Wipe can be hard to learn, especially for a beginner, since beginner data tends to push Wipe to the edge. Mine sure did! M31's can also be weird, and the key to a lot of them is to use a mask to make sure that Wipe doesn't start erasing chunks of the galaxy, mistaking them for gradient. In my limited experience, I think I've seen more M31's need a Wipe mask (in reality an "unmask") than anything else. Check the ST main website for Wipe usage info, as well as the user notes sections here for additional reading.patraip1 wrote: ↑Tue Oct 19, 2021 4:35 am Hi Mike
Thanks a lot for your effort!!!
That looks way better than mine lol!!
At this point I am just experinenting with ST....
I woukd appreciate some help with wipe
I think the tablet I am using for taking flats may be small so I am not illuminating evenlemy the entire entrance of the scope. Will try again
Thanks for the help
Practice making your unmask for M31 (the lasso works well) and adjusting parameters. You'll see it if you've gone overboard. On your M31, my parameters ended up being DAF 4, CF 0.7, and Gradient 94%. This is 1.8 beta, so skip the CF if using 1.7.
Still, your processing will improve much if you get the acquisition, calibration, and stacking all sorted out.
I tried to make something out of your M33, and failed. Maybe Ivo's skills are needed here. But really, IMHO you are fighting the calibration problems mostly, so even though you kinda-sorta got a fair image out of it (your first one anyway), there's still all sorts of remnant vignetting that's left over and pretending to be part of the outer galaxy.
I looked at your subs, and even gave them a run in DSS as a mini-stack. Better, but at only 2 minutes integration I couldn't pull anything out of it.
I only used the lights, flats, and bias. Generally no need to use both bias and dark flats. And at such a short exposure time for the DF's, they are nearly identical to the bias anyway. Since you don't have darks, and DSS doesn't allow you to create your own calibration formula, just use the bias here. In that way, your lights will be bias-subtracted, as will your flats, resulting in proper calibration for the division.
Thus, when I used DSS with only your lights, flats, and bias loaded, I think it worked out better. Hard to tell without the whole enchilada, of course. I used ST recommendations, as well. Still a big gradient to deal with and I cropped a bunch off, but Wipe handles that far easier than what was there in your stack.
Your flats were well underexposed per the general rule, which is to be generally around 50% of your linear ADU histogram, not the stretched jpg BOC histogram. You may want to try longer flats. On my D5300, I expose them to about 7/8 BOC histogram, also ensuring that all three channels are captured and not clipped.
Finally, to be on the safe side and because Iris showed a really bizzare histogram shape for your flat NEF's, I ran all your files through Adobe DNG converter and then Mark Shelley's Nikon file fixer (ring remover), which smooths out data errors resulting from lossy NEF compression. You may want to look into that eventually, although the D5500 I think has a less harsh compression.
You might consider a light pad (tracing thingy) for flats. I just started using one after taking them with my laptop screen for a year, and I think they are coming out much better.
Let us know what you come up with after making a few fixes!
It's possible that green bias was reduced too much in color, so a little boost to that might clean it up, as well as make the stuff that should be blue...blue again.
