These are my tests on the ZWO CAA Rotator. Here is how it flexes and how the backlash works out. It's very good and adds very little to the entire system of parts.
I doubt we will ever see as detailed flex measurements as you have shown, thank you for taking the time to show the very small details in your video,the ZWO CAA will be a nice addition to our scope rigs, just watch how much weight is added to it. 👍
Excellent testing setup! When the CCA was being presented, your test addressed my main concern with the mechanical construction. I figured ZWO could build something with decent rotation repeatability, but was very concerned about how planar the camera would remain relative to the imaging plane. Your results seem to indicate ZWO did very good in that respect. Thanks for your due diligence on this testing.
I would be more interested in tilt introduced by rotator. Having micrometer I'd expect measuring tilt during rotation at least for the cage. And disassembly and internal structure are more interesting; it will help understand potential issues
A fun exercise; nice. I think you would’ve enjoyed Van Slyke Instruments. Long out of business due to fire and flood, Paul made amazing precision machined accessories for telescope optical trains.
A few things on using rotators. You need to tighten the threads a bit more than a non-rotating camera or the cable tension can start to unscrew it. The motor will then turn but the camera stays still. So give yourself lots of extra slack in the cables so they can move around and not get strung tight. Also make sure you have the camera angle in your file name so you can match your flats rotation - if you do several targets at different angles, it's easy to lose track of which flat went with each target. Enjoy!
@@JeffHorne As long as the threads remain tightened to the same degree, you should be able to return to any rotational angle between flats and lights. Your imaging app should be able to report the current angle of the rotator, and the PA angle in the sky after doing a platesolve. If you do a teardown and rebuild, you may need to recheck that the rotator angle and PA angle remain the same; you may need to re-zero the rotator if different.
Just do not assume it will do this accurately enough to remove dust motes on your focal reducer. But for vignette compensation it is plenty accurate enough.
This could also be your focuser tube. You need 2 dails, one on flattener and a second one on camera to test flexture. You are correct on rotation. I wonder if it is precise enough to do anti field rotation on alt/az ap system
That is why we did the same test without the rotator. You can subtract the flexure without it to get that number. Placing dials on two different spots will give more confusing answers because you fulcrum point is moved considerably farther away.
Good video, thanks We wonder if this accessory really exists..... Apparently this item is very rare. Shipments are done at random!!! ZWO really not serious!!!!
In retrospect I probably could have bolted something to it however when I pushed on the dial it did not move. Dial indicators apply very little pressure. That does vary though from brand to brand of course.
It is hard to tell what part of image train the weakest. It could be focuser, rotator, or even camera case is not tight enough. Also rotating and taking measurements on camera body is also far from precise as aluminium camera case may not be aligned with the image train axis.
It’s a place I spend a lot of time. Also i have never been in a dirty one that was profitable. Never been in a clean one that was not making a ton of profits.
I doubt we will ever see as detailed flex measurements as you have shown, thank you for taking the time to show the very small details in your video,the ZWO CAA will be a nice addition to our scope rigs, just watch how much weight is added to it. 👍
Excellent testing setup! When the CCA was being presented, your test addressed my main concern with the mechanical construction. I figured ZWO could build something with decent rotation repeatability, but was very concerned about how planar the camera would remain relative to the imaging plane. Your results seem to indicate ZWO did very good in that respect. Thanks for your due diligence on this testing.
Thanks for watching. I'm glad you found the information useful.
Very cool testing!!! We use the same equipment to measure vertical turbine shaft deflection. Hope all is well!
Cool! Industrial stuff just fascinates me.
Better than I expected. Thank you.
Thanks!
Fantastic! I hope you're well sir!
Thanks, I am!
Nice one Ben I hope you get to use it soon, it looks a nice size too as a lot of rotators out there do seem quite cumbersome.
Your right about the size.
I would be more interested in tilt introduced by rotator. Having micrometer I'd expect measuring tilt during rotation at least for the cage. And disassembly and internal structure are more interesting; it will help understand potential issues
That is what we are measuring here.
A fun exercise; nice. I think you would’ve enjoyed Van Slyke Instruments. Long out of business due to fire and flood, Paul made amazing precision machined accessories for telescope optical trains.
Familiar with some of their stuff. Yes they were good company.
A few things on using rotators. You need to tighten the threads a bit more than a non-rotating camera or the cable tension can start to unscrew it. The motor will then turn but the camera stays still. So give yourself lots of extra slack in the cables so they can move around and not get strung tight. Also make sure you have the camera angle in your file name so you can match your flats rotation - if you do several targets at different angles, it's easy to lose track of which flat went with each target. Enjoy!
Are rotators generally accurate enough to be able to properly reproduce a sufficiently accurate angle for flats?
@@JeffHorne As long as the threads remain tightened to the same degree, you should be able to return to any rotational angle between flats and lights. Your imaging app should be able to report the current angle of the rotator, and the PA angle in the sky after doing a platesolve. If you do a teardown and rebuild, you may need to recheck that the rotator angle and PA angle remain the same; you may need to re-zero the rotator if different.
Just do not assume it will do this accurately enough to remove dust motes on your focal reducer. But for vignette compensation it is plenty accurate enough.
This could also be your focuser tube.
You need 2 dails, one on flattener and a second one on camera to test flexture.
You are correct on rotation.
I wonder if it is precise enough to do anti field rotation on alt/az ap system
That is why we did the same test without the rotator. You can subtract the flexure without it to get that number. Placing dials on two different spots will give more confusing answers because you fulcrum point is moved considerably farther away.
Hi Ben, more please!!! I find you do videos that no one does! Thank you brother. Now for $299 hard to beat and how does it compare to the other CAA?
If they want to send me one i could do it. I am not sure i would ever use another brand though unless it worked with asiair
Excellent video, God bless
I appreciate it.
Hope your doing well!
I am! Thanks for asking!
Good video, thanks
We wonder if this accessory really exists..... Apparently this item is very rare. Shipments are done at random!!! ZWO really not serious!!!!
I am seeing them everywhere on social media so a lot of people have them now.
What about radial tilt caused by the motor backlash?
That can be deduced from the flexure difference measured between shots with the CAA and without.
Maybe measuring on black tilt adapter is a bit more precise.
In retrospect I probably could have bolted something to it however when I pushed on the dial it did not move. Dial indicators apply very little pressure. That does vary though from brand to brand of course.
Thanks for the video. I'm not sure people outside of the US knows what "a thousands" is about :-)
Maybe I should use wine barrel unites. haha.
It is hard to tell what part of image train the weakest. It could be focuser, rotator, or even camera case is not tight enough. Also rotating and taking measurements on camera body is also far from precise as aluminium camera case may not be aligned with the image train axis.
Subtract the measurements done without the CAA from numbers with the CAA and you can deduce that.
@@TheNarrowbandChannel that is actually good point.
Your workshop is way to clean. Throw some chips and oil around.
It’s a place I spend a lot of time. Also i have never been in a dirty one that was profitable. Never been in a clean one that was not making a ton of profits.