I was unhappy with my featureless Saturn, so I decided to try again. This time, I started with some more fine tuning collimation. It never seems to be right in the dead center. But I believe it improved quite a bit. Also I followed closely some collimation techniques. Chose a more suitable star on the Zenith, not to bright, not to dim. Zoomed in as much as I could and work my way in.
Another difference this time, was that I decided to take way more frames. From a thousand last time, I changed to 6 thousand. Why is that? Planetary imaging suffers a lot with atmospheric disturbances, since we are trying to see such tiny details. So we use the technic called “lucky imaging”. Where we take a gazillion of pictures, but only actually uses a small fraction of it. Only the lucky pictures where the atmospheric disturbances are minimal or nonexistent. It is, of course detected automatically. Trying to select the couple of hundred pictures on a several thousand set of pictures would take forever.
Another difference in the acquisition was ISO/Gain and Shutter speed. I have read in a planetary imaging tutorial that longer exposures and lower ISOs are better to spot better details. So I’ve tried that as well.
Saturn with its rings
Celestron AVX 8″ SCT
Focal Length: 2032 mm
Exposure: 6000 frames
Post processing: RegiStax 6
Taken May 14, 2015 around 00:32 CEST
Although it still not a very good sharp focused picture, it looks way better than the previous one. It is possible to see some features on the rings, and the color difference. Almost possible to see the gap on the rings what should appear there.
It still far away from a good picture, but with practice and experimentation, I believe I can improve it even more.