Hypnotic spiral artifact

[ICallHimGamblor]

I am a super-noob to both imaging and StarTools, but I have been noticing a recurring artifact in my processing attempts... a neat spiral (maybe circular) noise pattern around whatever I'm working with.

I have uploaded an example here:
http://www.astrobin.com/58101/

Here is the original stacked image:
http://www.astrobin.com/58100/

Admittedly, this is probably a difficult object: Hickson 93 with a Celestron 9.25, about 2 hours of exposure at ISO 400 from my backyard in Dallas. My suspicion is that I mostly just need more integration time, but the fact that this artifact keeps occurring makes me think I am doing something wrong.

I also admit that it's kinda cool in a hippy, acid-flashback kinda way, but that's not what I'm going for.

Any suggestions?


Thanks.

[admin]

Hi,

Looks like they're possibly remnants from Wipe. Increasing the precision parameter could possibly help, but what you need most are flat frames - the vignetting and gradients in the data are quite severe!

[ICallHimGamblor]

I actually had Flats, but I made them before I understood how to properly make them. I retook a bunch of them yesterday and restacked and everything came out much better. It is so much easier to process now, and now spiral silliness.

Thanks.

[admin]

Great to hear! The better the data, the exponentially easier it becomes to process and the sooner you can establish a workflow that works for almost all images you produce.