scope for autoguiding

[piprees]

Hi, after reading about various scopes used for attaching an autoguiding camera, anything from a skywatcher ED80 down to a 9x50 finderscope, how about a relatively cheap beginners scope like a Celestron Travel Telescope 50. Obviously this scope doesn't have the finesse of the ED80, yet surely is comparable to a finderscope. Any comments gratefully received.

Kind regards,

P.

[AstroAdam]

As long as you can reach focus after attaching a guide cam, then in theory anything can be used a a guide scope.  The real limitation is the focal length of the scope that's being guided.  If you;re trying to guide a very long f/l scope with a small scope (be it one of these, or a finder guider), then you'll find the guiding is less accurate the bigger the difference between the focal length of the guidescope and the main scope.

I've used a finder guider to guide up to a 1200mm focal length f/6 newtonian.  This should do the job just fine if you're not going to try and guide an unreduced c8 or something!  Bear in mind you also have to rigidly attach the guide scope to the main scope too, with as little potential for flex as possible.  

[AstroAdam]

Also, a smaller scope has a wider field of view, so more potential guide stars in view.  Also have to bear in mind that a longer scope (like an ST80) will a smaller FOV, but the stars will be brighter. Swings and roundabouts!

[Leveye]

Zhumell makes a 9x50 finder for $69.99. It's the same as the Orion at $89.99 and most likely made by Zhumell. Highly recommended.

[piprees]

Thanks Adam, it'll be for a skywatcher 200p so, hmmmm, have to give it some thought.

[cthorpey]

I use a Travel Scope 70 with a ASI130 camera. Never had a problem finding a star to guide with.

I have had loads of problems getting my graphs flat but thats another story!!

[piprees]

Thanks cthorpey, I've been considering the skywatcher syguider. Reviews have been a little ambiguous. They do away with using a laptop but not too sure about actually locking onto a star. Has anybody had practical experience of one of these? P. 

[ollypenrice]

For me a fast F ratio is the key thing. I find the ST80 an ideal guidescope. It's cheap, light, fast and has the kind of focal length that is fine until you want to guide longer FL reflectors which are best with an OAG anyway. (It may be argued that F ratio is not important for point sources but in small amateur scopes stars are not point sources.)

The standalone guiders get a mixed press because they work when they work. When they don't work (and guiding is something that works or doesn't work largely as it sees fit!) they are not easy to trouble shoot. I would always advise the flexibility of a separate guide camera and the wide choice of guiding software that is available. If you don't get on with one, try another. And PCs have big screens. Poking around on small ones is always a nightmare.

Olly

[Liquid360]

This is more of a side-note than anything, but for those who might be close to purchasing a new CCD, guiding tech is built into the newer cameras negating any need for a guiding scope. The camera has a built in OAG in front of the main sensor. This is news for some, not for others. I ended up with a completely unnecessary 90mm Stellarvue for lack of knowledge. This is why I bother bring it up.

[ollypenrice]

This is more of a side-note than anything, but for those who might be close to purchasing a new CCD, guiding tech is built into the newer cameras negating any need for a guiding scope. The camera has a built in OAG in front of the main sensor. This is news for some, not for others. I ended up with a completely unnecessary 90mm Stellarvue for lack of knowledge. This is why I bother bring it up.

It needs to be in front of the filterwheel as well, and often is. You won't be guiding well through a 3Nm Ha filter!!

Olly

[Liquid360]

Ah well.... good thing I've got an extra SV90 and 5nm filters sitting around. [emoji6]

[glowingturnip]

i use a T70 travel scope to guide a 750mm newt.  Does the job just fine, and they come up cheap on Ebay.  Need to figure our some way of attaching it firmly though

[Liquid360]

Stellarvue recently released a very reasonably priced guidescope in typical stellarvue fashion, well made and priced.

http://www.stellarvue.com/stellarvue-50-mm-photographic-guide-scope/