Guidance on Guiding

[Stub Mandrel]

This is all at the planning stage... but as it's cloudy:

I'm considering guiding, and for my budget setup the only sensible solution will be a webcam on an auxiliary scope and using PHD. I should be able to set it up to do at least RA guiding with my current setup quite easily.

I'm more worried about the mechanical setup. I have a budget 70x700 scope which, with my HD Lifecam should be OK for the guide camera, but I'm aware this will limit me to stars of about magnitude 6. This means I can't just piggyback the scope and be sure that there will be a suitable star in view, especially as a webcam has a very limited FOV of about a third of a degree.

I know it's OK to have the guide scope a few degrees of axis to find a suitable star, but I can see it being very fiddly to set up.

Are there any simple arrangements out there for mounting a second scope so it can be easily  angled to find a guide star?

[steppenwolf]

The problem with an adjustable system is differential flexure caused by movement of the guide telescope. The firmer the guide telescope is mounted, the better for good guiding. There are adjustable systems but good ones increase the price of the system by at least £120 which is heading towards the cost of a better, more sensitive guide camera!

I wouldn't recommend adjustable tube rings except for a very lightweight guide 'scope like a finder-guider.

[Magnus_e]

This sort of setup will allow you to point the guidescope some degrees.

It's what the Orion Awsome autoguider comes with

[Stub Mandrel]

Interesting. I had imagined some sort of ball joint, but worried about flex. That looks more secure.

I'd already worked out that I could make one of these - it's nice to see they already exist!

http://www.teleskop-express.de/shop/product_info.php/info/p223_Starway-VC4-side-by-side-mount-for-two-telescopes---cameras.html

I wonder if I could split the dovetail clamp into two blocks with a spherical joint? That would be an interesting machining challenge.

P.S. I'd avoid anything with 'Awesome' in the name...

PPS lots of interesting toys/ideas on that TS site.

[Magnus_e]

The side by side mount you link to would probably have less flex than the guide scope rings i linked to.

But you will need some tools to change the angle. The guide scope rings has easy to use thumb screws. If you have set up everything, phd, balance ++ it's nice to be able to use the thumb screws.

Not shure how big of an issue the flex is. Not the limiting factor in my begginers stages

[Stub Mandrel]

Well I've got a lot more ideas now, I'll see what happens!