Attaching The ZWO CAA To A Sky-Watcher Evostar Telescope

If you’re like me, then you’ve been a bit keen on the release of the new ZWO Camera Angle Adjuster (CAA). So I was very happy when mine came through the post. Though that happiness very quickly became confusion as attaching the ZWO CAA to a Sky-Watcher Evostar Telescope proved a little fiddly. In this article, I’m going to show you how I went about attaching these ready for a clear night.

So it took a bit of measuring and a few ordered parts, however I’ve managed to now get mine all attached and working. So in this quick article, let me take you step by step on how I did it.


Attaching The ZWO CAA To A Sky-Watcher Evostar Telescope

This applies specifically to my Sky-Watcher Evostar 80ED telescope with its matching 0.85x dedicated Reducer/Flattener. However I can imagine all Evostar telescopes have a similar focus tube, and perhaps even more Sky-Watcher telescopes will include this same thread size.

The Problem

The issue lies in a mis-match of thread diameters on both the ZWO CAA and the Sky-Watcher Evostar focus tube.

On the ZWO Camera Angle Adjuster, the threads are machined to a M54 diameter. So, 54mm in diameter.

The focus tube on the Sky-Watcher Evostar 80ED however has a diameter of 56mm, so it’s an M56 x 0.75 thread. The 0.75 thread pitch isn’t a problem here. It’s the diameter.

This isn’t usually a problem. The focus tube has M56 threads, and the matched reducer/flattener has M56 threads. Therefore they can screw on together just fine.

The focus tube on the Sky-Watcher Evostar 80ED however has a diameter of 56mm, so it’s an M56 x 0.75 thread. The 0.75 thread pitch isn’t a problem here. It’s the diameter.

This isn’t usually a problem. The focus tube has M56 threads, and the matched reducer/flattener has M56 threads. Therefore they can screw on together just fine.

Attaching A ZWO CAA To A Sky-Watcher Evostar Telescope, the M56 threads of the focus tube and reducer fit perfectly

The issue arises when trying to attach the M54 ZWO CAA to the M56mm focus tube. It’s too large, and won’t be able to screw on.

How To Attach A ZWO CAA To A Sky-Watcher Evostar Telescope, however the M54 threads of the ZWO CAA do not fit.

The first step to overcome is finding an adaptor to fit the ZWO CAA onto the Sky-Watcher Evostar’s focus tube.

For this, I found an M56 to M54 adaptor from First Light Optics

This screws into the front of the ZWO CAA and will now allow it to be screwed onto the focus tube. Now, for the reducer.

How To Attach A ZWO CAA To A Sky-Watcher Evostar Telescope, now the M56 to M54 adaptor allows fitting to the telescope.

Next up I used an M56 to M48 adaptor I found on AliExpress.

I would’ve preferred an M56 to M54 to avoid any disruptions in the light path, but this was the best I could find in the mad rush I was in to make this fit!

The M56 threads go into the Reducer Flattener, and then the M48 size can be used to screw onto the rotator.

Once all items have been screwed on securely, the rotator is ready to be used with the camera and reducer/flattener.

Take care when tightening these adaptors in. I’ve found that the threads on astronomy equipment are extremely tight and it can be very difficult to unscrew afterwards. A little bit of light grease can be used to make this a bit easier if required.

Finally, screw the CAA on to the Sky-Watcher’s focus tube and use the locking collar to bring it to a tight and secure position.

You’re now finished attaching The ZWO CAA To A Sky-Watcher Evostar Telescope and can enjoy its benefits on a clear night.

Attaching The ZWO CAA To A Sky-Watcher Evostar Telescope

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