Quote:
Originally Posted by Lux
I am seeing advertised Newtonians OTAs that are "imaging optimised".
Could someone tell me exactly what has been "optimised" and any subsequent pros (apart from imaging) and cons?
What appeals to me about these scopes is their short length. An f4 200mm scope is only 80 cm long, which makes it extremely portable (IMHO).
Would it be possible to mount one of these on an alt-az mount?
Would anyone recommend a set-up like this as a first scope?
I know I could get a 200mm Dobsonian but these are larger, and as such not as portable. I'm not particularly interested in astrophotography, so an EQ mount is not that high a priority, plus I don't necessarily want the hassle of an EQ as a beginner.
Just trying to weigh things up here - any advice appreciated.
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Hi,
The 8" F4 OTA is ideal for imaging for reasons as others have explained, but can also be used for visual.
Only issue is that you will need eyepieces that work with short focal length or "fast" scopes like the F4.
These fast scopes are almost always used with a coma corrector else you'll get elongated stars both with a camera or an eyepiece.
I have tried some low end eyepieces without a coma corrector on an 8" F4 and stars were elongated.
But I believe the GSO 30mm superview eyepiece works reasonably well with this.
So to answer your question, yes you could use the 8" F4 for visual, but with the right eyepiece and/or coma corrector and a Dob Mount that you could possibly build yourself.
it makes for a rich wide field scope and is portable.
Collimation is a bit more challenging, not impossible.
Have a look at Alex's 8" F4 that he uses with a GSO 30mm SV EP.
http://www.iceinspace.com.au/forum/s...ad.php?t=56400
As for an Alt-Az mount, if you're talking about the ones on tripods, they're usually meant for lighter scopes like refractors or cameras.
I can't recall seeing an 8" OTA on an alt-az mount on a tripod.
For a first scope, I'd suggest looking at an 8" F5 on a Dob mount.
The F5 is about 20cm longer.
The F5 like the skywatchers work well without a coma corrector and work with most standard eyepieces, and are not too large to handle compared to the F6's.
But for planetary viewing, you'd need a Barlow or powermate apart from 6 or 9mm eyepieces, else it'll be very small at short focal ratio's.