Do my stars look too big in this ?

[Entropy]

Hey guys.
Just a quick simple question, with a probably very complex answer
But... Do i my stars look big in this ?
This is as small as i could focus them, but they still look rather comical in size, is this just an artifact that is easily removed post ? or is my collimation WAY out or something ? (I do collimate before eqach imagining session, but i only own and know how to use a laser collimator).

I tried to think of a nice big bright, and therefore easy, target to shoot my first deek sky shot on, so i though. M42..... what else. Now i have discovered it is one of the more difficult objects to photograph.

Anyway this photograph is of m42 6second exposure at f5 through the red channel with a DSI pro. Guided.

http://i241.photobucket.com/albums/f.../m42R6sec1.jpg

Thanks for the help.

[[1ponders] (Paul)]

No that looks about right for a DSI. Do your filters filter out IR? If not you might want to consider screwing a UV/IR filter to the nose piece. Do you use a focusing aid? eg hartmann mask

[[1ponders] (Paul)]

Check out these shots taken with an ATiK 16IC (similar size chip and pixels) through an ED80 at f6
http://www.iceinspace.com.au/forum/a...4&d=1184826785
http://www.iceinspace.com.au/forum/a...4&d=1184540621
http://www.iceinspace.com.au/forum/a...5&d=1184540621

[ballaratdragons (Ken)]

Just a little bit of processing will help with the stars.

I hope you don't mind but I have cleaned the stars up in your image to show that mildly blobby stars are still ok. They can be fixed.

Here is your image with the levels adjusted, 3 layers made at varying levels, layered in HDR, and the stars cleaned up.

As you can see, you have the detail in there.

[Entropy]

I have been wanting to make a hartman mask for a while now, i might take the time to make one today, does anyone know where to get those plastic bucket lids discussed ?
As for the filters, i use the CCD colour filter set from Meade (LRGB) im not sure if these are sufficiently filter IR or not though.

Thanks for that ballaratdragons, that really does give me hope to keep going out there and trying again. I never suspected that that Trapezium was going to cause me so much trouble. I didnt even think of it to be honest. Im happy with my efforts then for my first deep sky shot.

Thanks guys.

[madwayne (Wayne)]

If you Google the web (not AU) "Hartmann mask generator" there actually is a website that will calculate the Hartmann mask for you, based on your telescope dimesnsions and prepare a PDF which you can print out. Cut it out, put it on some 3mm ply (cut out the mask and holes) and away you go.

I would give you the link but our Web Marshall at work was a Nazi in an earlier life and won't let me get to it to post it for you.

Enjoy!