With the first quarter moon lighting up the sky, I used this evening to resurrect and tune up my old Celestron CG-11 setup on three planets - Venus, Mars, and Saturn, all shown at the same image scale. These images are not as sharp as you might find elsewhere on the internet. These days the preferred technique is to use a video camera and specialized software to sift through thousands of images which can be captured in seconds, but my digital camera (Nikon D70s) was more convenient. I manually snapped about a dozen shots of each planet to get these results, which I think pretty closely match the visual appearance through the eyepiece.
To capture these shots, these special procedures were used:
- Venus - High ISO and shutter speed (ISO 1600, 1/500 sec.) was used to beat the vibration of the camera's mirror and shutter. This single exposure shot was decomposed into separate RGB components and re-aligned in Photoshop to minimize the differential refraction effects of photographing through the thick atmosphere near the horizon.
- Mars - ISO setting: 200, ~1/2 sec. I set the camera for a 3-second exposure and uncovered/re-covered the telescope objective with a piece of cardboard to eliminate the vibration caused by the camera shutter and mirror. This is a single-exposure shot.
- Saturn - ISO setting: 200, ~ 1/2 sec. As in the case of the Mars shot, I set the camera for a 3-second exposure and manually exposed with a piece of cardboard. This is a two-exposure "stack".