M101 - more data, wider field (Uwe Deutermann)

M101 - more data, wider field

One could almost say it is a yearly visit, M101 that is. It is an uncomfortable target, even with the high enough brightness and I was never super happy with the results so far. Hence I decided to give it a longer go again, this time with a lot of Hα since I had my NB filter wheel for several nights active for the early morning Milky Way targets. I must say, I do not regret that I did, since it made really a difference this time. Since I wanted to get a wider field as well (compared to last years image) I took a few RGB and a bit more Lum data, all at 300s this time, just wanted to see if this makes a difference as well.
And I think it did, although, I used last years data as well in this image, just for M101 and not for the surrounding area. So although it says 11 hours in the summary (this years addition), it is more like 30 hours for M101 itself.
And ... this is not the end of the story for this image since my plan for my next processing trial is using the very same data, but this time using the GHS script. I saw now several people having very good results with it, and I spruced myself a bit up with some reading and tutorials. I am already curious if this really makes a bigger difference. The result above is IMHO a good bar for it.
* This image was not submitted for IOTD consideration

B

Title: Overlay version, showing M101 in all its glory

Uploaded: ...

C

Title: Annotated image of the wide field

Uploaded: ...

D

Title: Annotated image of the cropped version

Uploaded: ...

E

Title: Love the wide images, had to do one for this area

Uploaded: ...

F

Title: GHS trials

Description: After some learning of the new GHS script and seeing a lot of fellow Astrobiners having some success with it I needed to try it out. If you wonder if I uploaded the correct image since it looks almost identical to my previous one: well, the results was actually almost identical. Not sure if I did everything correct, but I tried out different approaches with more or less the same results.

Short recap (opinion!) about GHS:
- The steps that many YouTube videos show make sense, I like that since it helps me remembering them.
- The color assignment in the first processing looks to me like an exaggerated arcsinh process. As this one the amount of stretch and corrections are very sensitive and need to be done carefully. Without using the color assignment the image is very low in saturation, hence almost unusable. The next time I will definitely stretch muss less in the first process.
- Stars are in general, and sorry for this harsh word, destroyed. They are very fuzzy and have some strange colors, especially the brighter ones (the Pepsi effect). I compared the HT with the GSH stretch just for stars and there will be no way that I will use GHS for them.
- In general the method is very sensitive, which is of course good since it gives enough room to "play" with, but it makes the processing definitely quite a bit longer since you can expect that you will not hit the sweet spot with the first trial.
- In my next project that I just started I used GHS for the individual channels, and THAT looked quite better (except the stars of course, which I will have to create in a different way after creating a starless image).

Summary: Interesting tool. Well thought through. Opens up many trials. Not for stars.

Uploaded: ...

Florida / Georgia Imagers
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ASI 6200 MM Pro

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Status	Advanced success
Started	...
Astrometry.net job	5957637
PixInsight job	NUOGS4YL0VB8I3NY32F5YRWPYET5TBUY
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	14h03m50s.520
RA (top/left)	14h08m28s.326
RA (top/right)	14h07m55s.885
RA (bottom/right)	13h59m02s.574
RA (bottom/left)	13h59m53s.630

Dec (center)	+54°19′39″.00
Dec (top/left)	+53°38′41″.50
Dec (top/right)	+55°05′19″.67
Dec (bottom/right)	+54°59′53″.88
Dec (bottom/left)	+53°33′29″.23

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