Wedge or Astrotrac?

[Hairycamel]

I have recently aquired a Celestron CPC 925 and am chuffed to bits with it; I even got the permissions officer out of bed to look at Jupiter a couple of weeks ago and she said "Wow, I'm glad you got me up", not "You'll be hearing from my lawyer about this"

Anyway, I digress; I want to start DSO imaging and there are 2 trains of thought that I am torn between. A HD Pro wedge with an ED80 piggybacked and eventually maybe a Hyperstar unit, or an Astrotrac with the ED80 and SLR leaving the CPC for what it's best at - superb visual and planerary imaging.

Another larger EQ mount is out of the question so no HEQ5's or EQ 6's. Another plus for the Astrotrac is it's portability for travelling to dark sites. Any thoughts would be most welcome.

[VigdisVZ]

Not having a wedge for the CPC seems like a missed opportunity to me.

However the portability is a point. Hm... difficult question.

[JamesF]

From what I've read regarding the use of the Hyperstar system for DSO imaging I'd suggest that your use of the expression "I want to start DSO imaging" means it's probably not the sensible way to go.

James

[Hairycamel]

The Hyperstar would be very much in the future when I had cut my teeth on the CPC/Wedge combo, but it would be nice to hear from Astrotrac / wedge users with their comments for the various pros & cons.

[milosz]

IMO Astrotrac is not the best choice for ED80. It may work if you have AT with autoguiding + AT pier + AT wedge but I wouldn't suggest it for the start with DSO imaging. I'm using astrotrac with 135mm photo lens and that is IMO the furthest you can go without guiding. With SLR you probably can get decent frames with 200m focal length, but 600 is way too much.

milosz

[Hairycamel]

Thanks for that, I was looking at the Astrotrac wedge as well to cope with the weight/focal length of the ED80

[ollypenrice]

OK, I hate wedges. I'll just say it. Some people get them to work, many don't, and they are hardly seen at all on the deep sky imaging boards. Given the prodigious number of SCTs out there I think there has to be a reason for this. If you are a mobile imager don't consider a wedge. Your only real hope is with a fixed setup. There will be those who don't agree but I know of literally no serious DS imagers who have stayed with the wedges though some have taken good images with them. They didn't keep them, though...

You could piggyback a small refractor on a wedge SCT. Although I never coaxed a workable DS image out of my LX200 I did get decent images from a piggybacked ZS66.

Trouble is, the alt az fork SCT is a truly lovely setup for DS observing with a convenient EP location (except near Polaris, perhaps) and all that gets shot to bits when you use a wedge.

The Astrtrack is great but keep the FL short if you really want to enjoy it and get consistent pain free results. I'd use a Canon EF200L lens as the max. It's a fine lens though.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=1793797527&k=WMbNhhG

[Hairycamel]

Thanks Olly, I had heard that much longer focal lengths were manageable with the Astrotrac wedge. Any experience of them?

[Hairycamel]

Thanks Olly, I had heard that much longer focal lengths were manageable with the Astrotrac wedge. Any experience of them?

[milosz]

Sure it can be done (), but with full astrotrac setup (mount + pier + wedge + head). I heard Adam also imaged with TS 80mm quadruplet. But with so big focal length you have to know what can go wrong. I tried astrotrac + WO Megrez72 (430mm FL) and I didn't manage to take any good frame. But I don't have wedge and pier.

milosz

[Hairycamel]

Thanks Milosz, it would be much easier if I had the space at home for a spare HEQ5 but hey ho, we live within our limitations!

[milosz]

My HEQ5 lives in a shed in the garden - not a very pleasant place during the winter But it spent last winter on my balcony in Helsinki (-20*C is not unusual there) so I hope it will manage

milosz