M42 Orion & Co.

[2020BC (Bill Christie)]

Captured another Orion last night.

I added to it the data from the previous night and here's the result.

The fishing line had to come off the front of the ED80 so that I didn't end up with two sets of diffraction spikes..

Exposure: 33 x 3 mins (over 2 nights) ISO 1600 (20 darks)
Camera: Canon 350D unmod
Scope: Orion 80ED (with crosshairs and UHC-S filter)
Mount: LXD-75 auto-guided
Guidescope: LXD-75 SN-8

[h0ughy (David)]

beautiful

[leon]

Stunning image. could look at that for ever.

Cheers Leon

[tornado33]

Well done, great colours, both in imaging and processing
Sccott

[Garyh]

Thats a nice image there Bill. You have smoothed out the image rather nicely with all those stacked frames!!!
Nicely guided and natural looking too!!.....
Cheers Gary

[xelasnave]

Excellent capture and process. You must be very happy with such a fine result.
alex

[2020BC (Bill Christie)]

Thanks, yes very pleased with how this worked out, particularly with an ED80 at f/7.5. I just wish I could get the collimation on my SN-8 sorted out once and for all. The secondary keeps moving (rotating in the corrector). I think the result on M42 would be even better with 8" of f/4 aperture but maybe not. Anyhow, having the SN-8 out of action again is such a pain... For me collimating the secondary on the Schmidt Newt is like having a tooth pulled... It's absolutely trial and error for me to fix this again. Ho hum...

[spacezebra (Petra)]

You should be pleased - what an excellent image.

Cheers Petra

[asimov (John)]

Stunning image. How did you control the central burnout with all the exposures being @ 3 mins each Bill?

I have an M42 image done with a GSO 8" F4 newt (& 20DA) if you want to see it for comparison sake.

I have been using a 5.5" F3.6 schmidt newt as well & yes, I had to adjust the secondary to get my collimation good. What a pain

[2020BC (Bill Christie)]

Originally Posted by asimov

Stunning image. How did you control the central burnout with all the exposures being @ 3 mins each Bill?

I have an M42 image done with a GSO 8" F4 newt (& 20DA) if you want to see it for comparison sake.

I have been using a 5.5" F3.6 schmidt newt as well & yes, I had to adjust the secondary to get my collimation good. What a pain

Because cameras and computer screens have a limited dynamic range (i.e. a limited range of brightness - darkest to brightest) the only way to deal with a burnt out core is to use a technique called Masking (or Compositing). What you must do is overlay the core (a short exposure that is not overexposed) over the top of the longer exposure which has the overexposed core. Basically you are cutting and pasting detail from a short exposure image into the burnt out core of a long exposure image. Software lets you do this in a seamless way. The result is that you have effectively increased the dynamic range in your image. I learnt this technique from Jerry Lodgriguss' excellent website. He and the other top imagers use this method. A few hours time spent touring through his website has saved many folks many nights of error and frustration. Click here to read Jerry's tutorial on Masking While you're there read through his other stuff, and check out his images. The guy's a legend.

[asimov (John)]

Thanks Bill. I know how to do all this (I have Jerry's CD ROM)
Just wondering how you did it as you didn't mention it in your original post.

Thanks mate.

[ving (David)]

lovely shot

[Ric]

Very spectacular Bill, great colours and detail

Cheers

[2020BC (Bill Christie)]

Asimov, hee hee. After all my waffle and checking through the image below in the original posting the core isn't actually masked. At the moment I have several different versions of this that I've processed in slightly different ways and posted on different sites. If we look again the image we refer to in the original post has a small burnt out region that hasn't been processed out. Looking through the original RAW stack the burnt core is exactly the same size as the posted processed version. Looks like it's just the way the camera rendered it with 3 mins in the ED80. The ED80 is f/7.5 and I did use the UHC-S filter - could this be the clue/info that you need? An 8" at f/4 @3mins will have more of the core burnt, even more so if it's unfiltered.

Attached here is an actual masked version with the core replaced with a 30 second exposure from the 80ED (UHC-S) (one that I nearly threw away because it was a focus test).

[asimov (John)]

Cheers Bill.

Yeah I tried the 2 different exposure times & the UHC-S filter last night. It was moon affected though so I guess I'm going to have to wait for the moon to bugger off.