Dave Stearn avatar

M31 Critique please

This is a test image with only 5 hrs of data.

I will be adding more this week as well as Ha.

This was imaged with my wide field setup SQA55 2600MC Pro.

I tried to be more careful with the stars considering that the image is undersampled.

This was processed in Pixinsight using FBPP since this is a test.

https://app.astrobin.com/i/eykt0u

andrea tasselli avatar
Nice!
Tony Gondola avatar

I like that you’ve retained the star-like core.

Grigory2020 avatar

Oh man… I would die for an image like that.

sebaromano avatar

Colors look quite nice and natural. I won’t even touch it much more. We all have the tempation to boost colors and detials during last seteps of post-processing and ending up often with distroying the natural look.

Quinn Groessl avatar

Looks great. You could try adding some time towards Ha, but I don’t think it’ll really improve it much.

TiffsAndAstro avatar
Maybe some more Ha but I'd be extremely happy with this result as it stands smile
Vandewattyne avatar

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngimage.png

Dave Stearn avatar

Vandewattyne · Oct 26, 2025 at 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngimage.png

Dave Stearn avatar

Vandewattyne · Oct 26, 2025 at 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngimage.pngThanks, this could be due to my settings using Blur Exterminator. I will reduce the amount of sharpening

andrea tasselli avatar
Dave Stearn:
Vandewattyne · Oct 26, 2025 at 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngThanks, this could be due to my settings using Blur Exterminator. I will reduce the amount of sharpening

I doubt BXT can produce such a thing, it might enhance it but that is about it. The "hole" is due to pre-processing (CosmeticCorrection) with under-sampled stars, I suspect. This occurs when set to "Auto".
Dave Stearn avatar

andrea tasselli · Oct 26, 2025 at 08:06 PM

Dave Stearn:

Vandewattyne · Oct 26, 2025 at 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngThanks, this could be due to my settings using Blur Exterminator. I will reduce the amount of sharpening


I doubt BXT can produce such a thing, it might enhance it but that is about it. The "hole" is due to pre-processing (CosmeticCorrection) with under-sampled stars, I suspect. This occurs when set to "Auto".

CC was not set to auto

andrea tasselli avatar
Then some other settings, worth checking.
Rick Krejci avatar

Looks nice! I’d look into the star shapes, though. Besides above, they are cross/tic-tac-toe shaped. Did you drizzle? That may help

Dave Stearn avatar

I think I solved the star issue. With the 2X drizzled image I used Correct only BXT and then Resample down to the native resolution using integer Resample.

Dave Stearn avatar

Rick Krejci · Oct 27, 2025 at 01:00 AM

Looks nice! I’d look into the star shapes, though. Besides above, they are cross/tic-tac-toe shaped. Did you drizzle? That may help

At a high zoom you will see square patterns especially for small stars. The image was undersampled to begin with. I was able to 2X drizzle Gaussian and then Resample down after using BXT. From a normal viewing distance the stars should look good.

Aloke Palsikar avatar

Good colors and quality of image. Has come out well. I personally also have a SQA55 and hence can appreciate the wide angle view !

Great Effort !

Supportive
Al Loan avatar

Nice image, well done!

Manfred Baumann avatar

I like the “natural” colors. Looking forward to see the final result, maybe with Ha. From my POV, making the Ha regions more visible would add value to the image. I am currently working on a M31 image too, but I have to wait for better weather to finish.

Respectful Supportive
Rainer Ehlert avatar

Vandewattyne · Oct 26, 2025, 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngimage.png

Have you checked your alignment parameters?

Dave Stearn avatar

Rainer Ehlert · Nov 20, 2025 at 12:03 AM

Vandewattyne · Oct 26, 2025, 09:43 AM

Looks nice (colour & structure) but there are some weird stars, they look like an O.

📷 image.pngimage.png

Have you checked your alignment parameters?

How are you viewing the image?

Rainer Ehlert avatar

How am I viewing the image?

Well, on my PC monitor

Which software do you use for aligning?

Dave Stearn avatar

Rainer Ehlert · Nov 20, 2025 at 04:56 PM

How am I viewing the image?

Well, on my PC monitor

Reason I asked if you were to view in Classic Mode at full resolution the stars would look good. If you just zoomed in the image would appear stretched.

Rainer Ehlert avatar

Ah OK. I just answered to a posting where somebody posted a zoomed image. You wanted critique and some body found it out and it was not me, Sorry.

OK, I understand. I had a similar problem and then tweaked my Star Alignment settings and now everything is OK.

Rainer Ehlert avatar

OK, I tried to download your image in order to analyse it but it is not possible.

You know what, forget everything I wrote…

I made a single screen shot of one of the corners but did not find anything, so I really do not know where it comes from.

Sorry for having written those dumb comments…