Cassiopeia Observatory

D7000 DSLR Imaging of Moon Crater Gassendi

Posted: 26 October 2012

Opened the observatory Thursday, 25 October 2012, at 1829 MST, 72°F, to clear skies with no breezes blowing this night. This would be a short night of moon observing with the Meade 8" LX200-ACF and imaging with the Nikon D7000 DSLR. At 1834 MST, I started observing the very bright waxing gibbous moon at 26mm. I quickly switched to 206X for a terminator tour. Seeing was not good; it was so bad that focusing at 206X was difficult. Once I did a get a good focus, there were many nice sights along the terminator during a few brief moments of steady seeing. I tried viewing at 364X but the bad seeing made the viewing horrible.

At 1852 MST, I removed the star diagonal and added the focal reducer + visual back for D7000 prime focus imaging. I knew that I would need the focal reducer to capture the entire lunar disk as on the previous night the illuminated portion of the moon just fit in the camera FOV without the focal reducer. I then attached the camera. At 1856 MST, I captured this view of the moon, 1/400sec, ISO 200, cropped from the full-frame image:

I removed the focal reducer and began eyepiece projection (222X) imaging of the Crater Gassendi. I first took this "establishing shot" showing Mare Humorum, "Hat Trick", ISO 100:

Gassendi is the large crater in the upper left corner with Mare Humorum the large circular area below Gassendi.

I then took some HD videos of Gassendi at 1/250sec using ISO 3200 and ISO 6400. Unfortunately, both videos were too underexposed to be usable for stacking and seeing was so bad that no unblurred frames were available. Since I taken the single exposures using full-size RAW images, during post-processing I decided to just crop the above image to show the crater Gassendi:

Due to the bad seeing, the image is not great but it does show some details inside the crater.

I ended imaging at 1925 MST, switched back to the diagonal, and did some more lunar observing at 206X. Seeing was still not very good.

Closed the observatory at 1945 MST, 61°F.

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