Folded Optics, Guide Scopes and mount weight

[Entropy]

Hi guys.

Im thinking about buying an 10" LX200 and was just wondering how do you pick an appropriate guidescope for this scope?
I have a 70mm refracting telescope with a FL of 900mm, but with the LX's focal length of 2600mm, im thinking this will be entirely inappropriate, how can i remedy this, with a Barlow perhaps , or is the 70mm just going to be too small now to put a Barlow in ?

Also, my mount is advertised at being able to carry 26Kg's, does this include the counter-weights ?

Thanks for your help guys
Entropy

[Ian Robinson]

Originally Posted by Entropy

Hi guys.

Im thinking about buying an 10" LX200 and was just wondering how do you pick an appropriate guidescope for this scope?
I have a 70mm refracting telescope with a FL of 900mm, but with the LX's focal length of 2600mm, im thinking this will be entirely inappropriate, how can i remedy this, with a Barlow perhaps , or is the 70mm just going to be too small now to put a Barlow in ?

Also, my mount is advertised at being able to carry 26Kg's, does this include the counter-weights ?

Thanks for your help guys
Entropy

You'd be better of ditching the guidescope and getting an OAG (Meade and Celestron both do these for their SCTs, so do Lumicon).

[Gama]

You can use an OAG, but if its hard getting a guide star to be round or its hard for it to calibrate on, then use a small Mak spotting scope.
You can grab a 90mm Mak with over 1200mm of focal length, which is ample for your guiding needs, plus its small and very light.

As the max weight, i would assume thats total, which includes eveything.


Theo.

[Entropy]

I have been searching for the max weight for my skywatcher EQ6 Pro mount but cant seem to find it anywhere.
Do you think i would be pushing it if i stuck 20-21 odd kilos on top of it ?

And with focal lengths, what sort of focal length will i need to guide correctly ? Will 1200mm be long enough for a main scope at 2600mm ?

[AlexN]

An eq6 pro's payload limit is somewhere around the 26kg mark..

This, however, is the maximum you should put on the mount. If you expect to retain some sort of accuracy in the tracking, staying a bit below this weight would be a good idea... I've seen (and many people on here have) upwards of 24kg OTA's on EQ6's, but they aren't stable enough for photography...

If I were you I'd attempt using the 70mm*900mm refractor you have... Theres no reason to spend money until you exhaust all your options in my opinion... give it a go, if its no good, try barlowing the guide camera... you may find thats all you need.... If its still no good, then consider a different guide scope....

[marki]

The 10" meade tube weighs just short of 13 Kg bare. Most 80mm refractors weigh about 3kg. Add focusers, cameras etc and it could be a close thing. Does the capacity of the EQ6 include the weights to balance? A guide scope is much better then an off axis guider as you can move it around to find a good guide star which is not really possible with the OAG. I use an 80mm apo at F6 as a guidescope with a QHY5 guider (lots of little pixels) and this does a good job even if I leave the LX @F10. Worked when I used the original DSI as well but I mostly use an F6.3 focal reducer to make things a little easier. Your 70mm scope is at about F12 so it should work well as a guide scope with exception of it being longer then the meade tube.

Mark