My first attempt at DSO imaging

[BiffyFan83]

Hi everyone,

I thought I would share my first attempt at imaging on here as I have used this forum alot for advice from you guys. This is also my first post and would like to say thanks because I would have been clueless without this forum. I bought my scope around 3 months ago so I'm very new to astronomy. I have'nt had much chance to use it unfortunately because i live in the Uk lol I recently bought the dual axis motors with enhanced controller for my eq 3-2 and finally got to use it!! I would like feedback from you guys on my images on how to improve them espcially with regards to processing because i know even less about photo processing than i do about astronomy. Please be kind guys because I'm really pleased with what i managed to get and I'm not trying to win any awards for my images.

My set up is :

Skywatcher 150p on a eq3-2 mount

Dual axis motors with enhanced controller

Bahtinov mask

Canon 1000d ( unmodded )

Polar scope with new reticule

 

 

The final processed and cropped image - 112 30secs 800 ISO

[BiffyFan83]

I forgot to ask about this artifact which I get from my stacked image in processing. It looks like a ring in the middle of the image where its brighter than the outer edge. Is this just an effect from vignetting and if it is can i reduce or remove by taking flat frames?? Can it be removed in processing? I use GIMP for processing

[geordie85]

Well done on your first image. 

The effect your seeing is vignetting and will easily be removed with good flats.

I notice you've got quite abit of coma which a coma corrector will fix. 

We'll done

[BiffyFan83]

Thanks geordie. How do you actually take flats?? Do you have to take them at the same time you take your light frames or can you just take them anytime? Is coma the effect on the stars not been perfectly round??

[UKJay1971]

Well done - it's a great feeling when you see your first DSO appear in a stretch, isn't it! This will go through the basics of shooting calibration frames. You can make this a lot more complicated in the future once you get comfortable.

http://deepskystacker.free.fr/english/faq.htm

 

[BiffyFan83]

Thanks Jay. i see your from Wakefield, i live in Dewsbury not far from you. Yes it's an amazing feeling and I can't wait for the skys to clear so I can have a go at another target. I will have a look at that link, thanks. Does anybody have any suggestions for my next target? I really want to image the whirlpool galaxy but when I tried to find it a few weeks ago I was unsuccessful. Also, i would like to image the dumbbell nebula. Are these targets difficult?

 

[UKJay1971]

In the eastern skies, near the ring you have a few other nebula - the dumbbell nebula and the elephant's trunk nebula would be reasonably accessible (you don't tell me what camera you use). If you can look past the meridian then whirlpool is still accessible - it's just over the meridian in the west after 11pm. Other nebula, like the Crescent are achievable howeever more difficult on a colour camera or DSLR (see by two attempts below; the first was on a colour one shot camera, the second last weekend shooting in mono using a narrowband filter). Excuse the quality but they are highly compressed jpgs to allow me to post on here

[alacant]

4 minutes ago, BiffyFan83 said:

suggestions for my next target?

Another planetary but bigger? It rises a little later than the ring: m27. HTH.

[Astrosurf]

Great first image! That was my first target too. The egg-shaped stars are caused by trailing. You'll need to either get better polar alignment or reduce your exposure time a little. Is your polarscope reticule aligned to the mount? I don't know if your mount can accommodate guiding, but the DARV drift method of polar alignment should help:  

https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760

There are a lot of posts on here about different methods of taking flats (I don't do them as I use the GradientXTerminator plugin in Photoshop). Try a search. Start a new thread if you can't see anything that helps.

Alexxx

[BiffyFan83]

nice images jay. I'm using a canon 1000d dslr. only cost me 60 quid on ebay!! The flash doesnt automatically come out but can be manually pulled out. Doesnt matter though as I bought it purely for astrophotography. i think i will have a go at M27 alacant. Do you get better results if you take different exposure lengths and then layer them?

[Astrosurf]

As your camera is unmodded, you won't pick up much of the emission nebulae as the filter in your camera blocks much of the hydrogen alpha (Ha) light that they emit. Reflection nebulae are fine.

The dumbbell neb is a great target as it's bright. Also have a go at globular clusters but the stars must be pin sharp so try getting your polar alignment as good as possible and try out different sub lengths..

[alacant]

1 minute ago, BiffyFan83 said:

Do you get better results if you take different exposure lengths and then layer them

Unless it's something with very bright highlights, I don't think so. If you want to have a go at high dynamic range, you can take the same stack and layer different stretches. HTH

[BiffyFan83]

Thanks astrosurf!! I did try align my polarscope but i wasnt sure if it was done correctly. I had a go at it today and it did look like it wasnt done correctly before i took those images of the ring nebula. I also checked my collimation again today and that also appeared to be abit out even though when i first did it i thought i had got it right lol i guess you get better at it the more you do it. Im doing it unguided at the moment as ive run out of spare cash ( spent over a grand already!! ) but i do plan on guiding in the future.

[BiffyFan83]

Alacant, Do you mean a target like the cat's eye? I was looking at some images today and they had taken different exposures because of the brightness of the centre and the faint detail of the outer edge. I just wondered if i could improve images of other targets using the same method

[BiffyFan83]

Ive been thinking about globular clusters as ive seen some really cool images of them. Do you have any suggestions which ones? Ones that are quite easy to find if possible lol

[UKJay1971]

Use Stellarium to plan your shots - you can input your camera details (sensor and pixel size) as well as your scope's focal length etc. This will let you then see how your shot might look. The Cat's Eye nebula is quite small (then again, so is Ring Nebula) so it might not be as worth it as you hope.

For polar alignment, I use Sharpcap (£10 a year subscription and worth every penny to me). That generally gets me close enough to 5+ min subs.

[alacant]

18 minutes ago, BiffyFan83 said:

Do you mean a target like the cat's eye?

Hi. Yeah, that's it. Anything -there aren't many I don't think- where something overexposes if you stretch for the dim stuff. The core stars in the Orion nebula are famous for only being visble in a HDR layer. HTH.

[Astrosurf]

Objects with a high dynamic range are ones with very bright to very faint regions, like the Orion nebula. I don't use GIMP for processing but in Photoshop I use a Layer Mask to blend two or more images. I don't know if that's possible in GIMP.

Have a look at DSO Browser for good DSOs. It gives their magnitude. Compare them with the Ring neb to give you an idea. And look at Stellarium for the object's details too. M13 is a lovely glob.

https://dso-browser.com/

[SilverAstro]

On 27/06/2017 at 11:46, BiffyFan83 said:

 Can it be removed in processing? I use GIMP for processing

In GIMP in this case (edit : where there is no extended nebulosity) ** yes.

Duplicate a layer then go to Filters > Blur > Gaussian Blur >  choose size ( or maybe radius depending which version of Gimp) of about 1/5 0r 1/3 pixels of the image.  Change layer mode to subtract. Then in Image choose Merge Visible.

** only works if there is no large scale nebulosity in the image, (as in this case) else you will destroy that as well, hence the 1/5 to 1/3 caveat on the low frequency components in the image. Otherwise goto IRIS (free also )

 

[spillage]

For you flat and bias have a look here. There are better detailed websites but I have found this is fine.

Cheers

Spill.