StarlightHunter

The filter is so near the camera if you thread the adapter in the 11mm ring (the one closest to the camera) that I think it should not be vignetting, or at least it should be something very light.

If you have the 2" one you can fit in directly in the rotator. It you have a 1.25" filter the best option is to use the adapter that came with the camera to put it inside the 11mm ring.

I'm sure it will workI was usin the same rotator/lattener/spacers/camera and you will achieve focus. Just a suggestion: use an IR/UV cut filter. you can thread it inside the rotator. That way you will not get very bloated stars.

I edited the comment as the image was not being shown.

Here you can see my setup. In the top-down order: 72ED without the 2" eyepiece adapter treaded to: Field rotator from FLO threaded to OVL flattener threaded to: ASI 294MC-Pro camera and spacers (using the OAG). The spacers I used with the camera are the ones in this image And I achieve focus without any problem.

Hi @fozzybear I've just rotated it counterclockwise like any other thread. If it is rock solid in your case maybe you will need to use some tricks. Apply some heat near the thread with a lighter and then, with a thick cloth in your hand try to unscrew it. You could also use WD-40 but that could spill over the lens and maybe damage the coating. No other ideas for that.

I'm using this rotator with a OVL field flattener in the old version of the 72ED with an ASI294MC and it works perfectly.

At least for me, I get focus without any problem. I attach the rotator, then the OVL flattener then spacers to get 55mm backfocus and then the ASI294MC-P. All works like a charm.

Ok. The best option here is to check on field I will need to find some time and clear skies to do some testing. Thanks!

Yes, That's exactly what I was asking. Thanks. I've an SW ED72 APO so I should need IR correction on a non filtered camera. Newts and non refracting telescopes do not need IR filters AFAIK. I was more concerned about reflections, focus problems or even less light coming to the sensor because of two filters being stacked.

Just to add more information to this flattener thread, it has a 2" thread on the telescope side so you can screw filters on it.

Ok. To finish this thread and to solve the problem I had, the real problem in my case was the ED72 not being well aligned. The focuser body was misaligned with the rest of the telescope because of a failure in the body attachment building. I just got a colimation eyepiece like the one of the photos and I was able to align the body and retight the screws so now it is well aligned.

Hi there. I recently adquired a ASI294MC-Pro camera and I read OSC cameras works better using IR/UV filters to avoid star bloating. I adquired two filters from Aliexpress, both of brand Svbony. One is the UV/IR and the other one is the CLS filter as I live in a very poluted area. The thing is the CLS is not a CLS-CCD filter, so it does not block IR, so I wanted to know if it is "wise" to pile up both filters so I can block IR/UV and city lights. Had anyone tried this before? I attach some photos of the CLS filter and a test I did with my DIY spectrographer

Yes. M56 female that fits directly into the rotator. About being rock solid, I just unscrewed it. Had not any problem doing it in my case. I think you will need to try tips and tricks for blocked nuts and screws.

Just for your interest. I recently bought an ASI294MC-P and using the spacers the flattener and the rotator all works perfectly and can achieve focus in the middle of the focuser length.