Why is 80mm APOs most common for AP?

[alienf0rm]

Glad you like it. Thanks. It's an image which has grown over the years but it is Tak FSQ85ED/Atik4000 monochrome CCD in LRGB plus Ha blended with red. I combined an M42 shot at native focal length with a wider field shot through the 0.73 reducer. This enhanced the resolution in the core. Sub lengths were 11 seconds for the Trapezium, 50 seconds for the area around it and 10 minutes for the main field. The Ha would have been in 30 min subs from memory. The different sub lengths were combined using Layer Masking in Photoshop CS3. Total exposure time will be a lot, in the order of 15 hours or so.

Olly

Thanks for sharing you workflow. This sounds like a ridiculous question: for the 15 hours of exposure, what do you during that time? I mean, do you just set it to shoot automatically and then come back or do you have to be involved every now and then?

[Anas Albounni]

Glad you like it. Thanks. It's an image which has grown over the years but it is Tak FSQ85ED/Atik4000 monochrome CCD in LRGB plus Ha blended with red. I combined an M42 shot at native focal length with a wider field shot through the 0.73 reducer. This enhanced the resolution in the core. Sub lengths were 11 seconds for the Trapezium, 50 seconds for the area around it and 10 minutes for the main field. The Ha would have been in 30 min subs from memory. The different sub lengths were combined using Layer Masking in Photoshop CS3. Total exposure time will be a lot, in the order of 15 hours or so.

Regarding Ps and PI, I agree 100% with John, above. I couldn't manage without both and use them very much as John says he does. I would find trying to process a whole image in PI to be like tying my shoe laces with chopsticks. I rely on layers in Ps and make heavy use of the eraser to select what part of each layer I want to keep. In PI you have to use masks to do equivalent work in particular zones and the masks never go where I want them to go! But for colour calibration and flattening and gradient removal and losing green noise PI is king.

Olly

I see that i have a LONG way to go to have the proper equipment for AP, Thank you so much for the tips, Much appreciated, i still cannot get enough looking at your photo

PS (Photoshop) i know as I'm a graphic designer but whats PI?

I'm planning to use Equinox 66mm (focal length 400mm) for guiding, any recommendations for guiding camera? would Skywatcher Synguider be sufficient?

[laser_jock99]

Thanks Alan. The real point , though, is that you don't need a big scope for this kind of imaging. Here's the little fella who did the business.

Olly

Definitely a case of matching the focal length to the size of the object. Possibly many people fail to realise just how BIG some of these DSO's actually are in the sky? And, conversely, how small some 'popular' objects like M57 are in a telescope.

Certainly many of the large DSO's are a well within the realms of (or possibly even better suited to) a telephoto camera lens so you could argue that you don't actually need a telescope to start imaging DSO's!

[Earl]

Whilst i agree with matching the focal length I give speed priority personally.

[mikeobrien]

Especially with our lack of clear skies!

[Moon-Watcher]

All fascinating.  So the Esprit 80 ED PRO Triplet or the Evostar 80ED DS-Pro Outfit?  and why the BIG difference in price?

[Earl]

All fascinating.  So the Esprit 80 ED PRO Triplet or the Evostar 80ED DS-Pro Outfit?  and why the BIG difference in price?

colour correction is harder the achive with lenses the faster the system, this leads to a far more precice system requiring more work to make, and while spending more on the glass everything else gets a upgrade.