I have been waiting all summer for a decent clear, dark night where I could try to capture a planetary image with the new camera. At last a chance arrived. The equatorial mount is quick to align, and once Jupiter was (just about) high enough I decided to take some data, in the hope of getting something that I could practice the processing steps with.
The problem with the planets is that they are small, tiny in fact, as seen in the sky. We observe them through the atmosphere that doesn’t often blur their images by less than 1 arcsecond, and Jupiter is only about 40 arcseconds across at present. This “seeing” also changes rapidly, so by eye the image rarely looks good. Here’s a 3 second clip showing the atmospheric turbulence when I was taking these images.
You can see the two main belts (dark horiontal bands) in the mid latitude regions of the planet even here, but the turbulence in the atmosphere is obvious. I am hoping that later in the autumn when Jupiter is higher in the sky around midnight, that I will get better conditions.
I have attempted to take images of Jupiter before, but the best I achieved was with my old 3 inch aperture refractor, which has a long focal length (nearly a metre) so produces larger images than my present (500mm focal length) telescope. However the pixels in the Nikon camera are also larger than in my new planetary camera!
This was in 2021 when Jupiter was fairly low in the sky even at its highest; the effects of refraction in the atmosphere (red at the top of this image, blue at the bottom) are clear. It shows almost nothing in the form of features; maybe a hint of a belt in the lower hemisphere. This is 1/50 second exposure.
I can now do quite a bit better. This is an image made from a stack of the best 5% of frames from a 120 second video taken at about 50 frames per second. The two main belts are reasonably clear, and darker zones towards the poles especially at the top (which is north here; my recent images are the “right way up”!).
With further processing the image can be sharpened, so much so that the red spot (lower right) becomes fairly clear, just to the south of the lower belt. I still consider this process to be a bit like alchemy; it’s a somewhat artificial sharpening process, but there’s no doubt that it can make features that are actually present in the data easier to see! This image is 200 pixels square, so shows that the camera resolution is quite well matched to the best sky resolution I can expect.
So, overall I am pleased with these first results, and hope for some good clear skies over the autumn so that I can do better. Next year Saturn will be somewhat higher in the sky as well, so worth making an attempt at that as well. I did not try Saturn this time, as it was really rather low in the sky when it was properly dark and clear.