Disappointing results with APP vs DSS stacking, when processing in StarTools

[BrendanC]

Hi all,

I'm trialling APP for the second time, as a stacker before processing in StarTools. First time around I didn't know what I was doing, this time a year later I think I'm more clued up - but I'm still not quite getting the results I'd expect when compared to the free Deep Sky Stacker, and I'm wondering whether I'm doing something wrong here.

I've been testing them against each other, trying to process them as closely as possible in StarTools, and honestly I'm not seeing much of a difference. My hardware is a modded EOS1000D, Sky-Watcher 130PDS on an NEQ6. I'm capturing using APT, then stacking in DSS using the Auto Adaptive mode, and in APP using the recommendations at https://www.startools.org/links--tutorials/starting-with-a-good-dataset/recommended-app-settings, then taking the linear output and post-processing in StarTools, without adding denoise just so I can really see what's going on. I use 25 flats, 25 dark flats and 50 flats each time.

Here are some examples:

 

Now, I'm probably still going to invest in APP because I've just started doing some Ha work and it beats DSS hands-down for that. But, I would kind of like APP to do much better at RGB work than DSS too, especially given the price, and given the amount of time it takes to process.

Is there anything I might be doing that is really badly wrong here, or some button or switch or tick box I should be looking at? Or is this really just a reflection of the limitation of my gear/technique?

Thanks, Brendan

[vlaiv]

2 hours ago, BrendanC said:

I'm still not quite getting the results I'd expect when compared to the free Deep Sky Stacker, and I'm wondering whether I'm doing something wrong here.

Well what are you expecting compared to DSS?

DSS is very good stacker - and there are only a few things that I object to it - otherwise it works just fine.

Given one set of data - there is only so much choice of stacking algorithm can do - in most cases, result of stacking will be more alike than different between different stacking algorithms - if all used properly.

2 hours ago, BrendanC said:

But, I would kind of like APP to do much better at RGB work than DSS too, especially given the price, and given the amount of time it takes to process.

Don't blame stacking software for color management - that is sort of your responsibility and if you don't properly color manage - you'll get "color nonsense" in any scenario.

[BrendanC]

My last point was really referring to how I'd expect APP to have yielded better results generally, rather than just giving me better results with Ha. I wasn't really referring to colour management.

I was just surprised that APP, despite taking much, much, much longer to produce a result, and being a pay-for product, didn't produce results that were much different from DSS in any respect that I could see. I know the maths is essentially the same. It just surprised me, is all, and I was looking for any recommendations that might help me get a better result.

[vlaiv]

I think that best you can hope are nuances.

Measure FWHM of a star in final stack and you might notice that APP produces somewhat tighter stars. Difference might be small enough not to be seen by eye, only measured.

Similarly if you select what appears to be uniform patch of signal and measure standard deviation on it (thus estimating noise) - you might find that APP one is slightly lower in noise than DSS - again - this is most likely in domain of measurement and probably not something that you'll notice readily in images.

Is that worth the money paid? Well - that depends, but I think that APP has some features that DSS does not have (like automatic mosaic stitching) - and that is probably where your money is spend.

[BrendanC]

I guess,  plus APP is being actively developed whereas DSS is quite static now. Still, Affinity Photo does a great job with mosaics, so I've decided to see if I can get better Ha results with DSS and if so, I'll probably stick with that and save myself £60!