Ursids meteor shower peaks on December 22/23, 2015

The major meteor event in December is the Geminids but there's another shower later in the month that's doesn't make as many headlines but on occasions can be quite good, the Ursids. With the radiant located close to the North Pole Star the Ursids are a Northern Hemisphere shower. They are much less dramatic than the Geminids with only about 10 meteors per hour visible but on several previous occasions they have shown significant bursts of activity and a re-occurrence may happen anytime.

This year's Ursid peak occurs on the night of December 22nd/23rd. The waxing gibbous Moon will obscure the evening viewing so the best time to look is during the early hours of the morning before sunrise. In addition the radiant point of the Ursid shower climbs upwards in the sky after the Moon sets.

Parent comet

The comet that sources and therefore responsible for the Ursid meteor shower is 8P/Tuttle (also known as Tuttle's Comet or Comet Tuttle). It has a period of 13.6 years and during the last perihelion on January 27, 2008 it was visible telescopically. Tuttle's comet passed Earth at a distance of 0.25282 AU (37,821,000 km or 23,501,000 miles) on January 1, 2008 and anticipation was high that the 2007 and 2008 showers may produce much increased activity but this was not to be. In the end only a small increase was noted.

Radiant

The radiant of the Ursids meteors is located in the far northern constellation of Ursa Minor, "The Little Dipper". With a declination of +76 degrees it's circumpolar from most northern sites and conversely fails to rise from most southern sites. It's positioned just a few degrees northwest of Kochab (β UMi - mag. +2.1).

Ursids Radiant and Star Chart - pdf format (credit:- freestarcharts)

What to expect

The best two nights to look for the Ursids are on December 21/22 and 22/23. Normally it produces a ZHR (Zenithal Hourly Rate) of about 10 although there have been at least two major outbursts in the past 70 years (1945 and 1986). During an outburst it can jump to at least 50 meteors per hour, propelling the shower into the realms of some of the better annual meteor showers of the year.

When observing meteors they can streak through the sky many degrees from the actual radiant so it's better not to look directly at it but at a large area of surrounding sky. To confirm an Ursid, trace back the meteor and it will go all the way back to the radiant.

Ursids 2015 Data Table