Tuesday, May 25, 2010
Chrysae, Tharsis and N. Lacus, May 22, 2010
22 May 2010, 19:32 UT
200mm SCT f/10
422x, seeing 4/10, trans 3/5
Accepted as an Astronomical Sketch of the Day.
Mars' apparent diameter is now reduced to around 6", which is far from a maximum of 14" I have viewed and sketched last January. Still, 5 minutes of observation time in not so ideal atmospheric conditions (lots of air turbulence) and bright moonlight were enough to detect the main albedo features on the surface of Mars, currently residing in the constellation of Leo.
I didn't think it worthwhile to use colour filters due to the limited seeing conditions. However a light blue filter could have slightly enhanced the visibility of the features.
The much reduced north polar cap was seen as tiny bright patch adjacent to Niliacus Lacus. Underneath, the prominent Mare erythraeum was also visible.
No other subtle features were detected along the edge of M. erythraeum next to Chryse. Tharsis appeared bright.
After the session, I was pleased to note that the Calsky simulation confirmed the small features I saw through the scope. Mars images taken by the renowed planetary astrophotographer Damian Peach taken an hour later are here. These images, showing detailed albedo features were published on May 27th.