We knew those variations existed, but they didn't expect to see them so early in New Horizons' approach, according to project scientist Hal Weaver. He said at a press briefing today that they didn't expect to see the surface variations for another month. They were made visible thanks to a process of stacking multiple photos taken one after another, and deconvolving the result. Hal said that the astronomy community's deconvolution algorithms were developed after Hubble was launched with its initially blurry vision -- so the Hubble problem has had a silver lining for the New Horizons mission!

The most common question I've been asked about this image today is: Is Pluto lumpy? The answer is no; Pluto is round. It appears lumpy because of those very brightness variations that the scientists are so excited about. Wherever a bright spot is near the edge of the disk, it looks like an upward lump; wherever a dark spot is near the edge, it looks like a downward lump. The variations in surface brightness are probably going to make it very hard to figure out what kind of topography Pluto actually has until we're quite close to it. In the meantime, they make animations of Pluto very interesting!

The other big announcement today is that the New Horizons team has begun sharing their raw images on the Web! Unlike with the Jupiter flyby, where they shared lossless PNG-formatted data, they are putting the Pluto images out in lossy JPEG format, which reduces their quality. While of course I'd love to have PNGs, lossy JPEG format is a tradeoff I'm certainly willing to accept in exchange for rapid access to images that help me to follow the mission! They say that images will generally appear on the raw images website within 48 hours of their receipt.

I've spent some time on the raw images website this afternoon, and thought I'd give you a tour of the kinds of images you'll find there.

First of all, I can decode the filenames for you. The filename convention is:

lor_NNNNNNNNNN_MMMMM_sci_P.jpg

Where

" lor " tells you that it's a LORRI image

" tells you that it's a LORRI image NNNNNNNNNN is the mission elapsed time in seconds

is the mission elapsed time in seconds MMMMM is an "ApID", a hexadecimal code that contains information about the observation (see table below)

is an "ApID", a hexadecimal code that contains information about the observation (see table below) " sci " tells you that the data has been lightly processed from the raw engineering data (it is "Level 2" rather than "Level 1" data)

" tells you that the data has been lightly processed from the raw engineering data (it is "Level 2" rather than "Level 1" data) P is the version number (there may be multiple versions of images; it looks like the raw page links only to the latest-version one for each observation)

Here is a lookup table for the ApIDs: