Guidescope question

[Geoff45]

Can anyone recommend a good source of guidescope, rings etc for a 4" f/7 refractor?

[[1ponders]]

Depends on if you want the best (http://www.losmandy.com/secondary.html)or not :) You can buy them direct from Losmandy or from Optcorp (http://www.optcorp.com/product.aspx?pid=2511&kw=Losmandy&st=2)(who also carry Williams Optics gear). Btw you will want at least the 125mm rings to fit your scope (I have a 4" I use to guide sometimes) but the 160's (http://www.optcorp.com/product.aspx?pid=2508&kw=Losmandy&st=2) would be better. The 108's definately won't fit.

[Geoff45]

Actually, I was thinking of a guidescope for the 4" (WO ZS110 on order), but yes, the Losmandy stuff looks good. I could use the 90mm with a 70 mm guidescope.

[Striker]

Geoff doesn't the ZS110 come with rings..if so I would be just putting a losmandy dovetail plate on top with some 90mm or 125mm losmandy guide rings.

[JohnG]

Hi Geoff

I don't know if this will help you or not, attached is a couple of photos of my 4" Tak mounted on a G-11 with an 80mm SW Pro Series as the guidescope.

All mounted on a 12" Casady tandem bar, 12" saddle and H/D BT Technologies dovetail for the Tak, Casady TGAD, Losmandy DUP, Parallax rings and 8" saddle for the 80mm.

An excellent and very stable imaging system. :thumbsup:

Cheers

JohnG

PS: The SW ED80 is set like that to get at the finderscope. :P

[gbeal]

John,
nice setup, very nice. How do you align the guidescope? Presumably they are pointed at the same object. I find that with the Losmandy DR125 rings that I can play" around a bit and find a guidestar that is bright enough.
A shame both finders sit to the left.
Gary

[JohnG]

Hi Gary

I originally used guidescope rings but changed to the Casady Tandem Guidescope Aiming Device (TGAD) look here:

http://www.robincasady.com/Astro/TGAD.html

To get the finderscope on the ED80 so I could get at it, I rotated the tube 90 degrees, the finder is now on the right, I need it there to get at guidestars using the TGAD, also my crosshairs are aligned so when I centre the guidescope, the target sits in the centre of the ST-4 guider chip.

Cheers

JohnG

[Merlin66]

You many want to think about an old ETX 90 as a guide scope; they're pretty cheap don't weigh much ( mine is 720gms with rings) and are very compact. Oh they also include a free flip mirror!!!!

[Geoff45]

Yes, Thats what I was thinking of doing after reading Pau's suggestion.

[Geoff45]

Where can I get one?

[[1ponders]]

Sweet looking TGAD. I like alot :love: I know what I'm going to be asking for in my xmas hamper :D Along with everything else of course.

[Merlin66]

There's a couple on Astromart for around $220 ( Look for the older RA model, no GOTO etc , the optics are the same)

[Striker]

Merlin how do you find guiding with Mak/Cass...from what I have read it's not that optimal as your adding movement of the Mak primary to the equation.....something that is bad enough to do deal with if your imaging with a SCT then to add this to guiding......I suppose thats why the cheap Acho or even the ED80's are a popular guide scope option.

I would be interested in your thoughts on this Merlin because I once looked at a Mak/Cass for guiding but was put off by all the feedback I have received.

[Merlin66]

Doesn't appear to be a real issue at the moment; wait till I get more "serious". The only comment Ive seen on MAPUG is re the flip mirror positioning. Very compact and, as I said appears to do the job well.
Keep you posted.