Problems processing my 1st M31

[Moonshed]

I have taken my first DSLR DSO and opted for an image of M31. I took 30 lights at 90 secs on 800 ISO, 7 darks and 15 flats. After stacking in DSS, no processing used, I got this image,

image.tiff

I then loaded it in Photoshop and that's where the problems started, I have never used masks or layers, so at a bit of a loss really. The best I could do using only the basic stuff is this.

 

 

I do do not need to be told how awful it is, I do know, honest!

So seeing where I am at is there a really good tutorial on YouTube anyone can recommend? I have looked at a few but they were either way too advanced for a beginner like me or just too basic to be any help.

The thing is I have no idea if my DSS stacked image is okay and worth processing until I get it right, or is it in fact too poor to bother with?

As always your advice would be greatly appreciated.

Keith

[Ouroboros]

I found Doug German's videos on basic processing of astro images in Photoshop was good starter.  

 

[Moonshed]

9 minutes ago, Ouroboros said:

I found Doug German's videos on basic processing of astro images in Photoshop was good starter. 

 

Thank you for that, I looked at the first 5 mins and felt this was more like the sort of thing I am looking  for.

Hopefully in a few days I will post my finished image and you will say "Oh wow! That is just so fantastic!!! " Or, "Oh well, at least I did try to help the poor soul".

Thank you. Watch this space, or not if you are smart.

Keith

[Oddsocks]

PM sent with a few basic articles in pdf format, should be in your SGL inbox shortly.

Main problems with your image is slightly poor focus which has robbed a lot of the detail and some strange reflection-like artefacts.

Try processing a stack without flats and a stack with flats to see what difference it makes, I suspect your flats will be the problem, if you look at your flat frames alone there should not be any "structure" other than dust "bunnies" (donuts) and a gradual change in intensity across the whole frame but in your DSS calibrated image there are some odd semicircular structures in the background and I can only think they may be flat induced.

If your camera has a viewfinder window mask, usually in the accessory packet or attached to the lanyard make sure it is fitted to cover the viewfinder while you take astro pictures to stop light leaking in to the camera via the viewfinder

(some cameras have a little lever by the viewfinder window that pulls a shutter across the viewfinder - some have a detachable clip-on mask)

 

 

 

 

 

[Moonshed]

Thank you Oddsocks, looks like there is some very useful stuff in the articles you PM'd me, I will have a good read tomorrow, with pen and paper to hand for note taking!

I will try what you suggested re the flats, although from memory they appeared fairly even. I suspect your remarks re the camera viewer may be more relevant, I use an angle viewer that clips onto it for easy access and think it may be picking up the light from the laptop that is positioned close to the rear end of the scope, something that I had not previously considered. Next time I will ensure it's covered.

Regarding focus, yes I do find that problematic and have purchased a Bahtinov Mask. However, I have tried it just two or three times but have not been able to find a bright star that I can actually see through the scope with the mask in place. I will try again because as you have said correct focus is essential.

Thanks again

Keith

[Oddsocks]

1 hour ago, Moonshed said:

I have tried it just two or three times but have not been able to find a bright star that I can actually see through the scope with the mask in place.

That is often the case, for those of us using dedicated astro cooled CCD cameras we don't get a viewfinder at all!

The usual method is to increase the camera ISO setting, slew the scope to a bright star and use the camera live view, or in some cases video mode, not the view through the viewfinder, to centre the star and then place the mask over the telescope or lens.

If you still can not see the star with the mask in place mask in live view then change to continuous shooting mode at say five seconds per image with a small to medium resolution set in jpg format and make small changes to the focus every ten seconds or so while looking at the last-image-display, then once focussed lock up the focuser and make a last check that nothing has moved, remove the mask from the telescope or lens and slew back to the object for framing while still in live view, video mode or continuous shooting. When happy then stop live/video/continuous mode, change the iso setting back to the best for your camera in the range 800-1600 and set the image format back to max resolution and raw file save, delete all the focus images on the memory card to make space and then begin the acquisition sequence.

 

[Moonshed]

6 hours ago, Oddsocks said:

That is often the case, for those of us using dedicated astro cooled CCD cameras we don't get a viewfinder at all!

The usual method is to increase the camera ISO setting, slew the scope to a bright star and use the camera live view, or in some cases video mode, not the view through the viewfinder, to centre the star and then place the mask over the telescope or lens.

If you still can not see the star with the mask in place mask in live view then change to continuous shooting mode at say five seconds per image with a small to medium resolution ...

 

That sounds very helpful, I will try that next clear night and see if that helps, I was beginning to think the mask was a waste of money but knew it couldn't  be as so many people swear by them. Regarding keeping the camera viewer covered when taking images I had a look to see if there was cover provided. You mentioned it may be attached to the camera strap it it wasn't. Then I looked closer. It was threaded onto the strap and I had no idea it was there, I thought it was just a part of the strap adjustment clamp, what a numpty! ? Anyway, no more stray light will be entering the camera, the focus will be pin sharp, all I need is a dark clear night again.

BTW The image you made looks so much better than mine, I will try again.

Thanks for all the help, much appreciated.

Keith

[spillage]

Hi Keith,

 

I also have the 1100d and you should be able to see a star with live view it may be worth slewing to a bright start and centering this in live view then putting the mask in place. Then making the adjustments needed. On the 1100d you should be able to turn off the display. Are you using a laptop or pc with live view when taking your images?

cheers

Spill.

[baggywrinkle]

I have an old 450D which gets used from time to time and it has no live view. I did try one of those RA clip on viewers.....don't bother the image is still too small to get decent focus.

That is why I like the 650D, live view with up to 10x magnification. You still need a bright star to focus on first and then lock the focuser.

[wornish]

As already said by oddsocks you have some artefacts in the tiff file you shared.  Some were created in the DSS stacking process at the left and bottom edges of the image.  These need to be cropped out before doing any further post processing.

The other artefact that curves across the image is possibly caused by your flats which a quick stack without them will confirm or not.  They could also be caused by light pollution, if you open just a single light frame and stretch using levels you should be able to see if thats the cause.

 

Stacking in DSS is best done without letting it do any auto white balancing or auto calibration.  Make sure RGB Channels Background Calibration and Per Channel Background Calibration are disabled when processing DSLR shots, it gives you more chance of getting a better image in post processing. 

 

Not sure what version of PS you have but I agree with the other posts on here that you need to view some of the YouTube videos that take you through the steps needed.  It is just not possible to get the best out your images in photoshop without using layers and masks.

One low cost way to speed things up is to use something like "Annies Astro Actions"  which automate a lot of the common steps.  It does work.

You can get it here. http://www.eprisephoto.com/astro-actions

Hope This Helps.

[Moonshed]

2 hours ago, spillage said:

Hi Keith,

 

I also have the 1100d and you should be able to see a star with live view it may be worth slewing to a bright start and centering this in live view then putting the mask in place. Then making the adjustments needed. On the 1100d you should be able to turn off the display. Are you using a laptop or pc with live view when taking your images?

cheers

Spill.

 Hi Spill, I am using a laptop. Previously I have not been able to get Live View to work in APT so that caused problems in framing and focussing but I have got it sorted now, it was because my 1100D will not give Live View when the intervalometer is also plugged in. I will try it the next clear night.

cheers

Keith

[spillage]

Ah..If using your laptop and scope ditch the valometer and use eos utilities via usb to set up your exposure times and number or exposures you want to take. You should find it much easier. Just make sure you set the exposure time to bulb mode and click on the timer icon at the bottom of the program. When setting your time till next exposure I find adding an extra 5 seconds on top of you exposure time is enough. If this make sense.

[Moonshed]

Hi Wornish, I will check out my flats as suggested. The link you gave me to Annie's Astro Actions looks interesting, I will most likely buy it, looks like a good system. Thanks for the info.

Cheers

Keith

[Moonshed]

15 minutes ago, spillage said:

Ah..If using your laptop and scope ditch the valometer and use eos utilities via usb to set up your exposure times and number or exposures you want to take. You should find it much easier. Just make sure you set the exposure time to bulb mode and click on the timer icon at the bottom of the program. When setting your time till next exposure I find adding an extra 5 seconds on top of you exposure time is enough. If this make sense.

Yes thanks it makes sense, I use a 5 second gap between subs and it works fine. However, I cannot use APT while EOS Utilities is also loaded, APT just won't have it and tells me so. Anyway, I intend to focus on a bright star using Live View and the mask, then going to the DSO I want to image and framing it, then plugging in the timer and that's it. Hopefully.

[rubecula]

Hi Keith,

You shouldn't have to use an intervalometer at all.  I would have thought that APT would handle all that for you.  I don't use APT, instead I use a similar product BackyardEOS.  With that you can control all aspects of image taking with a Canon DSLR - ISO, exposure, interval between shots, mirror lock-up etc.  I'm sure that must all be possible with APT.

[Dbswales]

If you can possibly use APT, it lets you zoom in onto the chosen star and makes the whole focusing/star spikes a doddle. APT will also do the separate exposure plans, lights, darks, bias, flats so you don't even have to go near the scope during the process.

I read somewhere that when your laptop recognises the camera, right click it where it appears in your taskbar and close it, after that APT should run ok. There's loads of handy and valuable features on APT so if you can get them to work together, its makes it so much easier.

Good luck.

[wornish]

4 hours ago, Dbswales said:

If you can possibly use APT, it lets you zoom in onto the chosen star and makes the whole focusing/star spikes a doddle. APT will also do the separate exposure plans, lights, darks, bias, flats so you don't even have to go near the scope during the process.

I read somewhere that when your laptop recognises the camera, right click it where it appears in your taskbar and close it, after that APT should run ok. There's loads of handy and valuable features on APT so if you can get them to work together, its makes it so much easier.

Good luck.

I know APT is very good but I would love to know how it can do what you claim without you going near the scope. 

How does it put the lens cap on for darks and biases, then how does it find a white target for the flats ?

Am I missing something ?

 

[Ouroboros]

20 hours ago, baggywrinkle said:

I have an old 450D which gets used from time to time and it has no live view. I did try one of those RA clip on viewers.....don't bother the image is still too small to get decent focus.

That is why I like the 650D, live view with up to 10x magnification. You still need a bright star to focus on first and then lock the focuser.

That's odd. My 450D has live view.  I slew to a bright star, switch on live view, use the x10 to expand the star and then focus while turning down the exposure duration until I can only just see the star as I scan the focus in and out through the sweet spot.  Did you mean 350D?

A problem is that in tightening the knob that fixes the focus position often puts the telescope out of focus. It's a matter of tightening a bit, refocusing, tightening a bit more then retightening until the focus assembly is held tightly at best focus. 

[Dbswales]

13 hours ago, wornish said:

I know APT is very good but I would love to know how it can do what you claim without you going near the scope. 

How does it put the lens cap on for darks and biases, then how does it find a white target for the flats ?

Am I missing something ?

 

Sorry, what i mean was that you could plan, edit and shoot all your exposures from the APT software with no need for going near the camera or a intervalometer. You'll obviously have to manually fit the lens cap to do the darks and biases.