M42 second attempt at imaging and some questions.

[vanwonky (Dave)]

My second attempt at imaging here after much wrestling with polar alignment and guiding. This is shot at 300s @ 800iso. I did take some 120s,60s and 10sec exposures as well but I am just getting my head around Nebulosity for stacking etc so I haven't used them yet.

I am OK with the result for what it is. I would like to see a bit more blue in some of the nebulosity but can't pull it out if it is there at all. I did grab the core from a 10sec exposure to mask the blown out core but I think it looks dodgy. The stars seem to be getting some oval in them but would like opinions please. I did (again) run out of time to get more (many more) exposures which of course would have helped the final image. I guess my camera has it's limitations (well depth?) with longer exposures as well. No flats or bias yet as I am just building my light box.

Questions:
1) At 300s the core is totally blown out as you can see in the original unprocessed image. Should I be taking shorter exposures (many more!) instead. If so will that still show up the fainter details if stacked or can that only be achieved with the longer exposures and then masking with the shorter ones.

2) Still need to read up on it but will stacking (which ever program you use) stack exposures of different lengths to any benefit?

Lights: 3 x 300s @ 800iso
Darks: 3 x 300s @ 800iso

Sharpstar 106mm
Canon 350D Modded

Cheers
Dave

[niko]

Dave,

what an excellent effort - colours look great and you certainly have lots of data there for the number of exposures.

Not an expert by any means but a few comments

1. seems to me the focus is a bit soft. do you have a bahtinov mask to assist you with focus?
2. yes, at 300 sec the core will be blown out. take some shorter exposures (as you have done) and mask them on the longer exposure
3. take more exposures - say 10 of each longer and shorter and stack them
4. I use Deep Sky Stacker - it will stack the dark and subs together. Do one for the long and one for the short then use Photoshop to merge.

that's my 2 cents worth

awesome effort if that's only your second attempt

well done

niko

[scagman (John)]

Hi Dave, That looks really good, I'm no expert either, only just made it to beginners level, so I cant give any advice than would be any good.

So well done.

Regards

[vanwonky (Dave)]

Originally Posted by niko

Dave,

what an excellent effort - colours look great and you certainly have lots of data there for the number of exposures.

Not an expert by any means but a few comments

1. seems to me the focus is a bit soft. do you have a bahtinov mask to assist you with focus?
2. yes, at 300 sec the core will be blown out. take some shorter exposures (as you have done) and mask them on the longer exposure
3. take more exposures - say 10 of each longer and shorter and stack them
4. I use Deep Sky Stacker - it will stack the dark and subs together. Do one for the long and one for the short then use Photoshop to merge.

that's my 2 cents worth

awesome effort if that's only your second attempt

well done

niko

Thanks Niko. I did use a Bahtinov mask but admittedly did not check the focus again during the night as recommended so it might have gone out. Or of course it wasn't exactly right! The 350D doesn't have Live View which does make focussing a little harder. Maybe the tracking was a little off? I guess that would give a softer result as well?

Originally Posted by scagman

Hi Dave, That looks really good, I'm no expert either, only just made it to beginners level, so I cant give any advice than would be any good.

So well done.

Regards

Thanks John - appreciated. With the quality of astrophotography in this forum I think I might be posting in the beginners forum for quite some time!