The Pipe Nebula in Ophiuchus - 1st Attempt

Keith, the best startegy for darks is to:

1. Take them at the same exposure duration and temperature as your lights
2. Take a few of them - try 5 (arbitrary number) to begin with
3. Median combine the darks (you may need one of the freeware packages to do this - I'm not familiar with them but I think registax might be able to do it)
4. Subtract this composite dark from your image. Again, I think Registax can do this but try photoshop - there's a few hoops in ps to go through but it can be done.

That should see you right.

By the way, nice image. Your images always look a little dark on my monitor - do you have yours calibrated?

Cheers

Dave McD

This is excellent work! I also have an interest in dark galaxies and suggest you look up the SNAKE NEBULA (B72?) which is equally stunning.

Question for you: is the reddish tint on the right side of the photo (middle of right edge as well as the bottom right corner) amplifier glow from the camera or is it natural? At the same time, a dark frame would have helped if it is indeed amp glow.

Anthony, I know og the snake nebula, I've seen it in better shots than this and is absolutely stunning! I think there is a bare hint of it there, but i'm not so sure, i'll look skyatlas 2000. As for the reddish glow to the right, you're right, it's ampglow from the camera, how do you add a darkframe? I know how to take one, but how is it added???? In photoshop???

Hi Keith,

We take a dark frame for the same duration as the RGB frame and under the same environmental (temperature) conditions. We then layer the dark frame on top of the RGB frame and then have Photoshop keep the difference between the two. This, in effect, will subtract the dark frame from the RGB frame and correct for hot pixels, random noise and amp glow.

Anthony.

Dave G, damn, so many globulars, I knew of a few there, but that's a lot, can I post it to the all-ireland sky project?? It's about time we started on this, It wouls be a good start i think

You can do anything you wish, its your image. Hopefully I can add a few of my own soon now I got my new scope gear!!

Your images always look a little dark on my monitor - do you have yours calibrated?

Dave, I don't have my monitor calibarated, do you think it a good idea to do this?

Yourself and anthony, thanks for the darkframe techniques, I knew of the concept, but did'nt know how to do it in practice

Keith..

Hi Keith - for any serious work in colour graphics, your monitor should be calibrated. Of course, graphics will then look natural on your own calibrated monitor but viewers with uncalibrated monitors are at the mercy of the gods...

You'd be surprised though, the more experienced imagers all have their monitors calibrated to some extent.

Now, the only method I use is to use the calibration routine in Photoshop. I know there are more complex methods that can be used but I don;t think I'm into it that big. yet... Dave Power copuld probably jump in here with some advice.

If you have photoshop, Adobe Gamma will be in the control panel or in the 'goodies' folder of photoshop. It could also be elsewhere - check the help file. If you don't use photoshop, I'm not sure how it can be done. There must be some freeware out there that can help....

Good luck!