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Manuel rotator and ZWO asi 55mm space for camera.

Equipment Rotator Refractors
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Stuart myatt avatar
Stuart myatt avatar
Hi. 

I’m looking at getting  the WO Manuel rotator to frame easier and am looking to put it just after my scope and before my reducer / flattened on my WO ZT81. 

Will it mess with my focus at all for my camera and if so will i have to reduce the 55mm back focus distance to compensate?

thanks 

stuart
daywalker avatar
daywalker avatar
if you introduce another element then yes it will effect your backfocus.
You will have to find out the spacing of the rotator and then subtract that from yoyr current spacer setup. so that rotator + adapted spacer config = 55
Torben van Hees avatar
Torben van Hees avatar
if you introduce another element then yes it will effect your backfocus.
You will have to find out the spacing of the rotator and then subtract that from yoyr current spacer setup. so that rotator + adapted spacer config = 55

That's wrong. If he puts the rotator between focuser and flattener, backspace will be unaffected. It needs to be checked if the focuser has enough in-travel for this: Focus the scope with the flattener and image train and see how far the focuser is out. If it's less than the thickness of the rotator+all adapters, it will not work.
dreamsandmonsters avatar
dreamsandmonsters avatar
I just got the WO rotator 2.5" M63 threads for my WO GT 71.

I confirm that the rotator is between focuser and flattener, so it shouldn't affect backfocus.

Unfortunately, it's cloudy right now, but from what I saw on a Youtube video about this specific rotator, it doesn't change the backfocus, but it changes the focus point 22mm forward: https://www.youtube.com/watch?v=9iSk6CoYgfQ

Here's what it looks like assembled (and probably 22mm focused too far haha):
Rotator --> "2 step down rings" --> flattener --> adapters for 55mm backfocus distance --> filter wheel --> camera

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Eddie Bagwell avatar
Eddie Bagwell avatar
I also just purchased the WO 63mm manual rotator. Works great! Just mount it before the flattener/reducer just like in dreamsandmonsters pic. You can dial in the stiffness/smoothness by adjusting the small set screws on the edge of the rotator. Mine were too loose from the factory.
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Stuart myatt avatar
Stuart myatt avatar
I just got the WO rotator 2.5" M63 threads for my WO GT 71.

I confirm that the rotator is between focuser and flattener, so it shouldn't affect backfocus.

Unfortunately, it's cloudy right now, but from what I saw on a Youtube video about this specific rotator, it doesn't change the backfocus, but it changes the focus point 22mm forward: https://www.youtube.com/watch?v=9iSk6CoYgfQ

Here's what it looks like assembled (and probably 22mm focused too far haha):
Rotator --> "2 step down rings" --> flattener --> adapters for 55mm backfocus distance --> filter wheel --> camera


Many thanks for the reply. My concern is that my focus tube is only out by about 1CM and i think if i add the rotator that adds about 2CM to the train. I’m assuming i will have to go in on my normal focus by about 2CM to reach focus again.

Hope that make sense ha ha

thanks 
Taylor Ryle avatar
Taylor Ryle avatar
I have the Z81 and the rotator with the 6AIII and it achieves fucus with a centimeter to spare.
Stuart myatt avatar
Stuart myatt avatar
This is my issue
matthew.maclean avatar
matthew.maclean avatar
@Stuart myatt 
my GT81 is the same way. With the Flat6Aiii flattener, the WO rotator consumes too much distance in front of the flattener and it can no longer achieve focus.

I ended up using a M48 Blue Fireball rotator that sits after the flattener (and contributes to the 55mm back-focus requirement)
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jjpoole741 avatar
jjpoole741 avatar
Silly question, but is there any logic behind the way the angle indicator numbers are placed when installing it? 360 on top?
matthew.maclean avatar
matthew.maclean avatar
Silly question, but is there any logic behind the way the angle indicator numbers are placed when installing it? 360 on top?

It shouldn’t matter what orientation you call 0 (360); the only purpose to the angle scale would be so that, once everything is threaded together, you can associate the orientation of your camera with a particular number that you can write down so that you can easily return to  the same orientation if you wanted to collect more data frames in the future.
jjpoole741 avatar
jjpoole741 avatar
Silly question, but is there any logic behind the way the angle indicator numbers are placed when installing it? 360 on top?

It shouldn’t matter what orientation you call 0 (360); the only purpose to the angle scale would be so that, once everything is threaded together, you can associate the orientation of your camera with a particular number that you can write down so that you can easily return to  the same orientation if you wanted to collect more data frames in the future.

Thank you! Makes sense, but I just wanted to make sure I wasn’t missing anything.
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