Big scope fever. Is big aperture only emptying your wallet?

i would say the asa shows slightly more detail but the difference is very small

Slightly?  The difference looks significant to me.  I had to check you didn't have a joking emoji 

andrea tasselli:
There is a vast ocean of difference between the two and no offence to Timothy, which is still a gorgeous image (the image, not Timothy although he might be as well...). Or it is just trolling?

No trolling. I think the differences are very small for the aperture difference of an 130mm and an 600mm scope. 
Lets assume diminishing returns moving up further using bigger (earth based) scopes. If that is how close a 130mm apo will bring me to an 600mm scope, how far away can a 10inch or 12inch scope be?

There is clearly a rule of diminishing returns here. Especially if the goal is to take aesthetically pleasing pics. The pic from the big scope is not 4 times better. But it is better.

The images look similar at first glance, but there is much more fine details in the image from the big scope.

Timothy has the same 130mm scope as I - so by default I like his pictures :-) and his processing skills.

but have to agree on the earlier comments, not a comparison and not at all to compare is the light gathering power. 

there are lot very good software tools out these days improving picture quality and sharpness but still the asa collects over 20 times (!) more lights than the 130 mm. 

without the intention to open this „pandora box“ a good quality 130 mm refractor can easily stand a comparison with an 8“ or even 10“ reflector in terms of details and contrast but the refractor then normally is the way more expensive option in this comparison.

but not to compare to a 600 mm scope.

andrea tasselli:
Which you just did. And of course, not.

 In the context I have to admit that I can’t wait bringing my 14” Newtonian to my spot and start imaging with it.

andrea tasselli:

Alex:
without the intention to open this „pandora box“ a good quality 130 mm refractor can easily stand a comparison with an 8“ or even 10“ reflector in terms of details and contrast but the refractor then normally is the way more expensive option in this comparison.

Which you just did. And of course, not.

Would you mind showing me a picture of the trifid taken with an 10 inch scope showing that much more detail than the 130mm scope that you feel „and of course not“ is the right answer to this?

Would you mind showing me a picture of the trifid taken with an 10 inch scope showing that much more detail than the 130mm scope that you feel „and of course not“ is the right answer to this?

That's a trifle more involved, isn't it? You want to compare them side by side not "some refractor" there and "some other reflector" elsewhere sometime else. That's the bare minimum basis of any meaningful comparison. But there is more to it, I can guarantee that.

I agree with everyone above, the 600mm image is clearly the winner in terms of detail and resolution. Look carefully at the lower left corner, there's a world of difference there. That's said, the difference isn't as great as one might suppose from just aperture alone. You have to remember that the seeing is a great leveler here. If these two telescopes were in space the difference would be much greater, but they are not. Large apertures in this size range will always be limited by the seeing. A 600mm scope in theory can resolve down to about 0.20 arc/sec. when was the last time you saw seeing that good, my guess is never. You're taking that starting resolution and putting it through that low pass filter we call the atmosphere and most of the damage happens in the first 1/10 of a second. If both of those scopes had imaged the Moon or Jupiter, the difference would be night and day, no comparison. That's because, unlike deep sky, lunar and planetary imaging techniques allow you to go a long way to recovering the actual resolving power of the aperture, given good enough seeing. These techniques are not yet applicable to deep sky/long exposure imaging. If they were, you'd be totally blown away with what the large aperture can deliver but we're not there yet. With larger apertures in deep sky imaging, you can and do get better detail but the main advantage is in the light gathered. The brightness of an image on the sensor at F/4 is the same, regardless of aperture but the 130mm f/4 will be imaging at an EFL of 520mm, the 600mm will be at 2400mm. This delivers a much larger image at the same brightness.

Hi Andi, how would you scale the detail level between those two scopes? there's is a different amount of sharpening applied, maybe some HDR treatment also.

But if the sensor is suitable you wil get more details for sure that's just math.

If you take Rayleigh or Dawe's formula there's no point in discussion.
Smallest detail resolved with Dawe's
TOA130: 0.89 arcsec
ASA 600: 0.19 arcsec

I live in the same skies as some Wolfgang's telescopes, seeing on average is 0.5" but drop down to 0.2" of course in a "normal" skies such diamater will resolve as much as the sky allows…

On a philosophical point of view it's up to you where your expectations are and I totally respect your point of view of not seeing the point of going big. but I invite you to check one raw files of both under the same sky, it will be for sure obvious which is which even between a 12 inch and the TOA.

I'm flattered to have any image of mine compared favorably to even the worst image Wolfgang has ever taken. But I have to agree the Wolfgang's image is far better. And he got his superior shot in half the time I got mine. When it comes to telescopes, it's definitely the size that counts. Wolfgang is also in a different league from me when it comes to knowledge and processing skills.

I'm certainly no professional--just a retired unfrozen cave-man lawyer with lots of spare time to mess with astrophotography. Still, I'm ecstatic over the results the TOA delivers. It's damn sure the best scope I've ever used. It will never deliver the same results as a great 24" or 1.5m reflector, but I couldn't possibly be happier with the results it gets. 

I'm pretty certain, however, that there is a point of diminishing returns for people on a budget. I spent the first couple of months of the summer framing up the Crescent with all my scopes and compared the results. This is a totally informal and unscientific comparison. I'm well aware that there are many variables here I didn't even try to account for. The only question it really answers is, "What can a rank amateur like me with less than five years' experience get from different telescopes on one particular target shot in roughly the same way using similar processing steps?" Frankly, I was astonished at just how close the RedCat and the FSQ came to the CDK.

The CDK's results were much better than the RedCat. And I don't regret getting the CDK. But it gives me great pause when I consider investing well over $100k on a CDK24 parked in Chile. For the same money, I could place copies of all three of the scopes (CDK12, TOA130, and FSQ 106) I have at Deep Sky West down there. And I would likely have fewer issues with those three scopes than the one big one. I don't know how many more trips around the sun I have left. And my personal goals are more artistic and outward facing than they are scientific. So right now, I prefer the wider fields. And I intend my images to be viewed primarily by people who otherwise have no interest in astronomy--not pixel peepers who are going to examine every star at 50X native resolution and feel compelled to tell me how overprocessed my image is.

So while I certainly acknowledge the superiority of a larger aperture, its importance for certain tasks, and its value to some people, my Schwartz is about as big as it's ever going to get.

Timothy Martin:
I'm pretty certain, however, that there is a point of diminishing returns for people on a budget. I spent the first couple of months of the summer framing up the Crescent with all my scopes and compared the results. This is a totally informal and unscientific comparison. I'm well aware that there are many variables here I didn't even try to account for. The only question it really answers is, "What can a rank amateur like me with less than five years' experience get from different telescopes on one particular target shot in roughly the same way using similar processing steps?" Frankly, I was astonished at just how close the RedCat and the FSQ came to the CDK.

I was going to refer to your results and I definitely second your opinion. As a RedCat user, I like to push its limits. I do not think we overestimate the big aperture, but I believe we underestimate what can be done with smaller scopes.