New to Autoguiding...

[Timothyterpsalot]

Hello all, I'm new here. I'm wanting to start doing some autoguiding and don't know where to start. I will be using an Orion 8" f/4 800mm scope on a CG-5 mount. I don't know whether off-axis guiding or not would be the better option. I like the idea of not having another scope on the mount. Is off-axis guiding on a newtonian pretty much the same as on a SCT?

I've never done any autoguding before and have read a lot online about it but I guess I'm looking for your input on this.

[michaelmorris]

Here is an excellent audio with slides presentation on autoguiding that you may find useful.

http://www.stark-labs.com/movies/NEAIC08_Guiding.html

[Timothyterpsalot]

I guess my question more relates to off-axis guiding or having a separate scope. Does one have advantages on Newtonians over the other? For example, does off-axis guiding on a Newtonian have problems with the focuser not being steady enough with a DSLR and a guide camera?

Is there anything else I should know? I'm leanin towards off-axis guiding. That is why I'm asking. Thanks!

[ncjunk]

Your main worry will be if your newtonian has enough back focus, movement in the focuser, to achieve focus.

Depends on the scope, oag and camera combo that you have and you need to measure the focus point with just the camera and see how much movement you have left.

I am not very good on that but someone will be able to give you a run down.

I have an OAG on an Ed80 scope and i like it a lot, very easy.

[SteveP]

Tim

As Nick says, the difficult issue with using an OAG on a Newt is the limited backfocus inherent in a Newt's design. I'm guessing that's why most Newt users have installed a separate guide scope. To see whether you have enough BF, work out where the focal point is and imagine that this is where the plane of the CCD in your camera has to be. If that point is sufficiently beyond the focus tube when it is retracted to install the OAG and whatever adapters you will need to connect the camera>OAG>focus tube then you'll be OK. If not, then it will have to be the guidescope route.

HTH

Steve

[Merlin66]

Lumicon do an excellent Newt OAG, low profile body - works very well.

OAG is prefered if you intend doing long prime focus exposures.