Putting my new CCD to the test : M13

[Catanonia]

Managed to get a few hours on M13 during the short night.

This was a test of the QHY9 mono + 2inch LRGB filter wheel and the lumicron OAG all attached to the Skywather ED120 Diamond Refractor mounted on NEQ6Pro mount.

Guiding was OAG / QHY5 / PHD

Processing in Maxim and CS3, individual channels processed and re-merged.

LRGB 45:25:25:25 in 5 min subs

Hope you like it.

Cat

[SlipperySquid]

It's a bit good innit

[SkyHermit]

Well if that's a test, can't wait for the real thing. One day I'm gonna do pictures like that!

[shaula]

stunner! loving that!! nice work!

[ollypenrice]

Yes indeed, a hell of a start! Stunning resolution, tight little stars and colour on its way. What more could you ask?

Olly

[Space Cowboy]

Wonderful image! Making very good use of all that kit for sure!

[Coco]

Cat... is this cropped or as-is?

I'd like to scale it against my 40D DSLR

If its cropped can you post an original Luminance

Cheers

Guy

[Zapp]

I love this image, the stars look 3D and the detail is amazing. One thing I noticed, it might just be my monitor, but I can see a black line on the top left along the path I have indicated with some crude paint skills.

Thought I should mention it in case it's an issue with the equipment.

[ollypenrice]

Hadn't spotted that. Curious. Did you Ps out a satellite, maybe?

Olly

[Coco]

I love this image, the stars look 3D and the detail is amazing. One thing I noticed, it might just be my monitor, but I can see a black line on the top left along the path I have indicated with some crude paint skills.

Thought I should mention it in case it's an issue with the equipment.

well spotted.. wonder what that is:)

[Catanonia]

Cat... is this cropped or as-is?

I'd like to scale it against my 40D DSLR

If its cropped can you post an original Luminance

Cheers

Guy

Cropped mate, here is an original sub in this thread

http://stargazerslounge.com/imaging-discussion/105352-yes-got-working-oag-qhy9.html

The line is a satelite or a small plane that must have sneaked into the subs and got highlighted with the stretching level work. Hadn't noticed it. Didn't take enough subs for DSS to remove it

[Catanonia]

mmm, not sure if the line is on the updated version. Might have cuaght me between edits

[ollypenrice]

Just had another look at this 'cos were were on M13 last night down here. Boy, sharp little stars from that 120. Superb.

Olly

[Catanonia]

Thanks Olly, When I took the 1st sub I thought, mmmm, they look bloated even though I focused with the mask on Vega.

Then re-focused on smaller stars and was surprised how far off I was.

So moral of story, yes cool down time changes focus, but more importantly, focusing on BIG stars perhaps is not the way to go.

[barkis]

A good point regarding focusing using a very bright star such as Vega. The star is still a point source, and merely an illusion that it is larger, but does brightness affect, or interfere with the true focus.?

The light is probably spread out by the atmosphere, even on a quiet night, so a misread of the exact focus is possible.

Has anyone else experienced focus difficulty on a bright star.?

Ron.

[ollypenrice]

I never use bright stars for final focus. I use Atik's FWHM measurement so the star mustn't be saturated. 'Small' ones are best. Also I use three second subs (unbinned) so that the seeing has a chance to be averaged out before the software tries to calculate a centroid for the stellar image.

However, I rather feel I should be listening to how Catatonia did it than waffling about my approach 'cos those darned stars are too good!

Olly

[Catanonia]

I never use bright stars for final focus. I use Atik's FWHM measurement so the star mustn't be saturated. 'Small' ones are best. Also I use three second subs (unbinned) so that the seeing has a chance to be averaged out before the software tries to calculate a centroid for the stellar image.

However, I rather feel I should be listening to how Catatonia did it than waffling about my approach 'cos those darned stars are too good!

Olly

LOL.

I take the following approach.

1. Align mount

2. Focus on a bright star to get it close, Vega for instance

3. Frame the image on target M13

4. 5 second unbinned with Bahnitov mask and zoom right in to get the smaller stars with perfect difraction spikes and lock the focus.

5. Take the 1st sub and check again with mask before continuing.