What size guide rings??

[brantuk]

Just a quick question. I need some guide rings for my ST80 and wondered what size (diameter) you have had most success with? (bearing in mind fit, ease of use, and weight capacity).

Thanks in anticipation

[ollypenrice]

Do you mean adjustable ones as used on finderscopes?

I don't use them for three reasons. 1) Not necessary since a decent guide camera will always find a star. In the unlikely event of being unlucky ( hasn't happened to me yet) if you use a single bolt to hold down the guidescope you can pivot right or left to search for one. 2) They are flexure prone, espeially on something like an ST80 with short main tube, so not much distance between the rings. 3) They cost a fortune!

Quite a few members find the same, no need for guide rings. A bolted down system is always stiffer. Just check the crossheads that hold in the rear assembly of the ST80 to the tube and always lock up the focus lock quite hard to avoid flexure.

In order to have a quick release guiidscope I like these things from Baader. In effect mini saddle plates, they clamp a length of Vixen/Synta dovetail onto which the guidscope is bolted. This also allows you to fine tune dec balance by sliding the guidescope fore and aft. http://www.baader-planetarium.de/sektion/s03/s03.htm

Olly

[brantuk]

Many thanks Olly - I'm actually working on a solution for a more permanent and heavier scope (Meg72) involving ADM bars and one of these:

First Light Optics - Skywatcher Guidescope Mount

At the moment though I need a quick temp solution for some test runs using an ST80 with a mod'ed webcam for guiding. So I really just need to know what diameter to choose and wether it will be adequate to carry the ST80 (in the short term).

[RobH]

Hello Kim.

I totally agree with Olly......guidescope rings are a waste of time and a cause of all sorts of problems for the reasons he says.

I don't use them either.

Rob

[mag10]

Do you mean adjustable ones as used on finderscopes?

I don't use them for three reasons. 1) Not necessary since a decent guide camera will always find a star. In the unlikely event of being unlucky ( hasn't happened to me yet) if you use a single bolt to hold down the guidescope you can pivot right or left to search for one. 2) They are flexure prone, espeially on something like an ST80 with short main tube, so not much distance between the rings. 3) They cost a fortune!

Quite a few members find the same, no need for guide rings. A bolted down system is always stiffer. Just check the crossheads that hold in the rear assembly of the ST80 to the tube and always lock up the focus lock quite hard to avoid flexure.

In order to have a quick release guiidscope I like these things from Baader. In effect mini saddle plates, they clamp a length of Vixen/Synta dovetail onto which the guidscope is bolted. This also allows you to fine tune dec balance by sliding the guidescope fore and aft. Schwalbenschwanzsystem Vixen, Celestron Typ V bei Baader Planetarium, Zubehoer - Sektion 03

Olly

Gee, I wish I'd known that.

I bought these thinking I would use them for a SW 102mm as guidescope. (I liked it so much by itself, that I just got this Orion 80mm as guidescope instead).

They're 6".

I haven't used the setup to guide yet, so I can't say how it performs.

I thought I'd show you what it looks like, since you also have an 80mm short tube.

Maybe it will help you in your decision.

[Spikey]

I'm just about to start guided imaging so my experience, if it's of any use to you;

I'm using a standard skywatcher 90mm set of rings on the ST80.

These are then fixed onto the dovetail and attached to a dual mount side by side ADM set. Not used the set up in anger yet but my tests so far have been good.

No shortage of guide stars and no need to move the ST80 at all. I'm using PHD through a QHY5 guide cam.

Intersting use of only one of the scope rings, might have to try that as my local B&Q don't seem to ever have the right bolts/nuts.

[brantuk]

Thanks Spikey - yes I've just taken a dual bar arrangement to pieces - it was really quite good using just the standard 90mm rings.

However the setup I'm putting together is with a piggy back guide scope because the main scope is too large for the dual bar. So I want a little bit of adjustability

[JoLo]

I have had good luck with guide rings from ADM. I use them on an AT65 piggybacked to a 4" refractor. Now, they took some getting used to mind you, especially when locating a guide star, but a little practice and I know which bolts to loosen and which to tighten to get the star centered. I have also had success with the camera attached to the 65, using the big scope to guide.

I did upgrade my Atlas saddle to accept Losmandy plates, i am sure that helped...also, do need to make sure the bolts are tight, or slippage can be an issue, but a little practice and they work like a champ...for me.

Joe

[Mr Spock]

I had a 80mm attached to my last scope with a pair of ADM 125mm rings. Worked perfectly once adjusted.

[brantuk]

Thanks Jolo - this is only a temporary measure to fit an existing ST80 for a few test shots with the larger scope - in a few weeks it will all be replaced with an ADM set up and an alt/az adjustable shoe bearing a different (larger) guide scope.

Meantime I just wanted to know what size guide rings to use with the ST80 as a cheap and quick measure.

[brantuk]

Affirmative Mr Spock! lol - thanks v.much - 125mm (5") it is

[kk4df]

Affirmative Mr Spock! lol - thanks v.much - 125mm (5") it is

I use the ADM 125mm rings as well for my ST80 guidescope. Good luck!

[brantuk]

Thanks Walt

[mindburner]

I'm just about to start guided imaging so my experience, if it's of any use to you;

I'm using a standard skywatcher 90mm set of rings on the ST80.

These are then fixed onto the dovetail and attached to a dual mount side by side ADM set. Not used the set up in anger yet but my tests so far have been good.

No shortage of guide stars and no need to move the ST80 at all. I'm using PHD through a QHY5 guide cam.

Hi I wondered how you got on with the ST80 and the 90mm rings. I happen to have a set of those rings and I have just ordered a ST80 OTA. Not sure whether to mount ut on top of my Meade 127 APO or side by side as the side by side bar has not mounting plate on it so would have to buy/make one or drill some holes. I plan a QHY5 and PHD also

cheers

[Spikey]

Hi, I got on really well with the rings side by side - I can get 30min + subs now. Which aren't much use where I live with a DSLR but should be good for star parties and eventually narrowband CCD. I have upgraded them now as I purchased an adjustable set at a bargain price. I kept the originals as spares. The QHY5/PHD is a good, tried & tested combo. I'm also using the Atik 16iC as a guide camera at the moment while I image with the DSLR.

[mindburner]

Many thanks Spikey. I hope to start on a few minute exposures and see how it goes. I got a loarge RA plate with the scope. I mounted the SW rings on a small dovetail then drilled a few holes in the plate and mounted the dovetail to it. Seems pretty firm. I does not have much adjustment, but hopefully the ST80 will be sensitive enough to not need moving to find a suitable guide star