3 replies to this topic

[dylanear]

I tried my first attempt at imaging using the ASIAIR and got reasonably decent initial results for M31 Andromeda even in very poor conditions, even with no flats, darks or calibration images of any kind, just multiple exposures and basic stacking. But upon actually looking all the resulting files on the ASIAIR today rather than just the jpgs exported to my phone during the night of observing, I was disappointed to find no stacked results other than JPGs, no high quality files other than the .FIT individual images. 

So I tried ASIDeepStack on my PC using the individual .FIT files and I got a very pleasing resulting image given the poor conditions during capture. So I save the results and get a JPG and a TIFF and the JPG opened in other software looks like the stacked results in ASIDeepStack, yet trying to open the TIF for fine tuning in Affinity Photo, or Capture One, or anything else I've tried I get a nearly black image with just a few stars barely bright enough to be seen. Trying to boost brightness a LOT and then getting black levels and contrast/gamma that resembles the JPG output has proven to be nothing but frustration. Affinity Photo gives a message saying it's assigning a sRGB color profile to the TIF on opening it because it has none defined in the file. Also none of the typical TIF file saving options are available like lossless LZW or ZIP compression so you get a rather huge uncompressed file?

Is this the same results others are getting from ASIDeepStack? Seems basically unusable for serious work, only useful for making basic 8bit JPGs with no options for the quality, file size even? Maybe this TIF color problem is a recent bug and not an issue that's plagued every version of the software?

And there's no saving the stacking/color settings from a session into a file or preset? 


This is the JPG output from ASIDeepStack. A reasonable looking JPG file.

 

 

 
This is the nearly all black TIF, which I don't think Cloudy Nights knows how to make a thumbnail of, or display in any way, maybe because it's lack of color profile and/or it's very minimal metadata? It looks NOTHING like the JPG and seems to have no color profile defined in it. And if I had to guess is just the linear float data ASIDeepStack computes in internally and has no transform to a screen/human vision compatible color space at all? This was opened and saved in Affinity Photo to add LZW compression as the original TIF was uncompressed, 48 bit (16bit per channel) and 64mb, over the size limit for Cloudy Nights Gallery. I hopefully changed nothing but adding the lossless compression, Affinity forced an sRGB color profile onto it on import, but I exported with no color profile or metadata and used the same 16bit per channel/48 bit bit depth. It looks the same when opened in Affinity Photo as the original. Apparently you can't view this in the gallery and there's no thumbnail, but if you right click and select "open image in another tab" it will download to your computer if you'd like to inspect it and hope that will work from this post too?
 

And the link to the gallery just in case:

https://www.cloudyni...eepstack-tests/

I'm trying my luck with DeepSkyTracker, but I'm having no luck getting a stack to have nearly the rather nice look the ASIAIR and ASIDeepStack gives me from the same .FIT files, but ONLY in the JPG file it saves, not the TIF??! The brightness, black level, gamma slider on the top right of DeepSky Tracker is HOPELESSLY imprecise, stays the same small, low precision size even if I full screen the interface on a 4K monitor. There's no numeric input or way to sue a larger, more precise slider so I can't get the fine control needed to get the right values from the FIT files out of the ASIAir. I know it's free software, but that's GLARING GUI design problem and a big limitation on what seems like great software, much more powerful than ASIDeepStack, that keeps it from giving as pleasing images as the simpler and very flawed ASI app?!!!
 

If anyone has a workflow for high quality, lossless, high bit depth stacks with wonderful, precise settings for controlling brightness, black levels, gamma and tones and colors in general, even if it's not especially cheap, I'm very interested! I guess I'm off to research the better options for stacking software now.... Maybe Siril???

[Cryhavoc38]

Use siril to stack your files which is part 1.

Then using siril, you need to process your stacked fits result file to bring out the image.

[bobzeq25]

You're on the wrong forum, this is for traditional imaging. What you want is electronically assisted astronomy.

You'll get MUCH better answers to your question there.

https://www.cloudyni...ost-processing/

[Ranger Tim]

The only file that has been stretched and saved is the JPG. The other 2 need to be stretched by additional software to be seen. This post-processing routine is part of the editing we perform for all of our stacked images in these formats. PM me for more information if you want. I have posted your (almost blank) image below after a basic autostretch in Pixinsight. I would have worked more on it but there are no calibration files and there are color problems.

 

There appears to be nothing wrong with the ZWO software. I had never used it but found it fast, easy and convenient. Thanks for bringing it to my attention. It should be great to use for EAA and for fast stacks and evaluating them. Files in .FIT or .TIF formats are typically not saved by stacking software in order for the user to manipulate them while Linear. Some processes work best when images have not been stretched yet, like Blur Exterminator, background extraction, etc. I recommend you move to at least a free software like SIRIL to do your initial post stack processing, then move to a conventional photo editor like Affinity. BTW, there were some weird color gradients in the stacked file which implies some debayer problems or the like. I don't know enough about that stuff to help. You could try Deep Sky Stacker unless you are a Mac or Linux user like me. I have run Deep Sky Stacker and it is good freeware but dated. It will allow you to save files as stretched JPG's I think.