M45 , M33 , Help me stars are enormous !

[Steve Ward]

Spent about 2 1/2 hours on each of these last night , 75-300 on the 1000D + HEQ5Pro ( 3min subs all night)

These are first tweaks in the back-end of DSS only , I intended them as a trial for dedicated nights on each target with the ED80 + F/F.

Can I expect to get smaller stars with the ED80 , especially the ones in M45 , they're so bright that they grow enormous when going long to catch the nebulosity . . . ?

I'm quite pleased with the M33 as I've never caught more than a hint of it visually.

M33.

M45.

Shred away folks . . .

Steve.

[rfdesigner]

Are you using a UV/NIR suppression filter?

Refractors, even good ones, will only focus a narrowish band of wavelengths to a point, outside that will not be in focus, I had a look at your image and the blue channel stars are much fatter than the green or red

Derek

[pete_l]

Spent about 2 1/2 hours on each of these last night , 75-300 on the 1000D + HEQ5Pro ( 3min subs all night)

These are first tweaks in the back-end of DSS only , I intended them as a trial for dedicated nights on each target with the ED80 + F/F.

Can I expect to get smaller stars with the ED80 , especially the ones in M45 , they're so bright that they grow enormous when going long to catch the nebulosity . . . ?

I'm quite pleased with the M33 as I've never caught more than a hint of it visually.

M33.

M45.

Shred away folks . . .

Steve.

Nothing to shred!

I'd be very happy with those. I believe that zoom lenses are always a bit of a compromise for astro photography, due to all the extra elements they contain. So yes, I'd expect that with a telescope (or even a prime lens) designed and optimised for the job, you'd get better images. Plus, there are tools available to reduce the amount of "bloat" in stars.

Here's a cropped example I took some years ago with a 20D + 200mm, stacked and rather over-processed

... at least I would have put an image up, but the forum software is being obstructive about the file's name <sigh>

[Steve Ward]

Cheers guys,

The Canon zoom is pretty poor , I had the Sigma 70-300apo to start with , great glass but so 'loose' in the zoom action that it would creep when aimed over 40 degrees up !

Have been trying to translate PS starmasking into Gimp as I only have Elements in PS and it's missing the bits I need.

Know what to do now , it's just a case of figuring out how.

Will get there in the end.

Steve.

[rfdesigner]

Steve

Sorry, got hold of the wrong end of the stick.. so you're using a camera lens not the ED80.

Did you use it at maximum aperture?.. it's usually advisable to knock lenses down a notch or two to tighten up the stars (even very expensive ones)

Derek