Mounting ST80 Guide Scope

[Gina]

I currently have an Evostar 80 ED DS Pro scope mounted on NEQ6 Pro mount and looking at adding an ST80 with QHY5 for guiding. It looks like the easiest way is to attach a bar to the ED80 scope rings at the top and bolt the ST80 rings to that - piggy-back style. I know another possibility would be to rig up a dual mounting to use the scopes side-by-side.

I would appreciate views on this, please. How well does the piggy-back system work? Any problems with flexing between the two scopes?

[sologuitarist61]

The piggy back system works best I thinks as you do not get the stresses set up by dual mounting - getting the balance right can be a pig, but at least you will have two similar sized telescopes, so the problem would be less.

[Viv]

Mine are exactly as you say.

Bar on top, then rings attached.

No problems with the physical set up at all (other than sourcing all the fitment, bolts & nuts & washers - but got there eventually) .........

[Earl]

I have tried Both ways Gina, I didnt really see any benefit either way other than the height of the guide scope if piggybacked, mine was just under the bar when rolling off the roof by an inch or so, side by side it didnt even come close.

However, I do us the CNC style tube rings on the main ota, this is on a losmandy dovetail, the guide scope is attached via a upside down dovetail and uses adm guide rings with there mini dovetail clamps, I did try attaching basic tube rings together and felt that they were not sturdy enough to stop the whole thing from flexing.

When I had it side by side.. humm I cant remember how I had the guidescope setup, the main was still as above, thr guide must of been atached to a normally dovetail... bit hazy, I think i just attached the guide rings direct to a small divetail without the mini dovetail clamps... ramble ramble...

[Keiran]

I have tried it both ways, and i am currently doing it piggy back. I have found no real difference. I dont think you will notice a flex problem with your setup if you choose to go side by side. your setup is small and light, I would only expect there to be problems with heavier, and larger/ longer scopes.

Only disadvantage with piggy back is the hieght issue. but it is more compact than a side by side.

I think if you mount piggy back, they way you have described is the way to go.

HTH Keiran

[Psychobilly]

I ended up with a piggy backed setup..

My pier is a bit close to a hedge.. when I had a side by side setup I would often end up with one or other of the scopes not seeing the sky...

Now there's only a few inches between the two OTA's...

Peter...

[jgs001]

I've tried both, and ended up using a side by side. Both work equally well. Mainly because I have a couple of different imaging scopes, and it's just a whole lot easier to swap them around in a side by side configuration (especially as one doesn't have any way to piggy back the guide scope, I know I could add to the scope to achieve it, but why bother when I've already got side by side). I've never noticed any issues with flexure, but then my setups tend to be fairly lightweight, short, and as far as I can tell, rigidly mounted.

[Gina]

Thanks everyone I'll go for piggybacking I have a bar that came with either the mount or scope (forget which) and I also have some mild steel angle that I could probably use. I think I'll go for the bar though as it's black anodised aluminium so lighter and easier to work.

[Gina]

I'm using the scope mounting bar. Been drilling suitable holes in it. I'll post a photo when I've done it.

[ncjunk]

Thats what i did as well. I took one of the bars that came with something....possibly a scope...and just attached it straight on top of the ed80 then the st80 on that. Works a treat

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[dark knight]

Mine is also piggy backed and I use a custom "Park" position using EQMod, therefore no height issue of scopes fouling roll off roof.

[Gina]

Done it Having drilled the spare bar, I removed the mounting block from the rings of the ST80 and used the bolts to bolt the rings onto the bar. To attach the bar to the rings of the ED80 I removed the camera attachment bolts from both ED80 and ST80 rings and used these to bolt the bar onto the ED80 scope rings. Because these screws were too long I used the knurled locking wheels as for the camera mounting. I have ordered some Allen headed screws and washers to replace these later.

Here are some photos :-

[gfletcher]

Very similar to my setup Gina

Graham

[Viv]

Gina - just remember you'll need an extension tube for the QHY5.

There is a Skywatcher cheapie barlow on Buy & Sell at the mo (obviously just screw the magnification bit off).

Just in case you didn't know ............ (I hate thinking everything is sorted, then realise I need an additional bit)

[gfletcher]

In the pics of my setup it includes a 60mm extension to enable focus with the QHY5.

Graham

[Gina]

Gina - just remember you'll need an extension tube for the QHY5.

There is a Skywatcher cheapie barlow on Buy & Sell at the mo (obviously just screw the magnification bit off).

Just in case you didn't know ............ (I hate thinking everything is sorted, then realise I need an additional bit)

Thank you for that - I know what you mean Yes, I have a 60mm extension And a 40mm, and a 30mm... I noticed the extension in Graham's photos I had forgotten until then, but would soon have found out once I tried the QHY5

[Gina]

Hmmppffftt!!! Ever since I got the ST80 it's been cloudy at night It's sunny this morning here but cloud and even rain is forecast for tonight!

Seems I should apologise to everyone round here for releasing a great mass of cloud out of the little box the ST80 came in

[icrusoe]

This is exactly the same setup I'm planning on building, along with the QHY5, HEQ5 instead of NEQ6 I believe. How has your setup been holding up to the toils of time?

[kirkster501]

Gina/guys,

Rebooting this useful thread....

So what type of bar did you put on top of the ED80 please? And do the scope rings supplied with the ST80 allow it to connect directly to the said bar? I though the scoep rings would have a bar? Isn't a puck involved here in any way - just like the puck of the mount attached to the bar of the ED80?

I have to unpack every night and would need to remove the ST80 off the ED80. How easy is that to do with this setup?

I can't decide whether to go for ST80 piggybacked like this or to go for a 10x60 finder guider......

Thanks, Steve

[allcart]

I have the same problem Steve in that I must pack away after every session, so I think I have a plan. First I attach a couple of Manfrotto 323 quick release base plates to a dovetail, then attach the dovetail on top of the ED80 tube rings. Then attach the two 323 top plates to the bottom of the SW80 tube rings, I will be able to just unclip the SW80 form the ED80 after the session. Its just the same as if I were removing my dslr from the top of the scope.

Then if I want to use the SW80 as a guidescope, but without the ED80, I just have to change the 323 plates for a dovetail again. Thats about a 2 minute job.

This is only a plan, but I think it should work.

[Rustysplit]

When I was using the st80 on top of my 200p, I had it attached via 2 camera piggyback mount turn buttons. Makes it very quick 'n' easy to disconnect. You can just make them out in the picture. Ignore the angle of the scope, it was just to demonstrate the adjustment of the diy mount.

[Tinker1947]

Here's my set-up, mounts straight onto 2 studs on the 10" rings and can if need be mounted straight to the mount dove tail, spacers and 1.25" adapter are help firmly in place with self amalgamating tape (minimum focus tube extended about 5mm), the Lodestar (waiting replacement) held in place by with its C-Mount threaded Adapter so there's no pressure on the CCD.....http://www.firstligh...-c-threads.html

[allcart]

too simple. ........Don't know why I didn't think of it. I will counter bore the bottom of the dovetail to make the bolts flush though.

[Tinker1947]

The 2 studs with nuts at the bottom are i believe Whitworth threads, the 2 bolts either end of the same block that attach to the tube rings are Metric,,,,,all supplied in the same package....what i was short of the Whitworth so had to cut down some long shank bolts just to use the thread bit,,,,really needs tiding up, there is quiet a bit of space between the dovetail bar and the tube...one other thing, the plastic base requires trimmimg so its a snug fit in between the top of the dovetail rails...i run it through a table saw to get it even both sides....

[allcart]

I noticed the plastic base was wider than the dovetail. It looks like yours is just sitting on top.

One thing that still puzzles me though, is how to move the ST80 in order to centre a star in my Synscan when I get it. I'm assuming of course that the guidescope will be perfectly aligned with the main scope and will see exactly the same stars. It has been said that sometimes you have to move the guidescope a bit to centre a guidestar.