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Rings or dual saddle?

Guest Steve

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I've got the C9.25 on a CGEM mount and a Williams Optics 66mm Petzval on an AZ4. I'd like to join the two together so I can use the WO66 on the CGEM for potential future photography.

I could just put the WO directly onto the CGEM, but I'm thinking that at some point I will want to do auto-guiding, so to me it makes sense to have the 2 scopes side-by-side so either can act as the guidescope to the other.

I see 2 mounting options:

  1. Put a mounting bar ontop of the C9.25 and mount the WO66 on top using 100mm guidescope rings.
  2. Get a dual saddle so both sit side by side.

Things that concern me are balance and whether I need the ability to move the scopes independently to select guide stars.

Any advice???



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Weight will be an issue - you may need a counter balance bar under the scope (see Modern Astronomy website) and need to watch the mount limit. Not immpossible though. A better bet is to consider a finder guider where the finder scope goes - they're very light and convenient to use (see Altair Mini Guider System). You can pop a Telrad on for doing the finding if you have to replace the regular finder.

Otherwise - if you're going to Kelling there will be plenty of solutions there for rings/bars to mount the Petzval - needs to be dead sturdy though to reduce flexure. :)

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From experience Steve, piggy backing a scope with rings on your sct is easier to balance than side by side. I did that for years with my C11 and WO FLD80 but this puts alot of weight out there which needs to be counterbalanced thus it will make your CGEM s eyes water a bit with a 9.25 and ZS66.

Side by sideing will bring the weight of the scopes in to the mount so wont need so much oppossite counterweighting but the WO is still a heavy scope and the weight of both scopes, side by side hardware, cameras, cables and other imaging paraphanalia which we imagers have to suffer with the all up weight will still be a bit on the tight side for the CGEM.

What Kim suggests may be the better option, then whichever scope you image with you can just slot the finder guider on it and not overload your scope. Alternatively I use an ST80 as a guidescope now, these are very light due to the cheap mmaterials used and this could be an alternative. Although an ST80 guiding a 66 would look interesting :)

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Thanks Kim. Do Traders carry stock of stuff for purchase during the weekend? Do they take cards or is it cash only?

I was hoping to get it sorted before then so I could use the setup during Kelling, but if it is something I can do when there then I will wait - it's always nice to be able to see stuff in the flesh before buying!

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They'll be able to take your money at Kelling - no worries there mate lol. Yes card machines abound and also the old swipe dockets on some stands - they'll have your cash off you too if you let them lol.

They tend to carry plenty of stock and offer show discounts (depending on the size of the retailer). But it's usually the more common items - tailored solutions might need ordering. For what you want - I think you'd be unlucky not to find at least one viable solution at the show. Don't forget a lot of folks also set up stall on their pitches - and there's a "for sale/trade" board too.

Holt is only just down the road 4 miles or so - plenty of banks and cash machines if you get desperate - and the shop on site does cash back as do the pubs and restaurants on site :)

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