AT-72ED II piggyback on Celestron C8 SCT

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Garrett D'Amore avatar
I am running a C8 XLT on a CGEM-II mount.  It seems to be pretty solid (and damn heavy!), but now I'm getting good images.  This was my first AP rig. (It probably shouldn't have been, but hindsight and all that…)

So now I'm looking for something that give me shots of larger objects, M31, nebulae, etc.  And I'd like to avoid buying an entire new kit.

So what I'm thinking is that maybe I can piggyback something like the AT 72EDII on the C8.  I'm thinking my mount can handle the weight.

Has anyone else done this?  How has it worked out?  And if I go that route, what is the best way to fix the refactor to the SCT?  I'm guessing I could buy a full length CGE rail to put on the top of the SCT, but it seems like that adds a bit of weight, and will require me to use some kind of adapter to convert that rail to a saddle for the refactor.  Which adds still more weight, and more expense.

The main thing here is that I leave my setup mostly outside covered, so that it's easy to get started by just taking the cover (a soft Orion cover) off.  I'm trying to leave me with a setup that I'll use, and not need to tear down every time I want to switch scopes.

(I suppose that might be foolish, since there are other parts of the train to move .. .EAF, EFW, OAG/guider, etc.  Should I just accept that I'm going to be moving stuff around when I change scopes?  At least until I have enough set aside to buy a complete separate rig (mount, focuser, etc.)?
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John Richards avatar
I have a setup with a 4 in refractor on a GEM45.  I wanted to be able to switch the piggybacked 50mm guide scope with a Lunt 50tha and perhaps also with my AT72EDII.   So I purchased one of these https://www.highpointscientific.com/adm-accessories-v-series-dovetail-saddle-plate-tapped-version-vsad-tpd from Highpoint Scientific along with a Losmandy D plate which I mounted to the top of the refractor rings.  I then mounted the dovetail saddle plate to the Losmandy D plate.  This allows me to easily switch out the guidescope, for the Lunt or the AT72ED II.  Of course, everything has to be rebalanced on the mount when a change is made.  So far, though, I have everything in place, the only thing I have actually tried is the guide scope, as we have had several weeks of clouds, but that should allow a relatively fast change on top of the larger refractor.  The setup is solid and I was able to achieve good guiding (.5" - .8") with the guides cope mounted this way.

Hope that helps,

John
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