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Peter R,
I think a guide scope is somewhat wishful thinking at almost any focal length. PME will not guide without an autoguider and get round stars at regular and long focal lengths. I doubt ME 11 is any different in this regards. Claims Protrack can do long unguided round star images I think are highly spurious. I have a 310 point T-point model and I find Protrack enabled does improve star roundness but not 10 minutes unguided at 2 metres +.
I am currently using a guide scope on my CDK17 and reducer setup because the Planewave reducer whilst a nice unit optically has almost no backfocus and CCD has to be 45mm from the back of it. That does not really allow an OAG. I am considering SX filter wheel with built in OAG or TS OAG 9mm thick as alternatives or even using an AP reducer in place of the Planewave one. Setups often require ongoing tweaking.
I am using a little Vixen 95 VMC scope that is remarkably good for its cost. I get quite round stars with a decent PEC curve (oops shouldn've brought that up eh!!) and Protrack assisted guiding. 10 minute subs are often very round stars and sometimes a tad elongated. That is fairly tweaked and very rigid so must be close to as good as it gets.
So when planning out whatever system you intend I would put either a OAG in the system or consider the self guiding SBIG systems. Starlight Express have OAGs that fit with their cameras. QSI WSG cameras are also good for that. Not sure if they sell a 16803 yet or are about to.
Flexure as Mike can tell you is the enemy of fast systems. So heavy camera/filter wheel combos are somewhat inappropriate. A FLI Microline 16803 is currently the smallest/lightest of the 16803 cameras. But no guiding solution so you have to add in a MMOAG or other OAG to the system.
The Planewave focuser is very very good so that is not a worry. Its built like a tank and the electronic focusing is very accurate and does not slip (its geared). I also think Planewave now have gone through the beta stage (they did not have many bugs to start with, mostly baffle issues and stray light) and is now quite a mature system.
Greg.
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