WO Star 71 Mounting Advice

[gnomus]

I have just received my WO Star 71. It is a very compact scope.

I have two options for guiding - the ST80 that I am using now, or the ED80 that the WO is replacing. Either guide scope will be larger than the WO71. The ED80 would make the rig look quite top heavy and it may interfere with the camera and/or filterwheel. I would like to use the ED80 for guiding because this could then do double duty as my solar scope.

As such, I am wondering if I should mount the WO71 on top of the guiding scope. Would there be any compelling reason not to do this?

Regards.

[steppenwolf]

Congratulations on the receipt of your new telescope!

As a general preference, you want the imaging 'scope as closely coupled to the mount as possible - the lightweight ST 80 would make more sense for piggy-backing on top of the WO Star 71 but I hear you regarding the ED80 for dual use.

Out of curiosity, why have you discounted using your ADM dual bar mounting?

[Uranium235]

Dual saddle would probably be the best way to go, it puts less stress on the tube rings (and therefore reduces flex). But an 80ED or ST80 would be a bit of overkill for guiding a Star71, probably better off using a finderguider.

There is a good chance you will need to flip the Star71 upside down as well because if you install a longer dovetail bar (to aid balance) it may interfere with the focuser. I'll post my configuration a bit later on.

[Thalestris24]

Hi

Wouldn't a lightweight finder-guider or similar do? Here's my SW 9x50 finder attached to the 480mm TS APO - it's nice and rigid and works fine

Louise

[gnomus]

Congratulations on the receipt of your new telescope!

As a general preference, you want the imaging 'scope as closely coupled to the mount as possible - the lightweight ST 80 would make more sense for piggy-backing on top of the WO Star 71 but I hear you regarding the ED80 for dual use.

Out of curiosity, why have you discounted using your ADM dual bar mounting?

Thanks for the advice so far. I do have a dual mounting bar, but one side has a C8 Edge clamped firmly into it. I've only just got the dual bar and find it a little bit of a challenge to get it all balanced. I was hoping I could get it all set up and then not have any further tinkering.

Nevertheless, the consensus seems to be that the WO should be on the mounting plate. I don't have a finder guider for the WO and I must say I do find the ST80 works quite well.

I would be very interested to hear what all the options might be.

[Spikey]

Will all 3 scopes sit on the bar side by side?

[gnomus]

Will all 3 scopes sit on the bar side by side?

Not sure I understand - the bar has only two saddles.

[Spikey]

Not sure I understand - the bar has only two saddles.

Hi Gnomus, you will need another saddle to get three scopes on, but if they will fit and balance you have another option.

[gnomus]

Hi Gnomus, you will need another saddle to get three scopes on, but if they will fit and balance you have another option.

Understood. Things already complicated enough. For the moment I've gone ED80 in one and WO71 in the other. The solution for the C8 struck me this afternoon. Simply build a second observatory.

[Spikey]

Understood. Things already complicated enough. For the moment I've gone ED80 in one and WO71 in the other. The solution for the C8 struck me this afternoon. Simply build a second observatory.

I like your thinking !

[steppenwolf]

The solution for the C8 struck me this afternoon. Simply build a second observatory.

Of course! An enlightened solution, Steve ...........

[Davey-T]

I have my WO 110FLT and WO Star 71 on dual mounting bar, guiding by swapping between the two ATM but hoping to mount guidescope between them, still waiting for FLO mount to materialise, may have to buy ADM one soon 

Dave

[gnomus]

I have my WO 110FLT and WO Star 71 on dual mounting bar, guiding by swapping between the two ATM but hoping to mount guidescope between them, still waiting for FLO mount to materialise, may have to buy ADM one soon 

Dave

Why not use an OAG with your two refractors? (I am toying with doing something like that if I get a 115 or something similar.)

[Uranium235]

If youre sticking with the C8 on the other side, then all the more reason to try a finderguider - in theory, it should be able to guide both. Here is how mine is set up:

9x50 finderguider, mounted via mini guidescope rings and a vixen saddle (ironically swiped from my dual saddle bar!) attached to the upturned Star71 dovetail bar:

M48 male > EOS bayonet > M48 female > FW > Atik 383L+  (bayonet allows me to quickchange between cameras, however it required a ~0.4mm thick plastic spacer to take the slop out of the TS adaptor (simply cut it out of a cheap ice cream container top). As you can see, not much focuser travel left, but ive found it to be enough to focus all the filters I have:

The whole thang... including Dew strip, spare saddle used as a stopper, and an extra long dovetail. Pardon the wooden mount for the RDF, thats just temporary until I can build something a bit more suitable:

[Thalestris24]

Just to say - nice monochrome pics, Rob!

Louise

[Davey-T]

Why not use an OAG with your two refractors? (I am toying with doing something like that if I get a 115 or something similar.)

Got OAG on the SCT and not that fond of it, could have got the QSI683 with one built in but decided against it, once I get separate guidescope working then I can have the 110 and 71 imaging simultaneously 

Dave