Sirsalis

Move your mouse over the picture to see the names of the various features.

Sirsalis and Sirsalis A make a nice doublet in the far south-western area of the Moon.  One of the problems of imaging the Moon at this phase is the large dynamic range of lighting.  For this picture I intentionally overexposed the brightest parts in order to bring out the area closer to the true terminator, in particular the four craters Hansteen, Billy, Zupis, and Mersenius.  The latter is in fact in a very rugged area on the western shore of the Mare Nubium.  Also just visible is the Sirsalis Rille (Rima Sirsalis) which is one of the longest rilles on the Moon being over 300 Km long and extends well beyond the area of this picture.  It is a most unusual rille in that it cuts across highland terrain rather than skirting the edges of a mare like most rilles do. LPOD has a stunning image of it together with Dr Wood's usual authoratative description. The scale markers are approximately 100 Km north and east. The picture was taken in infra-red light with a ToUcam attached to my LX200 on 31st August 2005 at 04:31 UT when the Moon was 26.3 days old.

Date and Time	31st August 2005 04:31 UT
Camera	ToUcam 740K
Telescope	LX200 at prime focus (FL 2500 mm) with IR-pass filter
Capture	K3CCDTools. Low gamma, 1/25", 59% gain, 444 frames
Processing	Registax. 103 frames stacked. Wavelets 1-3 = 10, hiostogram 15-255, contrast 120

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