locally it will be about as bright as full moon during totality.

Look for horizon colors during totality - "360° sunset".

Look for Earthshine during mid-totality both naked eye and with binoculars.

The Sun will be in the constellation of Leo. Look for nearby planets and stars during totality: Regulus 1° to the left of the Sun (East of the Sun). Mars 8° WNW of the Sun at mag 1.8. Mercury 10° SE of the Sun at mag 3.3. Venus 35° to the W of the Sun at mag -4. Jupiter 51° to the SE of the Sun at mag -1.8.

Look for red Prominences just before 3rd contact.

Look for the red Chromosphere just before 3rd contact.

Look for Baily's Beads at 3rd contact.

Look for Diamond Ring at 3rd contact.

Look for Shadow Bands just after 3rd contact.

Look for departing shadow if you can stop screaming and jumping up and down.

Partial Phase of the Solar Eclipse - The Sun is not completely covered by the Moon and a safe solar filter must be used for observing.

Partial Phases - The Moon will begin to cover the face of the Sun. As it moves across more and more of the Sun will be covered up, leaving the Sun looking like a crescent. If you have binoculars or a telescope (both with safe solar filters) look for Sunspots on the surface of the Sun when the edge of the Moon covers them up. If the seeing is good, and you have a telescope, look for mountains in silhouette on the edge of the Moon. The surface of the Sun that you see here is the Photosphere, which means "sphere of light." Here solar gasses become opaque, which make up the visible surface seen in white light. The Photosphere's temperature is about 5,700° K. If the seeing is good you may also see detail in the umbra and penumbra of Sunspots through a telescope at high power.

Solar Crescents - When the Sun shines through small holes, such as the spaces between leaves on trees, it will project an image of the Sun on the ground. During the partial phases, these projections will look like tiny crescents which get thinner as totality approaches. It can be fun to make your own small holes in a piece of cardboard to spell out something like "Eclipse 2017!"

Quality of Light - the "quality" of the light will change dramatically as the eclipse progresses. It will get very harsh nearing totality because the Sun is becoming more of a point source.

Temperature Changes - The temperature will drop and it will cool off as the Sun is progressively covered up. After totality the temperature will rise as the Sun is uncovered.

Animal Behavior - As the Sun is covered up and the sky goes into deep twilight along the path of totality, animals may start acting strange. They are not expecting nighttime in the middle of the day. Roosters may even crow. If you have animals nearby, check out their behavior. Humans, of course, may go temporarily even more insane than they normally are - from joy during totality.

Horizon Darkening - Look for the western horizon getting dark. The Moon's shadow will move basically from west to east. If you have any local geographic features, such as mountains to the west of you, keep an eye out for a dramatic darkening as the shadow approaches your location just before totality. The shadow will be moving at about 2,000 miles per hour!

Shadow Bands - Shadow bands are a subtle feature that can sometimes be seen in the minute or so just before totality. These undulating waves can be seen on smooth light-colored surfaces, like a white sheet spread on the ground or the hood of a white car. They are thought to be caused by the point-source nature of the light from the extremely thin crescent of Sun not totally covered up by the Moon with rays of sunlight shimmering as they pass through the Earth's atmosphere. This is similar to why the stars twinkle at night, or why you see waves rippling on the bottom of a pool in sunlight. Because they are moving, and are such a low-contrast feature, they are hard to photograph but they may be easier to record in a video, so keep your cell phone handy. Look for them about 30 seconds before C2 and after C3.

Baily's Beads - As the eastern edge of the Sun is finally covered by the Moon, the last bits of sunlight shine through valleys between mountains on the limb of the Moon, causing tiny dots of sunlight called "Baily's Beads," named after English Astronomer Francis Baily, who first described them during the 1836 total solar eclipse. When the last Baily's bead disappears, it is safe to remove your solar filters and enjoy the full splendor of the totality unfiltered. The reappearance of Baily's Beads on the western limb of the Sun signals the end of totality and when you should replace your solar filters.

Diamond Ring - As the very last Baily's Bead shines through a valley on the moon the inner corona becomes visible and looks like a ring around the Moon with this bead shining like a diamond.

The diamond ring just before second contact at the 1991 Total Solar Eclipse.

Prominences - These are bright red clouds of hot glowing plasma gas that shine in the red light of hydrogen alpha. They may appear as jets, loops and arcs on edge of the Sun and are best seen on the western limb just after totality begins. If the Sun is quiet, as is usual during this minimum phase of the solar cycle, they may be small and you may need binoculars or a telescope to see them. But if we are lucky there may be one or more large prominences that can be seen by the naked eye.

Chromosphere - The chromosphere is the middle layer of the Sun's atmosphere. It also shines in the red light of hydrogen gas heated to more than 36,000° Fahrenheit. It is a thin 1,200-mile thick layer sandwiched above the Sun's photosphere and below the corona. Chromosphere literally means "sphere of color." Prominences arise out of the chromosphere when hot jets of super-heated gas shoot out due to the explosive release of the magnetic energy of the Sun. The prominences and chromosphere will only be visible for about 6 seconds at the start and end of totality.

Solar Corona - the corona is the outer atmosphere of the Sun. It can only be see visually during a total eclipse of the Sun. It is one of the rarest and most beautiful sights in nature and seeing it may be a once-in-lifetime experience. The corona extends millions of miles into space and is made up of super-heated plasma at about 2 million degrees K. The light from the visible corona comes from three sources:

The K (Kontinuierlich) Corona is closest to the limb of the Sun and is made up of sunlight scattered by free electrons. The Fraunhofer lines of the photospheric spectrum are smeared out so that the spectrum of the K corona is almost a pure continuum. The K-corona is the brightest part of the visible corona out to 1.5 solar radii.

The F (Fraunhofer) Corona is comprised of sunlight scatter by, or reflected off, dust particles and actually merges into the Zodiacal light. The F corona is the brightest part of the corona beyond 1.5 solar radii from the Sun's limb.

The E (Emission) Corona is made up of narrow spectral emission lines produced by ions in the hot plasma. The E-corona is much fainter than the K and F coronas.

Scientists list several other types of coronas which are generally only visible in the infrared:

The T (Thermal) Corona is caused by thermal emission in the infrared region by interplanetary dust.

The S (Sublimation) Corona is made up of the emission of low ionized atoms produced by sublimation of dust particles in relatively cold parts of the corona.

The Fl (fluorescence) Corona is caused by resonance fluorescence of molecules and free radicals produced by interactions of the K- and F-corona, solar wind and sunlight.

The IRF (Infrared fluorescence) Corona is caused by infrared fluorescence of silicon nanoparticles produced by interaction of the K- and F-corona and sunlight.

During totality, look for detail and streamers in the corona. The portion of the corona close to the limb of the Sun is as bright as the full Moon. The visual corona extends far from the Sun - its brightness gradually fading into the brightness of the sky background which is a deep, dark blue during totality. Depending on how transparent the sky is at your observing site, and how much haze, high clouds and aerosols and particulates, such as smoke from forest fires, are present, the visible solar corona can be seen up to 4-5 solar radii, perhaps more with binoculars.

Horizon colors - During totality take a quick peak around the horizon and look for colors like a 360° sunset.

Earthshine - During totality see if you can see any detail on the surface of the Moon lit by Earthshine. This is an extremely challenging observation because of all of the glare from the inner corona which is quite bright. Binoculars may help.

Stars and Planets - During totality the sky will be a dark twilight color. Take a quick peak and see if you can see Regulus just 1 degree to the east of the Sun. Venus should be easy to see shining at magnitude -4 about 35° to the west of the Sun. Jupiter will be 51° to the southeast of the sun at mag -1.8. Mars will be 8° WNW of the Sun at mag 1.8. Mercury 10° SE of the Sun at mag 3.3.

Towards the end of totality, events unfold in reverse order. Prominences will become visible on the western limb of the Sun, followed by the chromosphere, diamond ring and Baily's Beads. Solar filters should be replaced when the second diamond ring appears as once any part of the Sun's surface becomes visible, it is no longer safe to look at without proper safe solar filtration.

Just after totality ends you may be able to see shadow bands again and the departing shadow if you can stop celebrating.

Partial phases unfold in reverse order starting with a very thin crescent after totality ends.

Visual Observing Equipment List

Regular sunglasses

Eclipse solar-filter sunglasses

Binoculars

Binocular solar filters

Sun hat

Sun screen

Tape recorder

Bug spray

Chairs

Water

Cell Phone with GPS

Local circumstances list

Photographing the Eclipse

Totality lasts only about 2 minutes, to 2 minutes and 40 seconds, depending on your location. As anyone who has seen a total solar eclipse can tell you, there is a weird time dilation duality that happens. Time seems to stand still during totality, but it is over in the blink of an eye. Don't waste this precious time fiddling with a camera.

If this is your first eclipse, the best advice is to just observe the eclipse with your eyes and binoculars. Don't even try to take pictures. This is consistently the counsel that experienced veteran eclipse photographers give to first-timers. It really is great advice. Listen to it. To paraphrase Nike, "Just don't do it."

At most, have a camera hanging around your neck with it preset to automatic exposure, and maybe take one quick snapshot during totality.

It can be a lot of fun to have an audio recorder, say on your cell phone, going during totality. It will be a hoot to listen to later.

If you do decide to photograph the eclipse you will need:

The exact coordinates of your observing site. Find them with Xavier Jubier's Google Map Eclipse Overlay.

The exact contact times for your observing location. You can find those at Xavier Jubier's Local Circumstances Calculator.

A photographic game plan and backup plans.

Basic DSLR Camera Settings

Shoot Raw file format. If your camera can record Raw + JPEG that is ok, as long as your camera is also recording Raw.

Use your camera's highest native optical resolution. Look up your camera's resolution for Canon and Nikon cameras here under "Pixel Array". Go into your camera's settings and make sure it is set to the highest resolution. Read your camera manual to find out where this setting is located in the camera menus.

Use Daylight White Balance. You are shooting the Sun. That is where daylight comes from, so that's the white balance you want to use!

Turn off Auto ISO. Set your ISO manually. Low ISOs like ISO 200 will result in exposures that have the lowest noise.

Turn off Long Exposure Noise Reduction. The eclipse is not long enough to double your exposure times on long exposures for maximum corona.

Turn off the flash. It' won't reach the Sun. It won't even reach the Moon.

Use a tripod. Exposures will be long enough during totality that you will need one.

Prefocus on the edge of the Sun (with the solar filter in place) and tape the focus down. Don't forget to take your filter off during totality! Focus should not change with the filter off.

Turn off autofocus! This is very important. Your camera might not even fire if you have autofocus on and it can't detect a subject in focus.

Wide-Angle lens - Set your camera to autoexposure and ISO 200. Use a relatively wide aperture like f/4.

Telescope or long telephoto - Automate your exposure sequence in manual exposure mode with exposures in the eclipse exposure table below.

Use a remote release to open the shutter so you don't accidentally jostle the camera and make the images blurry.

There are a lot of other settings you can usually program in the camera menus. Most can be left to their defaults except the ones we just talked about above. Here are explanations for some of the other camera settings.

Photographic Game Plan

Be absolutely sure you shoot RAW file format in your camera. If you camera can shoot RAW plus JPEG concurrently, it is ok to shoot both, but be sure you are at least shooting RAW. RAW file format gives you a tremendous amount of latitude in processing.

Make a list of the pictures you want to take and put it on an index card that you can keep in your shirt pocket. For example:

Snapshots Wide-angle of your setup Wide-angle of the approaching shadow on mountains or clouds Eclipse crescents People looking through eclipse glasses Group picture of you and your friends





Eclipse Partial phases Diamond Ring and Baily's Beads Prominences and Chromosphere Corona



My philosophy for totality is to keep it simple. I recommend you keep it simple also.

Use only one camera with a lens, or camera shooting through a small telescope where the scope replaces the camera lens. Decide if you want to shoot wide angle or telephoto if you use a camera lens.

Automate your exposure capture sequence. Decide what software to use for automation. This will free you to visually observe the eclipse instead of worrying about trying to take pictures.

Photographic Filters

You will need a good safe solar filter both to view and photograph the partial phases of the eclipse.

Even after the eclipse starts, the Moon is not blocking out the entire photosphere of the Sun. The photosphere puts out so much light and radiation, it can blind you if you look directly at it, especially through binoculars or a telescope. Be careful!

It is only after the Moon completely block the Sun, and totality starts, that it is safe to take off your filters and look at the Sun with your naked eyes. You can look at the eclipse with binocular and a telescope without a filter ONLY during totality.

WARNING! Solar filters must be placed in front of the lens. That is where they will filter out most of the light before it reaches the objective of the lens or telescope. The lenses in a lens or telescope or binoculars gather light based on their aperture, or diameter. They gather and concentrate this light. That's why we use them to make faint things more visible and to magnify them. When you use these on the Sun, which is already incredibly dangerous to look at, you gather and magnify even more light, which makes it extremely dangerous. You have to filter out most of this light before it enters your lens or binoculars or telescope. You can NOT place any kind of filter behind the objective, say between the lens and camera, or telescope and eyepiece. It is extremely dangerous! Your solar filter belongs on the front end of the lens or telescope, facing the sky.

Some photographers are planning to use neutral density (ND) filters to photograph the partial phases of the eclipse. Some are even talking about stacking them to reach the required density to filter out the Sun. These may work, but stacking is a poor choice because all that extra glass will degrade the image and scatter light and possibly lead to reflections between the numerous glass surfaces. I would really recommend against trying to use a ND filter for photography. It is just to easy, and inexpensive, to get a safe solar filter with good optical quality, like the Baader AstroSolar Film.

Some other photographers may think they can use a polarizing filter to cut down on the intensity of the Sun's light. While polarizing filters may darken a normal scene to some extent, they are not going to come anywhere near enough reduction to use on the Sun.

WARNING! Almost all regular photographic neutral density filters and polarizing filters are NOT SAFE for VISUAL USE even if they seem to cut down the intensity of the Sun to a level usable for photography. This is because while they block a lot of visible light, they allow harmful radiation to pass through that is invisible. So if you try to use one of these for photography, which is not a good idea, you can NOT look through the camera while it is pointed at the Sun, even with the filter in place. Don't even try it!

Some solar filters are threaded to screw into the front of camera lenses. It is highly recommended not to use these for this total eclipse. Make sure your filter is easy to remove just before totality because the last thing you want to be doing 15 seconds before totality is struggling to remove a filter.

What Camera to Use

Camera - I will be using one of the following DSLR cameras, I have not decided yet as I am still testing the setup and weighing the benefits / drawbacks of each.

Canon T5i (700D) - This camera has more image noise but is much easier to focus and runs on Astro Photography Tool (APT) with a faster framing rate with a serial cable. Mirror lockup can be set to 1 second in APT camera control software.

Nikon D5300 - This camera has less noise, more dynamic range and is sharper because it doesn't have an anti-aliasing filter, but it doesn't run on APT. Mirror lock-up takes about 3 seconds to implement in BackyardNIKON (BYN) camera control software. This cuts down on the number of frames you can shoot during totality. And since this totality is not that long, this is an important consideration. But, the D5300 may have problems with flats.

What lens to use

Most photographers have a least the kit zoom lens that came with the camera. It is usually an 18-55mm f/3.5-5.6 zoom lens. This lens is great to use for wide-angle shots of the eclipse. You can even use it on auto-exposure during totality.

Some photographers may also have other lenses, usually another zoom lens with a longer focal length. These can be used also. With more focal length you can get a little more detail in the corona during totality.

In all cases, it is best to put your camera and lens on a tripod as exposures will get long during totality.

Using a wide-angle lens is the easiest way to photograph the eclipse.

If you want to zoom in and get a close-up of the Sun and Corona, you are going to need more focal length. At this point, things become more complex quickly as long focal lengths are slower and require longer exposures. They also magnify problems such as focus and image shake. These definitely need to be used on a tripod.

Wide-Angle Lenses

A more complex plan for a wide-angle is to shoot a multiple-exposure composite showing various partial phases before and after totality with a longer exposure of the corona in the middle. The partial phases are recorded with a safe solar filter over the lens. It is taken off for totality, and replaced when totality ends. These exposures through the filter will be very short like 1/1000th of a second at f/5.6 at ISO 100 with an solar filter with a density of ND5. Your exposure during totality with no filter will be relatively long, like 4 seconds at f/5.6 at ISO 800.

Multiple-exposure composite image by Ben Cooper, LaunchPhotography.com.

This kind of shot takes careful planning because you will need to know where the Sun is in the sky at C1, first contact at the start of the partial phases, and then where it will be at C4, at fourth contact at the end of the eclipse.

You will have to plan this out with a planetarium program set to the times of C1 and C4 to see how much the Sun will move in relation to the size of the field of view of your lens.

Ideally, you will want to have totality someplace interesting in the frame. This will depend on what else is in the frame. Remember the composition rule about not placing the main subject dead center. You can roughly aim your camera by knowing the Sun's altitude and azimuth at totality. Altitude tells how high above the horizon the Sun is. Azimuth gives a compass heading around the horizon where 0° is north, 90° is east, 180° is south and 270° is west.

Download a compass app and an inclinometer app for your smart phone. Then just line the camera up in altitude and azimuth with your phone.

To make your wide-angle shot something really special, have an interesting foreground at the bottom of the frame such as a majestic mountain, or even observers watching. Remember that whatever is in the foreground will be in the shadow of the Moon.

Shoot from a low angle so the foreground will be silhouetted against the sky. Meter and expose for the eclipsed sky with the filter off during totality for the foreground shot. This long exposure will also record the corona in your wide-field composite image.

When you frame your wide-angle composition, watch out for any street lights that might come on when the sky darkens during totality.

Partial phases will have to be shot with a safe solar filter over the front of the lens. Don't forget to take it off for totality! And don't forget to put it back on at the end of totality for the rest of the partial phases.

Telephoto or Telescope

If you have a long telephoto lens, say 200 mm or 300 mm, you can use that to shoot a close-up of the Sun to try to capture the Sun's corona during totality. A small refractor telescope with a focal length of 400 or 500 mm will work perfectly for this.

If you have a really fast lens, like a Nikon 180 mm f/2.8, or Canon 200 mm f/2.8, you might be able to get away with a 1 second exposure at f/2.8 at ISO 200 on a fixed tripod to capture the corona. The downside to using a lens like this on a fixed tripod is that you will have to aim the camera at the Sun just moments before totality to be sure it is centered in the frame. And your tripod has to be rock solid or your image will be blurry. The Sun will also be relatively small in the frame, even at 200mm, and even with an APS-C crop sensor.

Using a longer focal length will also increase the complexity of your setup greatly. For the long exposures during totality at a long focal length, you will need to have the lens or scope on an equatorial tracking mount to keep the Sun centered in the frame. The Sun and stars move across the sky faster than you probably realize at 15 degrees per hour, or 15 arcminutes per minute. That means the Sun, with an apparent diameter of 32 arcminutes, will move its own diameter in just 2 minutes, about the length of totality in the western United States. For an eclipse that lasts about 2.5 hours like this one from first to last contact, the Sun will move about 37 degrees across the sky.

I plan to use an Astro-Tech AT65Q as my imaging scope. It has 65mm of aperture, 420mm of focal length, and is f/6.5.

If you want nice close ups of any prominences, you need to be up over 1,000mm in focal length. Most experienced eclipse photographers agree that a telescope is superior to a lens at these focal lengths.

I did use a Nikkor 1,000mm f/11 catadioptric lens for the 1984 annular eclipse to shoot the prominences, chromosphere, Baily's Beads, and extreme inner corona on film and it worked well as seen in the image at right. But recently I tested a Nikkor 500mm f/8 in anticipation of using one for this eclipse, but I was disappointed in the results. The AT65Q was much sharper, perhaps because these lenses were designed back in the days of film photography and today's digital sensors can record much more resolution. Also, the 500mm f/8 Nikkor was incredibly difficult to focus, with just a couple of microns of movement throwing the focus off.

Tripod Stability, Mirror Lockup, and Camera Vibrations

Jupiter at 100% enlargement shot with a 400mm Lens at 1/15th second exposure. Jupiter is overexposed, but note the shapes of the Galilean moons. They look like fish hooks due to tripod instability. And this photo was taken on a really good tripod.



If you are going to use a telephoto lens, you need a good tripod. A really good, rock-solid tripod. Otherwise you may get blurry images due to camera movement when you touch the camera to open the shutter, or when the mirror flips up and the shutter opens. The image of Jupiter at right illustrates this, and it was shot on a really good $500 Gitzo tripod. This doesn't mean the tripod is not good in this case, it means that I was asking too much of it with long exposures through a 400mm lens. And I even used exposure delay in the camera which flips the mirror up for 2 seconds before the shutter opens.

You will also need to consider whether to use mirror lock-up to try to reduce vibrations in longer exposures. Even on a solid mounting the vibration caused by the mirror flipping up (Mirror Slap) and the shutter opening (Shutter Shock) can cause image blur.

The problem with mirror lock-up is that it takes a lot of valuable time, on the order of several seconds per frame. If you use it, it will cut down on the total number of frames you can shoot. On the other hand, if you don't use it, your images may be blurry and not useable at all, so it might not matter how many more you can shoot without mirror lock-up.

The only way you will find out is to take test exposures and practice! I recommend shooting your exposure series on something bright, like Jupiter right now, near the celestial equator at night. Shoot your series once without mirror lock-up and once with it turned on. Critically examine the images at high magnification in Photoshop to see if you need to use mirror lock-up. You might only need to use it on longer exposures.

Another possible consideration as far as stability during long exposures is wind. The wind can often pick up during an eclipse due to the drop in temperature as more of the Sun is covered. If your tripod or mount is rickety, the wind may affect the sharpness of long exposures.

The moral of this story is that for long focal lengths on a fixed tripod at shutter speeds longer than about 1/focal length (1/400th second for a 400mm lens), that tripod must be rock solid and you must use a remote release and mirror lockup to have any chance of success.

Framing

There is a "rule" for composition that says don't put the main subject dead center in the frame. If you are shooting a close-up of totality, this is going to be one of those times to break that rule.

Framing of the eclipsed Sun and corona will depend on the focal length of the lens or scope you use, the crop factor of your camera, and how much corona you want to try to capture. The corona actually extends out fairly far from the Sun, but it is difficult to capture in its full extent. The image overlays below will give you an idea of what to expect.

This is a realistic representation of what an amateur astrophotographer will probably be able to capture at the 2017 total solar eclipse with multiple exposures in an HDR composite. The corona, of course, will look different as it is unique to each eclipse. Fields of view at various focal lengths are seen for an APS-C sensor. This image shows the February 26, 1998 total solar eclipse from the island of Aruba in the Caribbean, taken by astrophotographer Andreas Gada who made an series of exposures ranging from 1/1000 of a second to 1 second in one stop increments at ISO 64 at f/6. The exposures were taken at 3 to 5 seconds intervals through a 5" f/6 Astro-Physics refractor. The exposure sequence was combined with masks and filters in Photoshop to produce this high-dynamic range image.

Corona up to 15 solar radii can be seen in Miloslav Druckmüller's image of the 2015 total solar eclipse from Svalbard. This image used exposures of 1/4,000th of a second to 4 seconds and was digitally composited and processed with special software to reveal detail in the full brightness range of the corona. Realistically, you are probably not going to have the technical skill to capture this much corona. Druckmüller is, literally, the best in the world at this. © 2015 Miloslav Druckmüller, Shadia Habbal, Peter Aniol, Pavel Štarha

Note that if you are shooting the eclipse with a long lens on a fixed tripod, the Sun will move it's own diameter in about 2 minutes. If you are shooting with 1,000mm on an APS-C sized sensor, you will have a field of view of about 76 arcminutes by 50 arcminutes. Since the Sun is 32 arcminutes in diameter, that means that you do not even have 2 solar diameters on the short side of the frame to play with.

When you set up with a fixed tripod, your natural inclination will be to orient the long side of the frame to the horizon. And this is ok, but you need to be aware of which way the Sun will drift through the frame if you don't re-center it during totality if you are using a long focal length.

You need to research the angle of the ecliptic at your observing site. This is the path the Sun will move along during the eclipse. You can usually find this pretty easy in a planetarium program. For most folks the Sun is going to be moving to the upper right more or less. So if you have a very tight field of view, you might be better off orienting your camera along the ecliptic instead of the horizon. The way, the Sun will stay in the frame longer.

Also, if you are shooting with a long focal length, and using long exposures to try to capture some long coronal streamers, you would be better off to orient the Sun so that its equator runs along the diagonal of your field of view. This will give the most room for the coronal streamers, which during solar minimum usually run along the Sun's equator.

The image at the top of this section by Andreas Gada has the solar equator and coronal streamers oriented along the diagonal of the frame.

Focusing

Live View

Use Live View with your DLSR to focus your camera for the eclipse. During partial phases you must have a safe solar filter in front of the lens or objective of your telescope.

Here's how to do it.

Put the filter on your lens or scope.

Center the Sun in the viewfinder.

Turn of Live View.

Magnify the Live View to 10x.

Focus on a Sunspot if there are any, or on the tip of the crescent of the partially eclipsed Sun.

Tape the focus down.

If you have an autofocus lens, turn off autofocus.

Consider refocusing just before totality because a drop in temperature can cause a change in focus with some long lenses and telescopes.

You should not need to refocus because you remove the filter as it is in front of the objective or lens.

If eclipse day is clear and bright, it may be hard to see the screen on your laptop or DSLR to critically focus. This is when a dark cloth comes in handy. Just drape it over your head and the LCD screen to block the sunlight. In the winter you could just use your coat, but being this eclipse will take place in the hottest part of the summer, you probably won't have your coat with you, so remember to bring something like a Mylar space blanket. They are small, lightweight and will do the job.

Dedicated solar photographers use a specially made view camera focusing cloth that is opaque with a reflective mylar side to block out the light and heat from the Sun, and a black side that goes inwards to stop any light that slips in from reflecting when the cloth is draped over your head and the business end of the scope where you would be focusing the camera.

You also need to be aware that there are two display methods that Canon and Nikon use for Live View:

Adjusted brightness - The camera automatically adjusts the brightness of the image to look correctly exposed on Live View, even if it will be incorrectly exposed at the manual exposure you have dialed in. This can cause real problems if you are focusing just before totality with the filter on, and all you have is a tiny sliver of the Sun surrounded by a gigantic black field. The camera will try to adjust the brightness of the Live View display to make the sky background a normal level of brightness and this will totally wash out the limb of the Sun that you need to focus on.

Exposure simulation - The camera sets the brightness of Live View based on the actual exposure you are using. This is the way you want to use Live View to focus.

Lower-end Canon models have exposure simulation automatically turned on, so if you have a camera like the Canon T5i (600D) you don't have to worry about this. Wither higher-end models like the 6D, you will have to go into the menus and turn on exposure simulation.

Nikons usually default to using adjusted brightness. For both cameras, you can do a simple test to see which way your live view is working. Just set the camera to manual with the correct exposure for the daytime scene. Then just dial the shutter speed up and down and see if the Live View displayed image gets darker and brighter. If it does, you are good. If the brightness stays the same, you will have to go into the menus and find this setting and change it. Read your camera manual well in advance of the eclipse to learn how to do this. Don't try to learn how to do it in the minutes before totality!

Software Assisted Metric Focusing

Programs like Astro Photography Tool, Eclipse Orchestrator, BackyardEOS, BackyardNikon and Images Plus Camera Control all have numerical readouts that can be used in Live View that will tell you when you have the best focus. These can work very well, but practice using them first. Full Width Half Maximum (FWHM) is a metric that is usually used with stars in deep-sky imaging and probably isn't going to work very well on the edge of the Sun. But these programs also offer other metrics like Standard Deviation that will work for the eclipse. Again, practice this well before eclipse day!

Autofocus

Usually you will have trouble autofocusing on the Sun during partial phases, because the Sun's surface doesn't have any contrast for autofocus to lock on to. With the filter on, there is nothing but the Sun on a black background. But you can give it a try. Here is a tip that might help:

Set your autofocus so that the camera will only use the central focus detector instead of the entire array of focus sensors available. Then try to put that central focus sensor directly on the eclipsed edge of the Sun and activate autofocus. You should be able to tell if it works. If it does, then tape down the focus and turn off autofocus.

Fixed Tripod

Normally during the daytime there is so much light your shutter speeds will be very short and you don't need a tripod.

But during totality, when the Moon completely covers the Sun and blocks almost all of its light, the foreground and scenery around you will only be illuminated by the light of the corona. The corona is brighter than you might think - it is as bright as the full Moon. But during totality the sky will be in twilight, and for a wide-angle shot, your exposures are going to be a couple of seconds long. You are not going to be able to hand hold that! You will need a tripod.

For longer focal lengths during totality, if you want to record any of the outer corona, your exposures are, again, going to be too long to hand hold. You will need a tripod.

Check out the exposure eclipse exposure table below to give you an idea of the exposures needed for your setup.

Eclipse Exposure and Blur on Fixed Tripod

If you plan on shooting the eclipse on a fixed tripod, you will have to contend with the Earth's rotation. Long exposures at long focal lengths will result in blurry images from trailing.

The Sun moves across the sky due to the Earth's rotation at a speed of about 15 arcseconds per arcsecond. It will move its own diameter (1/2 degree) in about 2 minutes.

How long of an exposure you can get away with before this becomes a problem depends on five things:

The focal length of your scope or lens. The pixel size in your camera. The declination of the object. The exposure length. Amount of acceptable blur.

For all practical purposes, we can ignore declination and just assume the worst case scenario here because the ecliptic is near the celestial equator where the declination error is maximum.

In my experience, I can shoot about a 1-second exposure at 180mm of focal length on a solid fixed tripod without trailing with a camera with 6.4 micron pixels.

For an 18mm wide-angle lens shot of the totally-eclipsed Sun in the beautiful deep blue twilight sky during totality , you can easily go several seconds with no problems, provided you are on a tripod.

With longer focal lengths, it gets a bit more complicated.

On a newer camera with 4.3 micron pixels, I shot a 1-second exposure that was a little bit trailed at 200mm.

Lets say we can use about a 1/2 second at 200mm with 4.3 micron pixels, or 1/4 second at 400mm.

Bill Kramer's "Do you really need a tracking mount?" calculator gives 1/4 second for 420mm and 4.3um pixels. This agrees with my real world experience.

So for the longest 6 to 10 second exposures for at f/6.3 for 420mm as derived from the eclipse exposure table below, I will definitely need to track on an equatorial mounting.

Roger Clark, however, says Exposure = (IS / 30) * 0.5 where IS is image scale, or about 2 arcsec/pixel for the 420mm and 4.3um pixels and 1/2 pixel blur. This works out to 1/30th second at 420mm or 1/15th second at 200mm.

Recently, Clark has apparently corrected his web page to now state that his formula for 1/2 pixel blur is simply Exposure = IS / 30. Which relaxes his standard by a factor of two. So, for a 420mm lens with 4.3um pixels, the image scale would be 2.11 arcsec/pixel we would get 2.11/30 = 0.07 seconds, which is roughly about 1/15 of a second, or 1/30th for 200.

Jupiter &@; 100%

Fixed Tripod

180mm Lens

1/2 second exposure

Use the Image Scale Calculator in the appendix if you want to know the image scale of your system.

That's 1/4 second exposure (me and Kramer) versus 1/15th second (Clark), or 2-stop difference with same scope and same pixel size.

So for super critical work at 2 arcsec/pixel with 1/2 pixel blur (essentially no blur), use 1/15th second from Clark. For real world, use 1/4 second or something in between the two for 400mm of focal length and a camera with 4.3 micron pixels or 1/2 second at about 200mm as seen in the image at right. Unfortunately, this short of an exposure is not going to record much corona at a low ISO. But you can shoot at a higher ISO and stack to improve the signal-to-noise ratio.

With a 180mm f/2.8 Nikkor, or 200mm f/2.8 Canon, you could shoot totality with a fixed tripod at 1/2 second at ISO 400 and stack 4 to 9 exposures and get the equivalent of a longer 2-3 second expsure with a lot of corona and Earthshine. In theory. The problems are the mirror lock-up delay between frames; changing the shutter speed; keeping the Sun centered in the frame during totality if you want to put together a high-dynamic range composite; movement due to tripod instability, mirror slap and shutter shock; and missing the eclipse by messing with your camera during totality.

A related problem in terms of image sharpness that many people don't realize they have is tripod instability and mirror slap and shutter shock. If you are going to use a lens more than about 100mm in focal length, your tripod must be as solid as a rock. A large rock.

Telescope Mount

For the long exposures needed with a long focal length during totality, you really need an equatorial mount.

A computerized altazimuth mount will keep the Sun centered in the frame, but will suffer from field rotation. An equatorial mount will keep the Sun centered without this problem.

If you are going to use, say, an 80-200mm zoom, or a 75-300mm zoom, You should consider mounting it on small equatorial tracking mount like an iOptron Skytracker, Sky-Watcher StarAdventurer, or Vixen Polaire so you don't have to constantly re-aim the lens to keep the Sun centered..

For larger scopes, a larger more serious equatorial mount is necessary.

Polar Aligning in the Daytime

Using an equatorial mount means it needs to be polar aligned, which is harder to do in the daytime.

Night - If you can set up the night before at your observing location, you can polar align in your normal manner with a polar alignment scope, or the drift method, or with a computerized polar aligning routine with a Go To mount.

Day - If you have to set up the morning of the eclipse in daylight, you can use a compass and inclinometer app in your smart phone to adjust the azimuth to aim it at true north, and adjust the altitude to the latitude of your observing location. You can also try to use the planetarium software in your smart phone to polar align your mount as outlined by Spencer R. Rackley IV. I could not get much accuracy with either my Android phone or my wife's iPhone with this method. I don't know if the phones are just not that accurate or if there was something magnetic on the mount. It's also possible to drift align your mount during the daytime using a sunspot if the Sun is within a couple of hours of the meridian. Pay attention only to north-south drift in declination. If the spot drifts to the north, the azimuth of your mount is too far west and must be rotated east. If the spot drifts to the south, the mount is too far to the east and must be rotated to the west. If the seeing is good enough for you to drift on the Sun when it is near the horizon, you can also do an altitude adjustment for your mount. If the spot drifts north, the altitude pointing of your mount is too high, it must be lowered. If the spot drifts south, the altitude is too low and must be raised. If you don't have a sunspot on the day of the eclipse, you can center the disk of the Sun on the cross hairs of a finder eyepiece or on the cross hair display on the LCD on the back of your DSLR camera.

Remember that true north is different than magnetic north. Look up the magnetic declination for your observing site for the offset and use it for polar aligning in the daytime.

High-Dynamic Range Imaging

With a longer focal length, say from about 300 mm up to 500 mm, you can try to capture detail in the corona. This will require high-dynamic range (HDR) techniques however as the brightness range of the corona is too large to be captured in a single exposure. In a long exposure to record the faintest outer streamers of the corona, you will overexpose the brighter inner corona and any chromosphere or prominences. Short exposures for the inner corona will not record any of the faint outer corona.

1/1,000th second 1/30th second 1 second

The three images by Andreas Gada seen above illustrate how different exposures capture detail in different parts of the corona. These are only three frames out of an 11 exposure series.

To shoot an HDR image showing detail in the full corona, you will need to shoot a series of exposures from very short to very long (see the eclipse exposure table below for your f/stop and ISO). These exposures are usually separated by about 1 f/stop in shutter speed. Then these exposures are digitally composited with masks in Photoshop, or with a special HDR program. Shooting an HDR composite is not a trivial undertaking.

High-Dynamic-Range (HDR) Image Compositing Programs

Extreme Imaging

If you are an experienced astrophotographer and want a challenge, try to record the maximum amount of corona and Earthshine on the Moon during totality.

Both of these phenomenon require long exposures on a correctly aligned equatorial mounting as well as some other considerations discussed below.

Maximum Corona To record the maximum amount of corona, you need a field of view that can take it all in. Miloslav Druckmüller has an image of the corona out to 20 solar radii shot with a full-frame Canon 5D and 200mm f/2.8 lens and exposures of 1/125th second to 8 seconds during the 2008 total eclipse of the Sun. Note the short focal length and full-frame camera needed to record this much corona. The F corona extends far out into the solar system, merging into the zodiacal light. This means that at a minimum, it will merge into the brightness of the sky background. As any deep-sky photographer knows, you can capture details fainter than the sky background by stacking exposures to increase the signal-to-noise ratio. But you usually need to stack quite a few exposures to be successful. The problem is that with a relatively short eclipse like this where totality is only about 2 to 2.6 minutes long, you don't have a lot of time to make a lot of long exposures. So we will try to take as many as we can, but realistically, we are probably not going to be able to record detail much fainter than the sky background. This means our longest exposures should try to correctly record the sky background, which can be roughly from about magnitude 13 to magnitude 16 using the same magnitude scale per square arcsecond as we do for the dark night sky. Magnitude 16 about how dark the sky is 45 minutes after sunset in the summer. How dark the sky will be during totality will depend on the elevation of your observing site and the quality of the air, including humidity, aerosols, smoke, haze or high clouds. Basically, we really don't know how dark the sky will be during totality unless we can get a pretty good guess at those influencing conditions. A good test for transparency is to hold your hand up and cover up the Sun with your thumb. See how bright / hazy the sky is next to the Sun. If you have blue sky all the way to the Sun, you have a very good transparent sky and it should get pretty dark. If you have a lot of haze or high clouds, the sky may be milky bright quite a distance from the Sun. You will need good transparency to record the maximum amount of faint corona. The exposure for a magnitude 16 sky is about 50 to 100 seconds at f/6.5 at mid histogram at ISO 200. Normally for faint deep-sky objects we only need to exposure to about 1/3 to 1/2 of this value to be read-noise limited which would be about 15 to 30 seconds at f/6.5 at ISO 200. My longest eclipse exposure will be 8 seconds, or 3 stops less for mag 16.2 sky, so the corners of the frame with just sky will be pretty dark, but not black. Unfortunately these exposures will not be long enough to record corona out to some crazy distance but it doesn't matter because at 420mm of focal length, which I plan to shoot at, I don't have enough field of view anyway. Note that transparency is not the same as seeing. Seeing describes the steadiness of the atmosphere. Good seeing is required for high-resolution detail, such as fine detail in sunspots or solar prominences. Good transparency is required for contrast between the faint outer corona and the sky background.





Earthshine Another challenge for technically-minded experienced total solar eclipse photographers is recording Earthshine on the Moon during totality. We are all probably familiar with the beautiful phenomenon of Earthshine when the Moon is a thin crescent. The Sun directly illuminates the lit portion of the crescent while the rest of the Moon is illuminated by Earthshine - sunlight reflected off the Earth and back to the "dark side" of the Moon. Earthshine This phenomenon of Earthshine can also be captured during totality if the air is transparent and you have an optical system with little scatter, and you use exposures that are long enough. Since the Moon will be centered in the middle of the much brighter inner corona, which is as bright as the full moon, we are faced with another high-dynamic range situation. The inner corona's exposure will be roughly 1/ISO at f/16 (say 1/100th second at f/16 at ISO 100), while the Earthshine will be roughly 1 second at f/2.8 at ISO 100. That is about 11.6 stops or about 3,265 times difference in brightness. What will happen is that in the long exposures required for the Earthshine, the inner corona will be overexposed and will bleed into the Earthshine. How much will depend on the transparency of the atmosphere and the scatter in your optics.

Scatter in your optical system is an important consideration in going for an extreme amount of corona and Earthshine. Lenses should be high-quality multi-coated. Optical systems such as a multi-coated oil-spaced triplet refractor will scatter less light than a camera lens with 18 optical elements. Optical systems should be well baffled and have clean surfaces that are free from dust which can scatter light. Test the scatter in your system by taking greatly over-exposed image of the full moon.

Eclipse Exposures

The exposures in the table below are in seconds for totality with no filter with the Sun reasonably high in a clear sky. Here is a printable PDF of this exposure table.

These exposures are for different eclipse phenomenon shot with a long telephoto lens or telescope. If you go down the line and use every exposure, as illustrated in the exposure sequence section, you can try to put together a high dynamic range composite image showing detail in all parts of the corona.

If you are shooting with a wide-angle lens, you can just shoot totality on automatic-exposure. Be sure to use a tripod.

Instructions:

Pick your ISO from the column at top left.

Then read across on that line to your f/stop.

Then read down for shutter speed.

Eclipse Exposure Table ISO F/Stop 100 2.8 4 5.6 8 11 16 200 4 5.6 8 11 16 22 400 5.6 8 11 16 22 32 800 8 11 16 22 32 45 1600 11 16 22 32 45 64 Phenomenon Shutter Speed Partial Phases ND5 1/8000 1/4000 1/2000 1/1000 1/500 1/250 Diamond Ring 1/500 1/250 1/125 1/60 1/30 1/15 Baily's Beads NA NA 1/8000 1/4000 1/2000 1/1000 Chromosphere NA 1/8000 1/4000 1/2000 1/1000 1/500 Prominences 1/8000 1/4000 1/2000 1/1000 1/500 1/250 Corona 0.1 Rs 1 1/2000 1/1000 1/500 1/250 1/125 1/60 Corona 0.2 Rs 1/500 1/250 1/125 1/60 1/30 1/15 Corona 0.5 Rs 1/125 1/60 1/30 1/15 1/8 1/4 Corona 1.0 Rs 1/30 1/15 1/8 1/4 1/2 1 Corona 2.0 Rs 1/15 1/8 1/4 1/2 1 2 Corona 4.0 Rs 1/4 1/2 1 2 4 8 Corona 8.0 Rs 1 2 4 8 16 32 Earthshine 1 2 4 8 16 32

1. Rs is the corona measured in solar radii. One solar radius is about 700,000 km, 420,000 miles, or 16 arc minutes. The extent of the corona is measured from the tip to tip of the corona across the entire field. So a corona that is 8 solar radii would be stretch about 4 degrees from side to side and would require a 300mm lens.

2. Exposures for the sky background are for two stops under middle gray, what would normally be considered the correct exposure if you exposed according to what your camera meter told you if it was sensitive enough to measure light levels this low. This will produce a dark blue color for the sky. As you can see from the chart, these exposures get ridiculously unusable at high focal ratios.

Important Note: These exposure times are suggested starting points only! Optimum exposures may vary widely based on the eclipse itself, your equipment, and viewing conditions. For example, if you are shooting with a catadioptric mirror lens, the actual transmittance of the lens may be slower than the listed focal ratio so you would need to increase these exposures. If you have thin clouds, haze, smoke, or if the eclipse is at a low elevation in the sky, you will need longer exposures. Your best bet is to use the old professional photographer's trick of bracketing. Bracketing means taking several different exposures over and under what you think the correct exposure should be. For example, if you thin the correct exposure is 1/500th second, then bracket and take exposures at 1/1000th, 1/500th, and 1/250th second.

For totality, with the Sun high in a clear sky, I suggest starting at the exposure for Baily's Beads at second contact. Then methodically increase your exposure by one stop increments until you reach your longest exposures at mid-totality. Then start decreasing your exposures, again by one stop increments, until you reach the exposure Baily's Beads at third contact at the end of totality. You can try increasing your exposure by several stops for the Diamond Ring after third contact.

If the focal ratio of the lens or scope that you plan to use is not exactly at a full f/stop as in the table above, use the Equivalent F/Stops and Intermediate Shutter Speeds in 1/3 stops tables below in the appendix to interpolate the correct shutter speed for your system.

Exposure Sequence

Our general philosophy is to shoot short exposures at second contact at the beginning of totality and at third contact at the end of totality. These short exposures will record any prominences and chromosphere which are visible only at the beginning and end of totality. The chromosphere is only visible for a second or two. Don't take any exposures longer than 1/30th of a second in the 10 seconds after second contact or in the 10 seconds before third contact.

If your setup allows it, shoot frames continuously at second and third contacts without pausing between frames becuase Baily's beads last for only a couple of seconds. If you do this, you may need a pause a little bit to let the memory buffer in the camera write to the memory card in the camera.

As we progress further into totality, and the Moon is more centered over the Sun, we will use longer exposures. We want to time it so that at mid-totality we are making our longest exposures. You want to time it so your short exposures are at second and third contact and your longest exposures are at mid totality.

Here is an exposure sequence for 1 minute and 57 seconds of totality for the eclipse at Madras, Oregon that I plan to shoot with a 65mm f/6.5 refractor with 420mm of focal length:

Duration of Totality 1m 56.4s (total solar eclipse)

Duration of Totality 1m 57.1s (lunar limb corrected)

Here are my final adjusted exposures after a lot of testing (note some are different than the originally published version, which was just my initial plan).

Time Contact Exposure #Frames ISO Notes 09:06:40.5 a.m. C1 -------------------------------- 1st Contact - Start of Eclipse C1 + 1s 1/2,500th 14 100 Partial Phases - intervalometer (Baader AstroSolar Film Filter) C2 - 30s --------------------------- TAKE FILTERS OFF C2 - 10s 1/200th 6 200 Diamond Ring C2 - 3s 1/8000th 3 100 Baily's Beads 10:20:32.4 a.m. C2 -------------------------------- 2nd Contact - Start of Totality C2 + 00s 1/4,000th 2 100 Chromosphere C2 + 03s 1/2,000th 2 100 Chromosphere C2 + 06s 1/1,000th 1 100 Prominences C2 + 09s 1/500th 1 100 Prominences C2 + 12s 1/250th 1 200 Inner Corona C2 + 15s 1/125th 1 200 Inner Corona C2 + 18s 1/60th 1 200 Inner Corona C2 + 21s 1/30th 1 200 Inner Corona C2 + 24s 1/15th 1 200 Inner Corona C2 + 27s 1/8th 1 200 Middle Corona C2 + 30s 1/4th 1 200 Middle Corona C2 + 33s 1/2th 1 200 Middle Corona C2 + 36s 1 sec 1 200 Outer Corona C2 + 40s 2 sec 1 200 Outer Corona C2 + 45s 4 sec 1 200 Outer Corona C2 + 50s 6 sec 1 200 Earthshine 10:21:30.5 a.m. ------------------------------------- MAX ECLIPSE C3 - 58s 6 sec 1 200 Earthshine C3 - 50s 4 sec 1 200 Outer Corona C3 - 45s 2 sec 1 200 Outer Corona C3 - 40s 1 sec 1 200 Outer Corona C3 - 36s 1/2th 1 200 Outer Corona C3 - 33s 1/4th 1 200 Middle Corona C3 - 30s 1/8th 1 200 Middle Corona C3 - 27s 1/15th 1 200 Middle Corona C3 - 24s 1/30th 1 200 Inner Corona C3 - 21s 1/60th 1 200 Inner Corona C3 - 18s 1/125th 1 200 Inner Corona C3 - 15s 1/250th 1 200 Inner Corona C3 - 12s 1/500th 1 200 Inner Corona C3 - 09s 1/1000th 1 100 Prominences C3 - 06s 1/2,000th 2 100 Chromosphere C3 - 03s 1/4,000th 2 100 Chromosphere 10:22:28.8 a.m. C3 -------------------------------- 3rd Contact - End of Totality C3 + 0s 1/4,000th 5 200 Baily's Beads C3 + 03s 1/200th 5 100 Diamond Ring C3 + 30s --------------------------- PUT FILTERS BACK ON C3 1/2,500th 14 100 Partial Phases - intervalometer 11:42:21.7 a.m. C4 -------------------------------- 4th Contact - End of Eclipse

Note - The table above was under construction and values and times have changed since it was originally published.

With BackyardEOS, if the camera settings such as exposure need to be changed, there is a minimum overhead of 3 seconds between frames for that information to be sent to the camera.

All exposures assume a clear transparent sky.

It is absolutely critical that you practice running this exposure sequence with whatever camera-control software that you plan to use. Time how long it takes. Spread things out so if you start the series when totality begins, it will end when totality ends.

Believe me, many things can go wrong here. Most DSLRs take about 3 seconds between frames when controlled by the manufacturer's SDK through software through a USB Cable. It takes that long for the information about shutter speed and ISO changes to be transmitted and set in the camera.

Using a program like Astro Photography Tool, or Eclipse Orchestrator, can speed up this process by using a serial cable to trigger exposures while the USB cable sends camera settings.

Calibration Images

For the seriously obsessive-compulsive, bias, dark and flat-field calibration images should be shot.

Because of the high ambient temperatures during the summer, any long exposures are probably going to have some thermal signal that should be subtracted from the light frames.

Flat-field images - Shoot your flat-field frames immediately after the eclipse is over. A flat-field frame is a picture of an evenly illuminated surface or scene, such as a clear blue sky, or the sky shot with a double-layered white T-shirt pulled taught over the end of your scope and held in place by a rubber band. It must be shot with the camera in exactly the same orientation in relation to the telescope, and at the same focus. If you are using a camera lens, the aperture must be set to exactly the same as it was during the eclipse. If you are using a telescope, the aperture won't change. Use the same ISO as your eclipse images. You can use Aperture Priority automatic exposure. Take a minimum of 4x the total frames you have shot of totality. More is better. If exposures are longer than 1/30th of a second, shoot dark frames for your flat exposures as well.

Bias images - Cover the lens with its lens cap, or take the camera body off and cover it with the body cap. Shoot the shortest exposure that the camera is capable of at the same ISO as your eclipse images. Take 4x the total number of eclipse images.

Dark-frame images - Cover the lens with its lens cap or take the camera body off and cover it with the body cap. Shoot exposures at the same exposure times and ISO as your eclipse images. Shoot 4 dark frames for every exposure longer than 1/30th of a second. If you shoot 2 four-second exposures on each side of your longest exposure, that means you have 4 total, and need 16 dark frames each four-seconds long.

As with calibrating for long-exposure deep-sky astrophotography, the more calibration frames you have the better. Once the eclipse is over, there's no reason not to devote some time to shooting these calibration frames, they are not going to take a lot of time. A total of 64 each would be a good number to aim for but may be a little unrealistic for each dark longer than 1/30th of a second if you go all the say down to 4 or 8 seconds. In that case, a minimum of 9 would be better. Remember you need darks for each shutter speed you use.

Automation

If you want to photograph the eclipse, the best way to do it is with automation. It does, admitedly, increase the complexity slightly, but it frees you to devote the majority of your attention to the eclipse itself. If you have ever used a camera control program for long-exposure deep-sky astrophotography, you will already be familiar with how some of these work. If not, you are going to have to learn them, but it will be worth it. And, even if you are experienced with them, you will need to practice using them well before the eclipse!

Camera Control Software

You have several choices for automation software to control your camera. With some you can specify when the camera will start taking pictures and it can take a series of images at different exposures and even different ISOs as necessary during totality to capture the range of exposures necessary for an HDR image.

Astro Photography Tool (APT) by Ivo Stoynov at Incanus Ltd. for Canon DSLR and QHY and other CCD cameras. APT is quite inexpensive at €18.70 Euros (about $21 USD) but very powerful. You can set up an exposure sequence with multiple frames at each exposure, pause between frames, lock up the mirror, and even pick a specific time for your sequence to start. It also has a method to speed up the camera's natural built-in pause between frames for changing settings by using both a normal USB cable and a serial shutter-release cable. I'm leaning towards APT right now because it has an automatic time-based start feature and can use both a USB and Serial cable to speed up image acquisition.

BackyardEOS (BYE) by Guylain Rochon at Otelescope for Canon DSLR Cameras. Cost is $35 for the classic edition and $50 for the premium edition. BYE will let you set up an automated exposure sequence with multiple frames per exposure. You will have to manually start the exposure sequence at the right time.

BackyardNIKON (BYN) by Guylain Rochon at Otelescope for Nikon DSLR cameras. Cost is $35 for the classic edition and $50 for the premium edition. BYN will let you set up an automated exposure sequence with multiple frames per exposure. You will have to manually start the exposure sequence at the right time. If I use the D5300 I will have to use BYN, which should be fine for controlling the camera. I will just have to start the sequence manually.

EclipseDroid (ED) by Wolfgang Strickling for Canon and Nikon DSLR cameras for Android smart phones. You will need a USB OTG ("On the Go") cable with a male micro USB connector on one end and a female full size USB port on the other. I could never get EclipseDroid to work with my Canon DSLR cameras. It would connect and I could take an exposure with the test function, but when running the eclipse script, timings were never correct and shutter speeds and file formats were never correct. I could never get my Nikon D5300 to connect at all even though the Android OS asked if I wanted to make EclipseDroid the default application when it connected. YMMV.

Eclipse Orchestrator (EO) by Fred Bruenjes at MoonGlow Technologies - for Canon DSLR cameras and Windows PCs. Very sophisticated and powerful, but complex. A free version gives you limited automation. The full $109 version gives full automation with faster shooting by combining a USB and serial-shutter release cable. Alternate emergency exposure sequences for scenarios like only having a brief amount of time to shoot between hole in the clouds. I'm not sure I can get to know it well enough and get enough practice to trust myself using it for the eclipse.

Solar Eclipse Maestro (SEM) by Xavier Jubier for Nikon and Canon DSLRs and SBIG and other CCD cameras for Max OSX. Very sophisticated exposure sequencing, similar to Eclipse Orchestrator but for Macs.

SET'n'C (Solar Eclipse Timer and Camera controller) by Robert Nufer for Canon DSLR cameras on Windows.

UMBRAPHILEX by Glenn Schneider for MacOS X - last release was 2009.

If you decide to use one of these programs, be sure to check to see if your camera is supported before buying it.

Automation Logistics

Here are the logistical problems with setting up your automation script.

If you're going to do the whole sequence and HDR bracketing, you are almost certainly going to need mirror lock up (MLU) for a certain range of exposures unless you have the world's most solid mount. And even then you will still probably need it for certain exposures where the resonant frequency of the entire rig matches the mirror slap frequency. With almost all of these programs, except Solar Eclipse Maestro (SEM), you can't turn MLU on and off on a per line basis. And even Xavier strongly hints you would be crazy to try to do this, even if it is possible. MLU takes a certain amount of time. With BYE it's 2-3 seconds minimum per frame. Other programs do it faster, but if you go too fast, you start skipping frames and sometimes the exposures go haywire. The Nikon D5300 has something like MLU, but it's called "exposure delay" and it lasts about 1 second. But Eclipse Orchestrator for the PC allegedly doesn't support the 5XXX level Nikons. Although I seem to have my D5300 working with it, I certainly need to do a lot more testing. SEM can vary the time of MLU with a Canon from about 1/2 sec to 1 sec to 2 sec to 3 sec, so you can go faster with SEM than with BYE. A big problem is that SEM only works on a Mac. If you are crazy but really know what you are doing, (there are even tutorials out there on the internet on how to do it), even if it's not legal, you can install a Mac OS X into a Windows virtual machine to run SEM on your PC laptop. This is really complicated and not for the faint of heart and I don't recommend it because you are multiplying the complexity by about 1,000x and something is likely to go wrong at just about 2nd contact. You need to use a fast SD card to achieve high write speeds. Some of these cameras can shoot 5 or 6 frames per second or more writing to the buffer and then to the memory card in the camera. But at some point the buffer fills up. I'm not exactly sure how the buffer works in relation to external control, but it would seem to me that if you don't try to change any of the exposure or ISO or f/stop settings and don't use MLU, you should be able to achieve a pretty fast framing rate until the buffer fills up. Try using the FOR loop in SEM and EO. In the end, you would want a fast framing rate for the Diamond Ring and for Baily's Beads, but not so fast you fill the buffer up and miss the chromosphere which is only around for about 6 to 10 seconds. After the chromosphere is hidden, you have a short period for prominences, but since this is solar minimum, you might not have any monster prominences like in 1991. Once you are into the HDR sequence you need for the corona, you can operate at a more leisurely pace using MLU. What you want to try to do is find the sweet spot between a maximum framing rate but not going too fast so you fill up the buffer in your camera when it's critical, such as right at 2nd and 3rd contact, or go so fast you start skipping frames in the sequence and getting your exposures all out of whack. You can only do this by a lot of trial and error experimenting. And it is time consuming. But, as noted solar photographer James Brown said, "You got to pay the cost if you want to be the boss." This is kind of advanced theory and I haven't tried it yet, but the thought just occurred to me that another solution might be in using SEM and EO "emergency" scripts. These allow you to run an abbreviated script if you have clouds and want to squeeze in some kind of shortened HDR bracket through a brief hole in the clouds. You could conceivably run your normal script and machine gun it at a high framing rate at 2nd contact with no MLU, run a more leisurely HDR "emergency" script with MLU programmed in for your longer exposure sequence bracketing, and then go back to the normal script with no MLU and machine gun it at 3rd contact.

Practice and Test Your Setup and Control Program! I can't say this enough. No matter what software you use to automate your image acquisition, you need to practice and test it over and over again.

Accurate Location and Time

Having your computer set to the accurate location and time is critical for automation. The critical eclipse contact times and when totality starts, and how long it lasts, is based on your location. It is different for every location along the path of totality. If you observe the eclipse in Oregon, totality is only going to last about 2 minutes. If you observe it near Carbondale, Illinois, it's going to last about 2 minutes and 40 seconds. For a given general location, totality lasts longest on the "centerline". As you move towards the edge of the path of totality, the length of totality gets shorter.

Near Madras, Oregon, totality starts at 17:19:37.6 UT, and near Makanda, Illinois, it starts at 18:20:30.7 UT.

So you have to know your location and the correct time. This is particularly with programs like Eclipse Orchestrator and Eclipse Maestro that calculate the exact circumstances for the eclipse based on this information and then automatically take exposures at exactly the right time.

Exact location is easy, you get it from the GPS on your phone. Google Maps will show it to you if you can get a WiFi or cell phone signal where you will be located. But it's possible you may be out of WiFi and cell tower range, and the cell towers may be overloaded with folks live streaming the eclipse. So don't count on them.

You can download a simple app for the Android smart phone like GPS Coordinates that uses the GPS in your phone and GPS satellites to determine your exact location. Then you can input it into your camera control program if it requires it. You should be able to find something similar for your iPhone.

Use Xavier Jubier's Eclipse Path Google Map overlay to get the local circumstances of the eclipse for your location. Just click on a location on the map once you have zoomed in to your observing site. Don't forget that the times listed are in UT (Universal Time) and need to be converted to your local time.

As far as the correct time, you can also get that from GPS satellites without needing WiFi or a cell signal. Get an app like GPS Time. It will also tell you the accuracy of the time on your phone.

For your computer, if you have internet access, you can use this utility from the National Institute of Standards and Technology (NIST) called nistime-32bit.exe. It will automatically correct the time on your computer. You will have to run it with administrator privileges.

You can also call 303-499-7111 by phone to reach WWV Colorado to hear timing signals with a brief delays in the 30-150 milisecond range.

Here is an accurate web based time server:

Automation Tips

Use a large fast memory card and reformat it in camera before you start taking pictures. Don't forget to copy any pictures off the card before you reformat it!

If you automate your imaging capture with software, you will be able to fire more frames in a quicker amount of time if you write the image files only to the camera. It takes much longer to transfer the files over USB to write them to the computer controlling the camera.

If you automate and use a camera lens instead of a telescope, make sure you have the f/stop (aperture) set correctly for whatever exposure you calculate for a particular phase of the eclipse.

Computer Settings

Go to PC Settings > System > Power And Sleep and set both screen and sleep to "never". Turn off power saving in the computer including sleep and hibernation modes. Even if you are going to run it off the built-in battery, set it so the computer never sleeps, or you run the risk of it going to sleep right in the middle of totality. Naturally, you need to test to see how long your battery will last, and make sure you only turn it on a little while before totality. Shoot partial phases with a simple intervalometer like the Canon TC-80N3.

Go to PC Settings > System > Power And Sleep > Additional Power Settings > Choose or Customize a Power Plan > Change Plan Settings > Change Advanced Power Settings:

Turn Hard Disk Off After: 0 minutes (same as never)

Sleep > Sleep After: Never

Allow Hybrid Sleep: Off

Hibernate after: Never

USB Settings > USB Selective Suspend Setting: Disabled

Turn off the screen saver. PC Settings > Personalization > Lock Screen > Screen Saver Settings: None

Turn off Windows Updates - oh, that's right, you can't. So go to PC Settings > Updates and Security > Change Active Hours: set the active hours to the hours of the eclipse so it won't try to restart on you in the middle of totality. This is for Windows 10. If you are not running Windows 10, you should be for security reasons.

Camera Settings

Turn off power saving in the camera. Your camera also has a power saving function where it will turn itself off to save the battery. Turn this off, and as with your computer, don't turn the camera on until a little while before totality, just turn it on and off when you are taking snapshots. It's a good idea to put in a fresh battery a little while before totality. Read your manual to find this setting in the camera's manual.

Wide Angle Camera

Single Frames During Totality

If you plan to use a wide-angle camera to shoot just totality, set the camera to autoexposure at f/4 at ISO 200 and use a remote release so you don't jostle the camera when you press the shutter button blurring the picture. If you don't have a remote release, you can use the self timer. Read your manual to learn how to set it.

Multiple-Exposure Composite

If you plan to use a wide-angle to do a multiple-exposure composite showing partial phases leading up to, and after totality, you don't want to be there clicking the shutter every 4 or 5 minutes. You can automate this with a laptop, or, more simply, with an intervalometer. Just set the intervalometer to take a picture every 5 minutes.

The time to start the partial phases sequence is based on 1 exposure every 4 minutes and is calculated backwards from maximum eclipse.

For this location, maximum eclipse is at 10:21:30.5 a.m., so the partial pictures should start at 09:01:30 a.m. and end at 11:49:30 a.m.

This is a total of 46 filtered frames of the partial phases including 2 frames before the eclipse starts and 2 after it ends, including one long exposure at maximum eclipse with no filter.

The exposure for the Sun with the solar filter will be the same for all of the partial phases so use manual exposure. Usually your exposure will be around 1/4000th second at f/4 at ISO 200 with an ND5 solar filter. You might increase the exposure a bit in the last frame before totality due to limb darkening on the Sun. At totality, take the filter off and change the exposure to autoexposure at f/4 at ISO 200. Use a tripod. Be careful not to move the camera. Don't forget to take the filter off for totality! After totality ends, put the filter back on and set the exposure back to your partial phase filtered exposure.

The Full Monty

When someone goes crazy, and they want to take every type of eclipse photo all at one eclipse, we call this the "Full Monty."

They have never heard of the KISS (Keep It Simple Stupid) principle.

1,200mm for close ups of prominences, chromosphere, Bailey's beads on APS-C format camera.

1,200mm - Sun-grazing comets, undiscovered trans-mercurial planets.

600 - 800 mm for video of corona.

420mm for diamond ring and decent sized corona stills.

420mm for time-lapse from stills of all phases.

180mm for maximum corona and Regulus nearby stills.

85mm for portraits of folks watching with eclipse reflected in glasses.

50mm for eclipse crescents and group portrait.

16mm for wide-field multiple-exposure composite.

16mm for planets during totality.

16mm for 360° all-sky panorama.

Fisheye - 2nd contact Sky cut in half by moon's shadow, east horizon bright, west dark.

Fisheye - 3rd contact Sky cut in half by moon's shadow, west horizon bright, east dark.

Flash Spectrum

Polarized Corona

Wide-angle video with IPhone, Android, or DSLR for people;s reactions during totality.

Drone for aerials of approaching shadow, then zooming down over riotous crowd celebrating totality.

Notes

Scout your observing site day before. Find a scenic spot where you can set up to shoot both a wide-angle shot as well as set up our main scope very close nearby. You can't be taking off the filters for the wide-angle and scope at the same time if the two are not right next to each other. Try to arrive at the site the night so you can polar align if you are shooting long exposures on an equatorial mount. Having a bathroom nearby would be extra credit that would put you into the bonus round.

Use the solar rate on your mount!

If automating, turn off camera and computer sleep function.

Schedule a bathroom break into time line before totality.

Shadow bands 1 minute to 30 seconds before and after totality. Try to shoot on video.

Determine the exposure for your f/stop and ISO in the Eclipse Exposure Table above.

Make an automated exposure sequence like the one in the list above once you know the correct exposure for various features of totality.

Have several backup plans for all contingencies, such as: Clouds - you might only have a period of time shorter than totality to shoot if you have clouds and can only shoot during a brief break in the clouds. Different location - you might have a shorter or longer period of totality if you decide on a different observing location the day before the eclipse due to forest fires or weather. The length of totality is critical to automating the timing of events at second and third contact.

Practice on the Sun with a safe solar filter.

Practice on the full Moon without a filter.

Practice. Practice. Practice.

Practice some more.

Shoot Raw file format.

If you normally shoot with a skylight or UV filter on your camera lens to protect it, take it off for the eclipse or you may get reflections.

For Druckmüller-type HDR processing, the camera must be oriented so the Sun is in the center of the frames and the long side of the image is parallel to the Sun's equator.

Make sure you have a fast memory card for your camera, and also one with a large enough amount of memory to hold all of the frames that you will shoot during totality. You do not want to be changing cards during totality.

Use an intervalometer like the Canon TC-80N3 for the partial phases to save the camera control laptop's battery. The exposure will stay the same throughout totality, so you only have to set it to take a picture every 3 to 5 minutes to get a nice sequence of the partial phases.

Don't forget to focus on the Moon's limb or on a Sunspot just before the start of totality. Do this through your safe solar filter. Since the filter is in front of the main objective, the focus should not change when it is removed for totality.

Change the camera battery before totality.

Don't touch the camera during totality. Don't even look at it, remember, you automated it, right? Instead, look at the totally eclipsed Sun and marvel at its majestic beauty!

If something goes wrong with your photographic setup, don't try to fix it. Just ignore it, and enjoy the unforgettable and wonderful sights of totality. I can absolutely guarantee that you will not fix a problem in 2 minutes. You can always look at someone else's photos later, but you can only experience totality for yourself in real time!

Be sure to remember to remove your safe white-light solar filter about 30 seconds to 1 minute before totality so you can be ready for the Diamond Ring. Be sure not to jostle the camera as it could affect where it is aimed. You should practice this also before the eclipse. And rehearse where you will put the filter so you can find it when totality is over. Put the filter back on just after the end of totality after the Diamond Ring at 3rd contact.

Back up your images immediately after the eclipse is over.

Top 10 Tips

Be sure you are inside of the path of totality. Outside of it you will only see a partial eclipse. Totality and the corona are the BIG deal. Unless you actually live in the path of totality, give yourself a lot of extra time for travel and plan to arrive early. Don't think you can drive up at the last minute and pop out of your car and watch the eclipse as the roads may be jammed. Bring a lot of water to drink. The eclipse takes place in the hottest part of the Summer and lasts for a couple of hours. And who knows how long you will be there with the traffic. Be sure you use a safe solar filter during the partial phases for both visual use and photography of the partial phases. Do NOT look at the Sun with your naked eyes, or especially with binoculars or a telescope, if you do not have a safe solar filter. If it is your first total solar eclipse, don't try to take pictures, just observe and experience. If you take pictures, put your camera on a tripod. If using a long focal length like 400mm or more, it must be a rock solid tripod. Use a wide-angle lens and auto exposure. Focus beforehand on infinity and tape it down. Turn off autofocus. Don't forget to take the filter off for totality! And replace it when totality ends. If you are planning elaborate photography, practice!

The following is a random extra tip presented to you as lagniappe

Finding the Sun with a filter on your camera or lens.

With a safe solar filter on your lens or scope, all you're going to see when the Sun is not in the frame is black. So how do you get the Sun in the frame, particularly if you are at a long focal length?

The easiest way is with a solar finder. It can be the normal finder on your scope with a solar filter on it. Or it can be something simple like a small device with a simple pinhole that projects an image of the Sun onto a flat surface on the device that is mounted on your scope like a finder, or in the hot shoe of your camera. You can even make one of these yourself.

If you don't have a solar finder, or forget it at home, here is an easy way to get the Sun in your camera. Simply look at the shadow cast on the ground by your camera and lens or scope. As you move the scope around aiming it, you will notice the shadow become the smallest when it is pointed right at the Sun. Voilà!

Here's another one: best hamburger in Portland Oregon: Stanichs. 4915 Northeast Fremont Street, Portland, OR 97213

Appendix

Equivalent F/Stops

Here is a table giving equivalent f/stops for intermediate f/stops. If your scope is not exactly the f/stop listed in the eclipse exposure table above on this page, you can calculate the exposure needed. For example, say you need a 1/2000th second exposure at f/5.6 at ISO 100 for prominences, but your scope is f/6.3. Find f/5.6 on the top line and drop down to f/6.3, and read the exposure compensation needed from the left-hand column. In this case it is plus + 1/3 stop. Use the tables below for the appropriate shutter speed. Here +1/3 from 1/2000th would be 1/1600th of a second.

F# 1.4 2 2.8 4 5.6 8 11 16 22 32 +1/4 1.5 2.2 3.0 4.4 6.0 8.7 12 16.6 24 33 +1/3 1.6 2.3 3.2 4.5 6.3 9.0 12.6 18 25 36 +1/2 1.7 2.4 3.4 4.8 6.7 9.5 13 19 27 38 +2/3 1.75 2.5 3.5 5.0 7.0 10 14 20 28 40 +3/4 1.8 2.6 3.6 5.2 7.3 10.4 14.5 21 29 42 +1 2 2.8 4 5.6 8 11 16 22 32 45



Intermediate Shutter Speeds in 1/3 stops Standard full stops based on a 1-second exposure as a starting point are in blue below. 1/4000 1/3200 1/2500 1/2000 1/1600 1/1250 1/1000 1/800 1/640 1/500 1/400 1/320 1/250 1/200 1/160 1/125 1/100 1/80 1/60 1/50 1/40 1/30 1/25 1/20 1/15 1/13 1/10 1/8 1/6 1/5 1/4 0.3 0.4 0.5 0.6 0.8 1 second 1.3 1.6 2 2.5 3.2 4 5 6 8 10 13 15 20 25 30 Bulb

Intermediate ISOs in 1/3 Stops Standard ISOs are in blue below. 100 125 160 200 250 320 400 500 640 800 1000 1250 1600 2000 2500 3200 4000 5000 6400 8000 10000 12800 16000 20000 25600 Standard ISOs are inbelow.

Use full ISO stops, such as ISO 100, 200, 400, 800 and 1,600.

There is rarely a reason to use anything higher than ISO 1600 with old non-"ISOless" cameras.

If you have a newer "ISOless" camera with low read noise at low ISOs, there is rarely a reason to use an ISO higher than ISO 400 as all you will do is sacrifice dynamic range at higher ISOs.

Calculators

Optical Density vs % Transmittance vs Exposure

ND % TRANS SHUTTER F/Stop ISO NOTES 5 0.001% 1/250 f/16 200 Baader Visual, Daystar Visual 4 0.01% 1/2,500 f/16 200 3.8 0.016% 1/4,000 f/16 200 Baader Photo density 3 0.1% 1/25,000 f/16 200 2 1% 1/250,000 f/16 200 1 10% 1/2,500,000 f/16 200 0 100% 1/25,000,000 f/16 200 Sun unfiltered

A transmittance of 0.001%, such as with an ND5 Baader Astro Solar filter, means that only 1/100,000th of the original light is transmitted through the neutral density filter.

ND 1.0 = 3 1/3 stops= 10x difference in exposure

ND 3.0 = 10 stops difference in exposure = 1024x = 2 10

ND 3.8 = 12 2/3 stop difference = 0.016% transmittance = 6,750x

ND 5.5 = 16 2/3 stop difference = 0.001% transmittance = 104,152x

By test I know that the correct exposure for the Sun with an Baader ND 3.8 Baader Photo Density filter is 1/4,000th second at f/11 at ISO 100 at noon in clear sky.

What is the exposure for a Baader ND 5 filter at f/11 at ISO 100?

Calculations:

ND 3.8 to ND 4.0 = 2/3 stop = 1/4000th to 1/2500th

ND 4.0 to ND 5.0 = 3 2/3 stop = 1/2500th to 1/250th

ND 3.8 to ND 5.0 = 4 1/3 stop = 1/4000th to 1/250th

The exposure for ND5 is 1/250th at f/11 at ISO 100.

Neutral Density filters on Wikipedia.

Image Scale per Pixel

Input the focal length of your lens or telescope.

Input your camera's pixel size.

Click the "Calculate" button. Focal length of scope in mm Pixel size in microns Arcseconds per pixel

Equipment Lists

Main Scope

AT65Q

Solar Filters

Mylar scope covering

AP 2x Barlow?

Mounting Rings

Dovetail Plate

Solar focusing cloth / Mylar blanket?

Guiding eyepiece for drift polar aligning

Main Mount

Losmandy GM-8 or AP Mach1

GM-8 Custom dec plate

GM-8 Custom azimuth plate

GM-8 Drive electronics

GM-8 RA and Dec cables

GM-8 power cord

Cigarette lighter 2.5mm plug? (rental car may not have plug)

Dec Vixen Bar

Feisol heads x2

Gitzo tripod

Dog run ground screw

Cable to secure tripod to ground

Counterweight shaft and bolts and nuts

12-volt alligator clip power cable

12-volt alligator clip power cable to Anderson Power Poles

Power pole to 2.1mm plug calbes

Solar finder for lens in case you have to run to clear skies and set up at the last minute

Computers

Toshiba Laptop 1

Toshiba Laptop 2 ?

Winbook

Laptop 120v chargers

Laptop 12v to 19v power adapter

Backup Software on USB thumbdrive

USB button thumbdrive for sneakernet file transfers

Several USB button thumbdrives for data backup

Backup OS and Programs on extra Internal SSD hard drive

Laptop tent

USB thumb drives

GPS location and time phone app

USB cables

Serial cables

USB to serial converters

Mouse

small USB hub

Tiny wireless keyboard

Stylus pen for Winbook x2

Car charger for TalentCell battery.

7DMII requires USB3 MICRO

2 Micro USB cables for 7DM2

4 Mini USB cables for 700D and D5300

4 Micro USB cables for Galaxy Phones

Software on USB stick

Windows 10 install

BackyardEOS

BackyardNIKON

APT

Eclipse Orchestrator

Canon software

Canon drivers

Small Tool Kit

Kathy's Masking tape

Duct tape

Pocket knife - can't carry on

Jeweler's screwdrivers

Allen wrenches

Crescent wrench

Multiman tool - can't carry on

Rubber pads

Rubber bands

Superglue

iOptron SkyTracker Kit

iOptron SkyTracker

Polar scope

Batteries

Cables

Counterweight shaft

Counterweight

Ball head

Various assorted bolts

Loop bolt on bottom of tripod

12v lithium ion battery

Charger

Tripod

Bogen clamp and ball head if no separate tripod

Camera Equipment

Nikon D5300

18-55mm lens

180mm f/2.8 ?

Nikon intervalometer

Nikon USB cables

Extra Nikon D5300 battery

Battery chargers

SD Memory cards

Canon 700D

Rokinon 16mm f/2

75-300mm lens

Fotodiox Nikon-Canon adapter

D700 camera batteries

Canon TC80-N3 intervalometer

Extra 3.5mm to 2.5mm cable

Spare TC80-N3 battery

Mini tripod

2-inch T mount adapter

Compass

Lens cloth

Mini tripod

Bogen Clamp?

Ball heads

iPhone / Galaxy tripod mount

Lens cleaner

3x Dioper reading glasses for focusing

Tent stakes for mini tripod

Suitcase

Clothes

Medicine

Phone charger

Phone charger USB cable Android

Phone charger USB cable iPhone

Mylar space blankets

Toiletries

SQM Meter ?

Old weather radio

Personal Carry On

Phone

Wallet

Keys

Extra Phone Case Battery

Boardi