apo for imaging

[mikeglr]

hi all could do with some advice i'd like to buy a refractor for imaging i've got £700.00 to spend could probably push to £800.00, i've been looking at the orion eon 88 ed apo which is £699.00 as i'm still learning the art of imaging {going by the review's} it seem's like a good buy or would i be better saving more and getting 120

i've never owned a refractor before so any help would be appreciated

cheers

[Ben Ritchie]

What camera/CCD are you using with it?

The thing to remember with imaging is that aperture isn't everything, you're primarily concerned with focal length and f/number (which, of course, are related to aperture). To take a simplified view, the former sets the image scale, the latter exposure time and - in the case of refractors - the colour correction. So 'fast' (i.e. low f/number) is good, BUT a general rule of thumb is "fast, cheap, well-corrected - pick any two'. Fast, well corrected refractors are expensive, especially as apertures increase.

So for an imaging refractor i'd be primarily concerned with optical quality, colour correction and having a good solid focuser - plus you'll probably need a field flattener if it's a DSLR or big-chip CCD. So i'd go for a good-quality 80mm triplet, rather than going for larger apertures.

[Catanonia]

If you can stretch a bit, the SkyWatcher Evostar Pro ED120 Diamond Black is very very nice.

Sky-Watcher Evostar 120ED DS-PRO telescope.

120mm F7.7 @ 900mm but about £990

Very nice or try one of the smaller ones

Sky-Watcher Evostar 100ED DS-PRO telescope. is £629 but F9

You might find it cheaper at other shops.

[MartinB]

I agree with Ben, stick with a fairly short focal length whilst you are getting to grips with things. You will have a wider field of view and the lower magnification makes for a much more forgiving set up when it comes to tracking and focusing.

A Skywatcher ED80 would be an excellent choice, well within budget and a superb performer. You will really be able to cut your teeth with a scope like this and, if you ever want to move on you will have no problems selling it.

[mikeglr]

thank's for the info guy's time to go shopping

[Rossco72]

The Meade 5000 80mm triplet may also be worthy of consideration at around £550ish. But you will hear nothing but good things about the Skywatcher Equinox scopes (At least I have yet to find anyone who isn't happy with theirs)

[Aza]

Personally I would love a Borg refractor.

Lots of options and upgradability when you get your head around the configurations.