Mounting ZS66 on ST150 for Guiding.

[quantumpanda]

I'm going to be very non technical here, because I am unfamiliar with SCT threads.

The outer diameter of the 2" nosepiece, is the same as the focuser.

The 2" nosepiece screws into a much larger female thread.

I put the 2" nosepiece male end against the Flattener, and it closely matches the diameter of the inner female thread, but it's slightly bigger. Thus, the focuser, which has the thread on the outside, is slightly too big.

Hmmm.

[Komet]

The lens body of the focuser is designed to attach to the drawtube of the focuser .....

Specsw here .... William Optics - Flattener III

Note the SCT thread bit .... that is the thread on the end nosepiece and where the nosepiece screws into the lens body.

If you remove the 1.25" adaptor on the scope it leaves the focuser drawtube with a thread on the end. That thread is the same as that in the lens body of the flattener (SCT). You screw the lens body of the flattener onto the drawtube direct.

If the threads are different then you have something non standard somewhere.Perhaps you could contact WO to see what they say.

[quantumpanda]

I understand what you're saying Komet, but there is a slight discrepancy. I will email William Optics though, as I believe the focuser is the one that came with it.

[Glider]

My FF II works as Komet says, all be it with my previous reservation about possibly needing a spacer between it and the focuser tube. I guess this would have to be an SCT male (into FF cell)/SCT female (onto focuser tube) spacer.

The WO link, where I got my earlier screen shot from, certainly implies you have an SCT female thread once you have removed the nose piece from the FF III. This should go onto the focuser tube SCT male thread????!!!!!