Andromeda edit

[Iem1]

Evening folks,

Just looking for some opinions on some work I have been doing with Andromeda data. (Its about 1 hr 45 of 60 second subs, unguided)

I have had a few attempts at processing, and to be honest I am amazed at the difference between results!

Here was the initial attempt at a basic 'process':

 

And here is my latest attempt:

 

 

Quite pleased with the amount of detail I have been able to pull out of the galaxy, but I think the stars have taken a little bit of a beating! 

Does it look ok in general though? no glaringly obvious mistakes? I used PS, and at the end used starnett to focus a last stretch/sat of the galaxy.

 

Going to try get better data on the next clear night, really work on focus...may even drop exposure down from 60 seconds to 30 seconds as I think there is star trail creeping in, hopefully sharpen everything up. It was my 3rd or 4th attempt at a DSO afterall  

 

Original stacked tif:

Andromeda Stack tif.tif

 

[ONIKKINEN]

Thats a real nice result for a 4th try. I also processed the stack, just for practice as im still quite new and certainly not an expert in processing. I don't do any kind of star reduction so im not sure i improved on yours. What i will say is that the image has an overpowering blue tint to it, so colour balance seems a bit off. I used SIRIL (free) to do the initial processing, including background extraction, color calibration, and histogram transformation. Exported to photoshop for some final saturation and denoise touches. Also resized the image to hide problems in both my processing and maybe the data itself. I try to go for a very natural look with my shots, which is why i like the stars to remain bright, as they are several times brighter than the galaxy is supposed to be.

I noticed that you have some walking noise that is also in the direction of your star trailing, its difficult to notice but its there and its not simple to remove in processing. You can get rid of this by dithering! Especially important if using a DSLR since there will be a lot of all kinds of noise. You can dither even without any guiding setups, just manually move the camera a few pixels every now and then. The more you bother doing this the better it works but every bit helps.

Edited August 10, 2021 by ONIKKINEN
typo

[Gonariu]

I state that I do not know astrophotography, I like your photographs of M31 very much! Apparently where you live the white nights are over!

Edited August 10, 2021 by Gonariu

[Iem1]

5 hours ago, ONIKKINEN said:

Thats a real nice result for a 4th try. I also processed the stack, just for practice as im still quite new and certainly not an expert in processing. I don't do any kind of star reduction so im not sure i improved on yours. What i will say is that the image has an overpowering blue tint to it, so colour balance seems a bit off. I used SIRIL (free) to do the initial processing, including background extraction, color calibration, and histogram transformation. Exported to photoshop for some final saturation and denoise touches. Also resized the image to hide problems in both my processing and maybe the data itself. I try to go for a very natural look with my shots, which is why i like the stars to remain bright, as they are several times brighter than the galaxy is supposed to be.

I noticed that you have some walking noise that is also in the direction of your star trailing, its difficult to notice but its there and its not simple to remove in processing. You can get rid of this by dithering! Especially important if using a DSLR since there will be a lot of all kinds of noise. You can dither even without any guiding setups, just manually move the camera a few pixels every now and then. The more you bother doing this the better it works but every bit helps.

Thank you for taking a look mate

ahh I see the blue now having seen yours! I think it's because my dslr is astro modded, so I was fighting back an overwhelming red initially ..I will revisit the colour balance.

I took this picture before I made taking flats routine too, looking forward to another shot at it with full calibration frames. But I will certainly look into dithering, thank you for the suggestion.

I am really hoping the star trail is a result of my alignment being a bit out, rather than it being the result of asking too much from the rig (430mm focal sat on an unguided sky guider pro lol) 

I THINK my sadr region image is pretty star trail free by comparison  (thats over 2 hours at 60 second subs) or do you think it shows the same issues? If so, I might drop to 30 seconds and do some tests.

seen some brilliant M31 results online with even shorter exposure times than that!

 

[Iem1]

1 hour ago, Gonariu said:

I state that I do not know astrophotography, I like your photographs of M31 very much! Apparently where you live the white nights are over!

Thank you Gonariu!

I'm lucky to be able to reach decent dark sky sites, that image was taken in the Brecon Beacons (Wales, UK) which is a bortle 3-4 apparently. Just aswell, as I do not have any light pollution filters ..Although I think the moon was at about 70% and quite bright during that imaging session. I have yet to experience AP without the moon (Sadr region I got about half the imaging done before the moon rose though) 

hoping I can get out this evening and try again without any moon light, be nice to see the difference.

[alacant]

11 hours ago, Iem1 said:

Does it look ok

Hi

Yeah, it looks great. A big improvement. The data is good. 

A few bits and pieces, but I'm guessing as we don't know what camera or frames you took.

• There is horizontal banding (dslr?). Dither between frames.
• There is vignetting. Use flat frames.
• You lost a bit of the galaxy. Maybe ease off on the processing?
• To my eye, the background looks blue.
• Gather more and more frames.

Anyway, to get an idea of what's actually there, this is a 5 minute thrash in StarTools.

Cheers and HTH.

 

Edited August 10, 2021 by alacant

[Iem1]

1 hour ago, alacant said:

Hi

Yeah, it looks great. A big improvement. The data is good. 

A few bits and pieces, but I'm guessing as we don't know what camera or frames you took.

• There is horizontal banding (dslr?). Dither between frames.
• There is vignetting. Use flat frames.
• You lost a bit of the galaxy. Maybe ease off on the processing?
• To my eye, the background looks blue.
• G
• ather more and more frames.

Anyway, to get an idea of what's actually there, this is a 5 minute thrash in StarTools.

Cheers and HTH.

 

Thank you alacant!

The image was taken with WO Z73, astro modified canon 600D (or T3i I think it's called) sat on a sky guider pro, unguided.

It is about 1 hr 45 of 60 second subs, though I don't think the image quality reflects the integration time due to trailing/lack of calibration frames/possible dew on lens.

I believe I took dark frames, may have used bias frames and definitely did not use flats. I am in the habit now of taking full calibration frames

I usually end up with a similar looking image as you did, but I thought I'd give it a stronger stretch and a bit more saturation. But perhaps I over did it a bit

All my editing was exclusively with levels/curves/saturation/colour balance in PS, need to work on using masks etc a bit more. 

with dithering, is it just a case of moving the camera a touch every so often? Will that not cause issues when stacking? I'd be worried about risking PA issues...but perhaps if I did it every 20 minutes or so, and checked PA each time, might actually ensure a better PA result in the end. Food for thought!

cheers guys

[alacant]

44 minutes ago, Iem1 said:

is it just a case of moving the camera a touch every so often?

600d, so no. Randomly up to about 15 pixels after every frame. Most astro capture apps will do it for you.

47 minutes ago, Iem1 said:

I believe I took dark frames

600d, so better without.

47 minutes ago, Iem1 said:

definitely did not use flats

Flat frames aren't really optional.

HTH

[Iem1]

29 minutes ago, alacant said:

600d, so no. Randomly up to about 15 pixels after every frame. Most astro capture apps will do it for you.

600d, so better without.

Flat frames aren't really optional.

HTH

Thank you.

Quickly read up on dithering, seems like it will be something I delve into properly when I have a guiding system in place and use software with my setup.

At the moment I have no guiding and don't use any software, Just a DSLR and a intervolemeter. A very simple setup.

Apparently, I read the fact that I have no guiding basically means I am dithering to some degree due to general drift, That each frame will have shifted slightly from the last ..a point to the 'pros' section of not having guiding, automatic, uncontrollable dithering lol

I do not much like the thought of manually scooting over the FOV of the imaging rig 120+ times a night with my 60 second exposures! Yikes!

Doubt I will continue adding to the data I have already due to that star trail, I assume that if  trailing is impacting the star detail, its also detracting from the galaxy detail/quality. Think I will start a new Andromeda project, 30 second subs to try Stamp out trailing completely, try achieve ~4 hours of total integration over two nights, full calibration frames. Hopefully produce a sharper/cleaner image. Will update here as I go!

[alacant]

21 minutes ago, Iem1 said:

I am dithering to some degree due to general drift,

Unfortunately not. For dithering to be effective, it requires camera movement between frames only. Not constantly during them.

As noted by @ONIKKINEN, this results in streaks/lines of noise in the direction of the drift.

Cheers

[AstroMuni]

14 hours ago, Iem1 said:

Just looking for some opinions on some work I have been doing with Andromeda data. (Its about 1 hr 45 of 60 second subs, unguided)

That looks amazing. Love it 👍🏽

It does have a blue tinge and you should be able to go into PS and adjust the blue curve to reduce that effect.

Edited August 10, 2021 by AstroMuni

[Gonariu]

10 hours ago, Iem1 said:

Grazie Gonariu!

Sono fortunato ad essere in grado di raggiungere siti decenti con cielo scuro, quell'immagine è stata scattata nei Brecon Beacons (Galles, Regno Unito) che apparentemente è un 3-4 bortle. Va bene, dato che non ho filtri per l'inquinamento luminoso ..Anche se penso che la luna fosse a circa il 70% e abbastanza luminosa durante quella sessione di imaging. Devo ancora sperimentare l'AP senza la luna (nella regione di Sadr ho fatto circa la metà delle immagini prima che la luna sorgesse) 

sperando di poter uscire questa sera e riprovare senza alcun chiaro di luna, sia bello vedere la differenza.

I wish you good observations and beautiful photographs! If poltronite doesn't win me after dinner I see Jupiter with the Vixen 102M that I bought myself; I do not think it is a suitable day for either the planets or the deep-sky because there is a wind from the south that this morning made the sea agitated and the sky is certainly dull due to the suspended Sahara sand (apart from the light pollution of Cagliari).