Guidescope mounting

[DavidH]

Hi Everyone,

I am looking for some advice on mounting an ED80 guidescope on my Meade 8" SCT on a Losmandy GM8. Should I try to mount it piggyback or side by side?
What are the pros and cons of both approaches? I want to be able to use either the SCT or the ED80 as the guidescope.

Regards and thanks
David.

[JohnG (John)]

Hi David

Both approaches will work BUT if you are using the standard GM-8 tripod, I would suggest you mount it piggyback. If it is mounted on a permanent pier, side by side will work. If you are using a G-11 tripod, go side by side.

ADM make a good mini piggyback system, Losmandy make a better system using a "D" series plate and rings, ADM are reasonable in price, Losmandy are expensive but you get a better quality.

The scope setup you mention would be the absolute maximum for that mount as by the time you add a camera, possible autoguider and other bits and pieces, you are getting near the load limit. Piggyback you will need to balance correctly in 2 axis, side by side, you need to balance in 3 axis.

With the piggyback setup, you may need a bit more weight than the standard 7lb, I used 11lb with a C-8 and similar guidescope. Remember the recommended weight should not exceed 2/3rds the capacity of the mount.

I use a GM-8 in a similar configuation.

Photos are in the Equipment link below.

Cheers

JohnG

[DavidH]

Thanks John,

I thought that mounting the guidescope would bring the mount to its limit, but want to give it a go anyway. The SCT alone needs a tad more than the current 7lb counterweight. I may at some time in the future mount it on a pier, but at the moment all I have is the GM8 tripod. Maybe my best option for imaging would be to use the ED80 as I currently have it set up with an old Tasco 50mm refractor as a guidescope. This seems to be OK, although I have not had much of a chance to use it for the last 3 months due to work and cloud .

Regards,
David.