M31 last night

[Bobby1970]

Must be at least 60 subs. Different exposures, a few darks. All with my st102. Sony A57 on my alt/az goto mount

Sent from my D6503 using Tapatalk

[tingting44]

very nice, flats will make the world of difference something to give a go next time

[pyrasanth]

M31 is a surprisingly difficult object for something so bright. I have found it a challenge to capture so you have done well. The use of flat frames aka calibration as mentioned will make a world of difference- it can be quite astonishing as to how many anomalies disappear. The image you have captured is very blue but that will improve with more subs & perhaps color calibration which is a whole new learning curve. I've just finished a project to photograph the core of the galaxy & it is a real pig to get the processing right as my thread demonstrates. It might be worth you having a look at the thread.

Your image is not the worlds best image but it certainly is not the worst I've seen either- so keep up the good work. 

[laudropb]

Nice image. Thanks for posting.

[Bobby1970]

What are and how do I do some flats? This is the first time I have done some darks I think. Lol.

Sent from my D6503 using Tapatalk

[xtreemchaos]

lovely image mate.  well done,  thanks for sharing charl.

[Bobby1970]

M31 is a surprisingly difficult object for something so bright. I have found it a challenge to capture so you have done well. The use of flat frames aka calibration as mentioned will make a world of difference- it can be quite astonishing as to how many anomalies disappear. The image you have captured is very blue but that will improve with more subs & perhaps color calibration which is a whole new learning curve. I've just finished a project to photograph the core of the galaxy & it is a real pig to get the processing right as my thread demonstrates. It might be worth you having a look at the thread.

Your image is not the worlds best image but it certainly is not the worst I've seen either- so keep up the good work. 

Thanks for the advice. What exactly are "flats"? And how do i get some ?? lol

I agree with what you say about the quality of the image, however considering the equipment i use i am really pleased with the outcome.

I keep debating getting an EQ mount but i am not sure i want the extra hassle of the set up tbh. Or the extra expense lol. 

It sounds was though i haven't even pushed the limit of the equipment i do have yet and will probably re-visit the same subject again at some point and try and use the tips given to achieve an even better final image. 

[pyrasanth]

What are and how do I do some flats? This is the first time I have done some darks I think. Lol.

Sent from my D6503 using Tapatalk

If you were to point your imaging system with a camera attached to either an evenly illuminated section of sky or even a piece of white card & take a photograph it is likely you would see specks of dust & vignetting at the edge of the frame. Vignetting looks like the image is faded at the edges. Dusts specks look like rings as in the flat below. After your imaging session- don't move anything camera or filters and take about 30 images at the piece of sky or card. You will need to get a saturation of 20-22K ADU (you can easily get software on the internet to measure this). When you stack all these frames together you will build a flat. This flat characterizes your image system & by subtracting this image from your subs if done correctly it will correct the optical imperfections of your system.

I have posted some examples below so you can see the principle.

First we start with our flat frame- this is one hundred images at 22K ADU saturation stacked on top of each other:  You can use less but it is better to get 30 plus. This is an L or luminescence frame. you will need a flat for each filter or one for your DSLR or OSC CCD camera. 

We then look at our image & see the vignetting & uneven field

We then subtract the flat from the image using software like CCDStack2 or similiar

The magic happens if your flat is correct. If you use separate filters you will need a flat for each filtet taken at the time of use as dust specs could be in different places on each filter. If you look at the flat you can see a ring- this is a dust spec corrected in the final image so it will not appear in your final image. I have seen some really dirty images cleaned up with good flats.

I would advise you do some internet research- there is plenty of help available & of course this forum if you get stuck. There is much to learn as this is a very simple example. To truly characterize your system you may need to consider BIAS & DARKS which are essential for some CCD cameras using Kodak CCD chips but not so important with Sony CCD chips,

Enjoy!

[tingting44]

Thanks for the advice. What exactly are "flats"? And how do i get some ?? lol

 will probably re-visit the same subject again at some point and try and use the tips given to achieve an even better final image. 

be nice to get a couple of hours worth of subs at least on this target, then your notice a big change, the more subs you have the easier processing will be, best of luck mate

edit, what length subs were you using by the way?

[Bobby1970]

25 sec.

Sent from my D6503 using Tapatalk

[tingting44]

25 sec.

Sent from my D6503 using Tapatalk

what does that make then.......15 mins total if my math is correct? thats not bad for such a short exposure, you could possibly get more out of processing, processing is by far the hardest part

[paul schofield]

Lovely image, wow.

[Bobby1970]

I had another go at this the other night, took about 200 subs this time. still not used any flats yet (really must do this). I know the framing is a little off too. But i am not fully convinced that this shot is any better than my previous one, even though i have many more subs. 

Thanks for looking