Some help with auto guiding please

[pyrasanth]

I want to try some auto guiding on a Celestron Edge HD 11" on a CGEM DX mount. I will practice initially on a few bright planetary nebula.

The question is & having little knowledge of auto guiding is should I look at an off axis guider or a guider that can either fit into the standard 8 x 50 finder (don't know if its 1.25" threaded yet) or replace the finder with another small refractor that can take a suitable guiding device. I would prefer to try simple at first so the guide scope or new small refractor might be an initial way to go. The off axis guider would only be considered if it is compatible with the hyperstar imaging system.

I have a Skyris CCD camera coming with the order & Celestron mention that his can be used as a guider but I have not even explored that option yet!

I have no problems replacing the Celestron guide scope with something if not suitable but I'm bewildered with what scope & guider to use which needs to be compatible with software like PHD which I understand is pretty good. The other issue is if the Celestron offering is replaced how do I fix it to the OTA or are the fittings like drill holes fairly standard.

I will eventually get a hyperstar & again this is why the refractor/finder will be a more suitable solution than an off axis guider as I'm again not even sure if the hyperstar will work with an off axis guider.

Any suggestions to nail this issue would be appreciated. Sorry for so many questions.

[Owmuchonomy]

I'm sure somebody better equipped will answer but my first thought is that the Hyperstar will prevent use of an OAG because you are interrupting the light path at the secondary. As you will end up at F2 with the Hyperstar, guiding may not be completely necessary anyway!

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[knobby]

I'd say from what I've read that with the hyperstar the focal length will be reduced so that a finder guider will probably be sufficient.

Maybe look at something in between like a 60 mm finder .

[Leveye]

Find a used Meade DSI series CCD and a Zhumell 9x50. I found both used for under 150

[Tinker1947]

I use the finder scope with a Lodestar screwed in the end, it replaced the finder focuser.....Modern Astronomy supplied the adapter to fit the Lodestar, in us it gives nice round stars on a 15 minute sub....In Hyperstar mode the FL drops to around 550mm at F2 a OAG won't fit.......

[ChrisLX200]

A small-ish refractor would be good for working at short f/l using hyperstar, but for long f/l (f/10) with an SCT I would advise going with an OAG because it's far more sensitive to guiding errors. With either OAG or guidescope a cheap QHY5-II would be good, or for more money a Lodestar is a popular choice.

ChrisH

[tingting44]

i got one of these bad boys coming, very sturdy, just depends how much you want to spend

http://www.altairastro.com/product.php?productid=16468&cat=108&page=1

[Merlin66]

I use a Lodestar "on-axis guiding" ( reflective slit plate for spectroscopy) - combined with AA5 "slit guiding" or the latest PHD2.2.2c, works 100% with my C11 at f10. No issues, no drama.

[Carina Lass]

I have an off axis guider -

If I had continued using it, I'd be committed by now - went for a cheap 102mm achro F5 SW and I'm just so happy and the look of it impresses people no end!! LOL

My graphs look like the horizon of the atacama desert. Flat with the occassional peak!

I guess what I'm saying is, yes an OAG works, but a separate guide scope is just so much easier.