Orpington Astronomical Society

Astronomy => Telescopes Etcetera.... => Topic started by: Daniel on Feb 05, 2008, 15:00:19

Title: Decision time on a tube!
Post by: Daniel on Feb 05, 2008, 15:00:19
Hi all, just wondering if I could get your advice on which ED80 to buy, the 2 im looking at are both skywatchers, one has better optics and is actually cheaper because it doesn't have as many accessories with it, but does have a shorter focal length, the other isn't quite as good optically (although im told still top notch) but does have the longer focal length, what im wondering is, for astrophotography, and taking into consideration that light polution is a real issue here, which one would you get?

Cheaper, better optics, shorter focal length :-                   http://www.widescreen-centre.co.uk/Products/EQUINOX-80_PRO_OTA_F_500_.html (http://www.widescreen-centre.co.uk/Products/EQUINOX-80_PRO_OTA_F_500_.html)

More expensive, not as good optics, Longer focal length :-     http://www.widescreen-centre.co.uk/Products/EVOSTAR-80ED2_PRO_OTA.html (http://www.widescreen-centre.co.uk/Products/EVOSTAR-80ED2_PRO_OTA.html)
Title: Re: Decision time on a tube!
Post by: Ian on Feb 05, 2008, 15:14:41
I was going to suggest getting the tube that stops closest to your destination...

Generally, I'd go for better optics. But, it still depends on what you're planning on using the scope for. Short focal length with good optics would make a good main imaging scope. Cheaper longer focal length scopes are more likely to make guide scope. Spending more money on a telescope that has inferior optics makes little sense unless you really want the extras it comes with. Bearing in mind, in my experience the extras scopes come with tend to be replaced in short order by better quality items in short order anyway.

What was it you expect of the scope again?
Title: Re: Decision time on a tube!
Post by: Daniel on Feb 05, 2008, 15:19:49
Im primarily looking for a guide scope, but I'd like the ability to image with the scope too especially with all the good thing's i've heard about the ED80 for deep sky imaging. I was under the impression that a longer focal thength is better for light polution is this correct or have i got my wires crossed?
Title: Re: Decision time on a tube!
Post by: Ian on Feb 05, 2008, 15:50:12
light polution's gonna get you whatever you do. However, you can minimise it with filtration.

I'd be more inclined to consider focal length and optical quality first. What you image will be dictated by that to a certain extent.
Title: Re: Decision time on a tube!
Post by: Daniel on Feb 05, 2008, 15:56:32
Cool, have just ordered the Equinox tube with the slightly better optics then ;)
Title: Re: Decision time on a tube!
Post by: JohnP on Feb 05, 2008, 19:22:39
Daniel - I've said it a few times in earlier posts if you were planning on going to Astrofest on either Fri or Sat I would have waited to see if there were any show offers on - often or not you get 10% discounts for orders on the day or even more if you have cash....

John
Title: Re: Decision time on a tube!
Post by: Daniel on Feb 05, 2008, 19:39:19
Unfortunatley with work going the way it is, I think I'll be missing Astrofest, my deadlines have been moved forward and I think I'll be working the weekend! :(