Wednesday, March 30, 2005

Raw Images of the Day

Since I've been gone a few days, here is a super sized "Raw Images of the Day":


Anonymous Phil Stooke said...

Regarding why Penelope crater on Tethys is so prominent: it lies on a gradational light to dark boundary on Tethys. The side of Penelope lying on the darker material is brighter, the side on the brighter material is darker. (dark material is west of Penelope). So the albedo variations in Penelope are opposite to those on the backround surface, making it stand out. Topo shading adds to this effect if the crater is illuminated from the east, but if it is illuminated from the west illuminaton cancels out the albedo pattern and the crater almost disappears. These comments are based on a very detailed study of Voyager images, presented at LPSC a few years ago. When the sun is overhead on Penelope the albedo pattern makes the crater look as if it is lit by a lower sun to the east.

3/30/2005 06:55:00 PM  
Blogger Jason said...

Thanks for the explaination. I knew about the light/dark boundary but didn't understand its relationship with Penelope. But when I need to identify a satellite, I can use Penelope as a "sign post" for Tethys (along with Odysseus and Ithaca Chasma) given its prominence in certain geometries.

3/30/2005 10:11:00 PM  

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