astro pixel processor

[micheleorsini]

Hi!
does anyone ever tried stacking using the Astro Pixel Processor (APP) software? it is appealing to me because it runs on a Mac (DSS doesn't) and it should be able to mix different scale frames.

I've made an attempt but the image had something wrong ... Startools Wipe result was a disaster, most probably I used a wrong setting or I did a wrong operation with APP, the DSS stacked image, uinstead, become *awesome* after having post processed it with Startools (thank-you-again-Ivo!! will be on the gallery soon!)

Update: tried stacking by disabling every "apparently" disturbing APP feature (e.g. normalize background, align channels ...) still the result is poor and I cannot wipe the image:

wipe2.jpg (487.68 KiB) Viewed 14220 times

[admin]

Hi,

Sorry for the very late reply.

If it is still of help, I can tell from the screen shot that you have several dark anomalies in the data (e.g. dead pixels or other very low value pixels that are much darker than the real background).
Removing these, masking these out and/or bumping up the dark anomaly filter setting in Wipe should fix this.

For more information, see here;

http://www.startools.org/modules/wipe/usage/

[micheleorsini]

Thank you Ivo!!

unfortunately APP trial is no longer valid, and, btw, stacking on DSS did not create these problems in Startools. Thit make me think that dark anomalies are not at the core of the problem, maybe something else? APP is a bit "opaque" in its settings, there might be some of them that screws up the data

Anyways, I was looking for a stacking program for mac, and, to, be honest, I didn't like APP workflow! So, I going to give Siril a try and then let you know, I already used IRIS on windows and I've been able to handle the output with Startools without problems (IRIS usability is a nightmare unfortunately)

cheers

Michele

[micheleorsini]

Short news: I used the dark anomalies settings for another picture where wipe had problems in a a couple of picture points and ... worked like a charm!!

than you for the tip!

just a question: what about using the detect/remove of cold/hot pixels in DSS for this purpose? the problem is that I use a camera, so my temperature is high, and it is not easy to capture darks in the same range of parameters (read: temperature), having some help from the stacking software might make post processing easier (in case you are wondering: I already use dithering)

Michele

[admin]

Good to hear Michele!

I can't say for sure how (or how well) the detect/remove cold/hot pixel algorithms in DSS work.

Usually taking darks or dithering between frames takes care of the problem. If you haven't been dithering between frames, definitely start doing that as it has many other benefits for the fidelity of your data.

[Rowland]

Michele. Have you by any chance saved this image sets to cloud storage - dropbox or similar? If you have and don't mind sharing, I would like to try preprocessing with my Linux script. Otherwise, no need to go to the trouble of uploading. Just curious...

Rowland

[micheleorsini]

Hi Rowland!!
I have all my data on dropbox, do you need original lights + calibration files?

I can share everything (I'm not jelous ), including the final FITS so you can check your result with DSS stacked one

And, btw, anyone who wants to process the files is welcome

LIGHT: https://www.dropbox.com/sh/llnrqzwhhx1n ... 3Ejta?dl=0

DARKS: https://www.dropbox.com/sh/itnz06jzwufz ... VtPga?dl=0

FLATS: https://www.dropbox.com/sh/caqp65buzfqb ... kipya?dl=0

DARKFLATS: https://www.dropbox.com/sh/zxptf53uzc43 ... EaLha?dl=0

Michele

BIAS: https://www.dropbox.com/sh/1c6hpxm34rl5 ... Usrga?dl=0

[Rowland]

Thanks Michele. That's very generous. I will work with the CR2 files over the weekend. I am very interested in the comparison with DSS /APP.

[Rowland]

It was necessary to manipulate flat illumination to get a proper calibrated result. PixInsight does that well but not automatically. DSS and APP likely attempt the same, automagically.

With 50% binning I needed a Wipe dark anomoly of 2 - 3 to get a good result.

Proper flat illumination is difficult to achieve at times but very helpful. On top of that, dithering averages out errors inherent in DSLR image calibration - which is seldom perfect.

[micheleorsini]

thank you for the tips!!

I'm using a DIY flatbox but I'm considering buying one and the results are ... meh not perfect but maybe slightly better than a PC screen (I've noticed that PC screens might not have a uniform illumination)

I'm still learning and I should attempt to work with better frames (i.e. not mine ) first, because I still do not "perceive" image defects so accurately as you: several times people pointed at my frames saying "they have XXX defect" and I wasn't aware at all!

the point is that I prefer taking frames rather than post processing them! Startools is perfect for that because it leads to a good result without too many tweaks but I-must-learn how to postprocess to get the best from my efforts!

I don't remember whether I did dithering with those pictures or not; I started using it properly during the summer, so now I'm using it

Michele