I think the question is about the little flange at the base. I'd guess it's only 2mm or so thick.

To NPB, why the concern? Are you trying to use a focal reducer or a flattener and have a specific spacing you are trying for?

With the ASI128MC in short supply or out of stock and seemingly discontinued, the new ASI6200MC-Pro, due late Jan. 2020, and similarly priced, would be the option. It's pixels are smaller, but with 60MP to play with, binning would somewhat address the pixel size issue.

Another handy tip. Thanks!

Ah, I see. Cool. Thanks for the clarification, and the how-to.

That's excellent!

Does not having a focus lock screw after the mod affect performance at all? With my focus lock completely loosened it seems a little sloppy. I usually leave that screw loose enough to adjust focus, but with a bit of resistance.

Thanks!

What brand and model of coma corrector are you using? Does it have instructions? Generally, there should be a specification for the coma corrector that tells you how much spacing needs to be between the corrector and the image sensor. Then you need to assemble the various spacers and connectors to m...

That's very helpful. Thanks Katherine.

Thanks Katherine. Just to clarify, you are saying that ZWO hasn't tested the EAF with the Star71, but a customer has used the EAF with a Star71 and it worked. Do you know if worked right out of the box, or did they need to do anything special or make modifications to get it to work? If it needed som...

Essentially, yes. If you used a full frame camera and an 810mm lens you would get about the same field of view as what you get with an ASI183MC and a 300mm lens. It doesn't actually make the 300mm lens an 810mm lens. It just changes your filed of view. It's referred to as "crop factor" because it's ...

As a related question, Is the EAF compatible with the WO Star71 (1st Gen) or is some DIY work required to use it?