First DSO - any advice please?

[Sabalias]

Hi All,

My first attempt at imaging a DSO. I managed to get out on Saturday night for a short spell (time was constrained by having to be up at 0530 on Sunday morning). I was only able to take 8 usable lights of the dumbbell nebula in the time allowed and I played around with the output yesterday and this morning on Astro Pixel Processor. There is a focus issue here but does that explain the egg-shaped stars? I'm also wondering if it's flexure (I thought eveything was locked down tight but maybe need to check that in future). I'm using my 150PDS with an astro modified EOS 600D and a Baader MPCC (which I thought was the correct distance from the sensor). I also took several darks and I have some bias shots too, but no flats (I didn't have the time).  Any advice greatly appreciated.

The sky was quite bright even at the time I was taking the lights which is why I had to stick with short exposures - looking forward to earlier, darker skies😂

Many thanks,

Stu

[vlaiv]

This is very good for first DSO image.

I'd say that first thing to do is to check collimation of the scope.

Stars are not round and they change shape across the image and my first guess would be that scope is not quite collimated properly.

Second thing of course is to plan for flats in the future

[teoria_del_big_bang]

That really is a very nice image for a first DSO.
With the short nights at moment it's not best of times and yes you are clearly aware of some issues with star shapes, but I think everybody has some sort of issue to beging with and may take several sessions of tweaking things to get this right.

vlaiv is far more experienced than myself and has helped me many times so I would take his advice as the first step to getting the stars round across your image. There can of course be more than one issue that can cause this so you still may have some tweaking of distance between the MPCC and sensor but check the collimation first.

Steve

Edited July 19, 2021 by teoria_del_big_bang

[Sabalias]

16 minutes ago, vlaiv said:

This is very good for first DSO image.

I'd say that first thing to do is to check collimation of the scope.

Stars are not round and they change shape across the image and my first guess would be that scope is not quite collimated properly.

Second thing of course is to plan for flats in the future

Thanks Vlaiv. I did have some serious issues with collimation last week when I started using a concenter, it turned out to be focus tube alignment. I thought I had sorted it all out but maybe I missed something or the primary moved out of alignment a bit between my tinkering and imaging. For the flats I suspect I'll have to wait a little while for some longer nights and use the white t-shirt technique 😆 - here's hoping for clear skies in August and September!