110 replies to this topic

[JimTheEngineer]

Both the new SQA85’s I have used did not have any issues like this.

It's probably all the translation difficulties. When using the fine focus knob, the image randomly shifts. Adjusting the screws does not improve the results, except when pressed hard, the focuser stops moving.

[TravelingWave]

Both the new SQA85’s I have used did not have any issues like this.
 

Did you manage to order a new precise parts adapter that works with the CAA?  I have an SQA106 but just realized the manual rotator is in the way. I didn't realize that was going to be an issue when I ordered. I wanted to use the CAA with an OAG and 2 inch filter wheel.

Edited by TravelingWave, 06 May 2025 - 04:45 PM.

[JimTheEngineer]

I haven’t figured it out. Sharpstar tried offering some suggestions, but they did not work. When you take the manual rotator off, the “hole” of the PreciseParts adapter must be larger than the focuser inside that tube as the focuser moves out. I think you will see what I’m talking about racking the focuser fully out with the manual rotator off. I do need to double check what an M68 “hole” would do and check my M54 OAG spacing - but I’m not optimistic. Have had 5-6 weeks of cloudy skies in Houston, so haven’t done much with the equipment lately…

I’ll PM the Sharpstar conversation. They were helpful and responsive, but no solution yet.

BTW - I think you will really like the optical quality of your scope. My SQA85 has tiny stars and no chromatic aberration on an APS-C sensor. It’s definitely a keeper. If M68 clears, I think only a Falcon would work with the OAG. Maybe I’ll breakdown and install a guide scope, but hate to mess up my perfect 0.2-0.4” RMS guiding, so I may sell the CAA…

Did you manage to order a new precise parts adapter that works with the CAA? I have an SQA106 but just realized the manual rotator is in the way. I didn't realize that was going to be an issue when I ordered. I wanted to use the CAA with an OAG and 2 inch filter wheel.

Edited by JimTheEngineer, 06 May 2025 - 11:09 PM.

[JimTheEngineer]

I figured it out! The issue was the rear lens cell with an OD of 51.25mm would not go thru the PreciseParts adapter ID of 51.0mm. I contacted Ashley and he said he couldn’t help since any removal of any material would create an unsafe condition. I needed only about 0.5mm. So I used a dremel and sanded off the baffle ridges and paint. Hand sanded a little bit more. This was enough to get clearance of the rear lens and an additional 9.5mm of inward focus. I needed 5.8mm as per the diagram below.

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Edited by JimTheEngineer, 09 May 2025 - 11:03 PM.

[JimTheEngineer]

Based on my EAF set to zero on maximum inward focus, I have 869 steps at focus. My typical step size is 10 and I seem to remember my focus varies by 300 steps during an evening. Not sure about seasonal shifts, but tonight it was probably within about 10-15degF of maximum temperatures and 40-50deg from minimum temperatures. So I think it’s very close, but it is working.

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Edited by JimTheEngineer, 09 May 2025 - 11:58 PM.

[TravelingWave]

I figured it out! The issue was the rear lens cell with an OD of 51.25mm would not go thru the PreciseParts adapter ID of 51.0mm. I contacted Ashley and he said he couldn’t help since any removal of any material would create an unsafe condition. I needed only about 0.5mm. So I used a dremel and sanded off the baffle ridges and paint. Hand sanded a little bit more. This was enough to get clearance of the rear lens and an additional 9.5mm of inward focus. I needed 5.8mm as per the diagram below.

Looking at the SQA106 I have my dimensions are going to me different. 

 

The inner diameter will be around 80mm to clear that black cylinder that moves inside the outer silver casing. The outer diameter needs to be about 87mm.

 

Could you post the name of the precise parts adapter so I can reference it when requesting the dimension change to precise parts?

 

Great you figured it out! Thanks!

Edited by TravelingWave, 10 May 2025 - 08:47 AM.

[JimTheEngineer]

You can use “build and adapter” on the PreciseParts website. Choose Askar and ZWO then Askar SQA85 Drawtube and ZWO CAA M54. You might have to provide your SQA106 rotator tube details for Ashley to add this.

https://www.precisep...in/adapter-ctrl

All I was worried about was getting past the first lens which was 51.25mm OD with a depth of only 7.5mm. So if your rear lens diameter is larger on the SQA106, you might not have this option unless you go with a larger diameter rotator. Check the math for your SQA106 after you get stars in focus with your normal setup (the pic above of the yellow piece of paper).

The pic of the adapter and lens cell prior to the sanding to increase the ID of the PO adapter is attached.

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Edited by JimTheEngineer, 10 May 2025 - 01:22 PM.

[Radinkel]

Hi Jim,

Interesting topic! Thanks for sharing! I have the same backfocus problem, but I'm using a PegasusAstro Falcon V2 as rotator, which has an M68 female thread, so there's more room for the flattener. So an adapter from M74x1 to M68x1 should work?

Ralf

[JimTheEngineer]

I would think so for the SQA85. However double check all your dimensions. The CAA is 16.5mm backfocus and I needed 13mm for some extensions for the Askar M54 OAG overhang.

I haven’t confirmed all ambient temperatures yet to make sure the 869 steps remaining for focus is enough (my EAF focus routine has a step size of 10). However, I’m only about 10-15degF cooler than high temperatures.

[TravelingWave]

You can use “build and adapter” on the PreciseParts website. Choose Askar and ZWO then Askar SQA85 Drawtube and ZWO CAA M54. You might have to provide your SQA106 rotator tube details for Ashley to add this.

https://www.precisep...in/adapter-ctrl

All I was worried about was getting past the first lens which was 51.25mm OD with a depth of only 7.5mm. So if your rear lens diameter is larger on the SQA106, you might not have this option unless you go with a larger diameter rotator. Check the math for your SQA106 after you get stars in focus with your normal setup (the pic above of the yellow piece of paper).

The pic of the adapter and lens cell prior to the sanding to increase the ID of the PO adapter is attached.

How did you remove the lens? Is there a special set of pliers that fits into the 2 holes of the piece to unscrew it?
 

[JimTheEngineer]

Mine is and was just hand tight. So no tools required on mine. It does have slots for a spanner, so you can try that if you have any issues. I use one that looks like this.

https://www.amazon.c...435179098&psc=1

How did you remove the lens? Is there a special set of pliers that fits into the 2 holes of the piece to unscrew it?

Edited by JimTheEngineer, 15 May 2025 - 08:03 PM.