If anyone would like to give me some suggestions on how to improve this image. Or, even have a shot at it. Then feel free!
This image was taken with a CPC1100, TV PM 2.5, and NexImage camera. I processed about 800 of 1000 frames using VirtualDub, PCFE, and Registax. I don't have Photoshop but do use Gimp. I couldn't figure out how to improve anything using Gimp, however.
Also, are those lines due to interlacing of the camera?
I hope you all are doing OK after all of the flooding and then a cyclone!
I'm starting to think the patterns you see (as in the dark frame you posted before) are caused by a repetitive/modulated type of noise (hum) - it's clearly not random noise that you can 'stack out'.
Depending on how still the image is between multiple frames (it shouldn't drift, but my educated guess from looking at the noise is that your polar alignment was very very good anyway), you may want to try to add an effect in Virtual Dub that averages a few frames together, such as a motion blur. Then maybe take the result and stack the resulting individual frames. This should hopefully blur the hum (but will keep Saturn still) so that the stacking algorithm won't detect too large peaks caused by the modulated noise.
The reason why this (might) work is that, if the noise isn't random, on average some pixels 'inherit' the noise more often than others, causing a pattern to emerge.
I'm thinking another way you could somewhat mitigate the problem is by not perfectly polar aligning your mount (introducing dither). This will cause Saturn to appear at different spots and will make Registax align the image accordingly. This means that the modulated noise moves (relative to Saturn) and will occur at a different spot every frame. This will help the stacker decide it's noise and not a real signal. Even better would be to move around Saturn around slightly in random directions every few frames (during capture - not in post processing!).
Thank you Ivo! I think your are right about the noise. And I intend on taking a closer look at my camera and cable. I will probably even go as far as opening up the camera, and maybe replace the cable with a better one. This really is a very thin USB cable. I noticed, during this imaging session, that I could see a direct relationship between the noise, and movement of the cable.
I am using the NextStar Alt/AZ mount from Celestron. So I won't be able to misalign the image any more than it already is. However, I am using PCFE, which crops and pre-aligns each frame before Registax gets to do its work. So maybe I should go back to processing the raw AVI and see if it helps with the noise.
I have attached another processed image. This time I used a raw darkframe which didn't give me the 'fabric' artifact. But, it appears to have reduced the horizontal lines quite bit!
