Messier 27 Data

[Burly]

Recently upgraded to a zwo533mc camera and using a skywatcher 200PDS, i managed two nights of imaging M27 in Bortle 5 sky , first night no filter other than a IR filter and second night using a L Enhance filter Stacked in Astap then Aligned both files in Astap so feel free to have a play with the Data in Startools ,Darks ,Flats and Bias frames used each sub is 180 seconds number of subs in file header ,the Rgb data i used Gain 100 offset10 the L Enhance i used 120 Gain and 10 Offset ,i would be intrested to see how ivo finds the Data .


Note updated and restacked files
https://www.dropbox.com/sh/j8jzi6smizsm ... 26h4a?dl=0

Regards Dave

[LuckyEddie]

There's something odd going on with the 2021-08-13 stack. There's a repeating single pixel artefact across the whole image at approx 26 pixel spacing...

[Burly]

There's something odd going on with the 2021-08-13 stack. There's a repeating single pixel artefact across the whole image at approx 26 pixel spacing...

Thanks Eddie i hadnt spotted that im now re stacking in astap to see what causing that .
Update 1/ restacked ,the problem seems to be when aligning and calibrating so will need to dig into this as the other file seems not to have the artefacts which may be a demosaicing artefact ,i have asked Han creator of ASTAP for guidance as i can see no setting that may be causing this ,Nb I think it may have someting to do with using a osc and a L Enhance duo band filter ,will update once Han gets back to me .

[LuckyEddie]

Here's what I got from the 2021-07-18 stack...

[admin]

Hi,

The stacks appear to be already color balanced, and it appears the color channels were not aligned properly, causing color fringing around stars for example.

That, and the little dots that are spaced every few pixels or so.

Hope this helps!

[Burly]

Thanks Ivo , I stacked both in ASTAP as per recommendation settings , the dots seem to be caused by Astap for some reason just waiting for Han to get back , the duo band data I tried in DSS and that had no dots that I could see though wasn’t to sure on the red channel around stars , I need to have a clear out and restack , check settings etc , I did upgrade ASTAP recently so will check the previous version and see if that creates the dots .
Note I just read on recommendation settings for Astap Do not align finished stacks against each other so this may be one cause as I aligned and calibrated the stacked fits .

[Burly]

@LuckyEddie i seem to have solved the issue which was caused by the flats ,updated ASTAP and ticked normalise flats osc Ivo checked the stack and all seems to be fine now, i have updated files in the link on first post .

Regards Dave

[LuckyEddie]

Here's what I got from the new data. I used Siril to register and stack the two files together first. Ivo's comment about the color channel alignment still holds. I used the lens module to slightly compensate by shifting the blue and red channels separately but that's not going to fully compensate.

[Burly]

Excellent result eddie maybe next time i will stick to same unity and offset