Quote:
Originally Posted by ausastronomer
Hi Peter,
As a visual instrument there is not one single performance criteria where a SCT telescope can outperform a newtonian and in many performance criteria as a visual instrument they are clearly inferior.
There are many reasons why people want to own and use a SCT for visual astronomy and they are vaild for each individual and their circumstances, but optical capability isn't one of them.
If you want I am happy to spell each and every one of them out for you. Its pretty simple optics and physics. The optical and physical theory is backed up by what I have experienced at the eyepiece comparing the two scopes countless times over several decades.
As an imaging telescope it's a whole different ballgame.
Cheers,
John B
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I get consistently better results on planetary on my C8 than other people with my experience level get on their 8" newts. The best amateur planetary photography I see online is done on C14's and SCTs. I also am not a fan of diffraction spikes. I find the SCTs much easier to handle and setup and use, and I much prefer the eyepiece position for most viewing.
I can add a hyper star and image at F2 for not a huge investment, and have a really compact scope that can do planetary and ultra fast DSOs and not be out all night getting enough subs.
An 8" newt is nearly twice as long as my C8, and nearly 3kg heavier than my C8. A 10" newt is what, about 1.2m long and about 16kg vs 60cm and 13kg for a C11. I find an SCT far more usable to mount and move around, especially with cameras attached. So for a Newt and an SCT of the same physical size, the SCT will kill the newt optically, as I can have an 11" SCT for the same length as a 6" newtonian.
There are a ton of reasons why a newt is 'better' than an SCT, there are plenty of reasons why a refractor is better than a newtonian, and an RC better than... and so on. There are reasons an Android phone is better than an iPhone and vice versa.
The best scope is the one you use as they say, I personally found I didn't use the 10" newtonian I had in the late 80s, I sold it and bought a C8 on a simple fork and used the hell out of it, as I could just grab it by the forks and chuck it in the passenger seat. I used to take it camping, it went everywhere with me, and it took lots of photos on hypered film through my poor old olympus SLR.
For critical viewing there is always a better telescope than the one you own, anyone can argue up and down all day why the one they prefer is the best, and just about everyone can prove they are right
That's why I said "I'm not a fan", and put a 'wink' after it, rather than saying "SCT is better".
It is simply stating that I don't personally like them, not that SCTs are necessarily a better scientific instrument, just that I get more enjoyment (and therefore better results) using one. They are a popular scope and suit a lot of people. So are refractors, so are newtonians and dobs, RCs and Maks, we are spoiled for choice these days, which is a great thing.
I've become a huge fan of refractors in the last month or so, but again, a 4" one is my personal sweetspot until the day I can afford to buy my own house and setup a permanent observatory.