DIY guidescope rings

[discardedastro]

So, yes, OAG is always going to be better than a guidescope. However, I have a guidescope, camera, etc which all works fine - except for the differential flexure...

I was using a set of Primaluce Lab guidescope rings. They're pretty bad. Through filing off all the plastic tips on the screws, and slathering everything in Loctite, I managed to overcome some of the failings but they still basically aren't made well - the threads are loose, the screws don't fit well in the threads, the tips flex, and so on.

I've got an ADM dovetail and clamps, which are perfect. No change needed there.

So figured, hey, I know a guy with a collection of CNC machines who needs more projects - and hacked together a CAD design that looked like this: https://myhub.autodesk360.com/ue29fa843/g/shares/SHabee1QT1a327cf2b7a5a22a1be63168b5b

He cut those for me the other week and after a bit of sanding to bring them into final dimensions I have a very tight fitting set of guidescope rings:

  

Time will tell if these actually fix my differential flexure problem adequately - I only fitted them today - but they feel much more secure. I'm a little concerned about pinching the optics but for a guidescope stable but slightly defocused is preferable to wobbly, so I've erred on the side of caution so far - can always take them off and sand them back another few tenths of a mm. My other thought was to take them back half a mm and line with some fine felt or plastic, but I didn't think this would actually help the stability side of things.

One more thing - he's now played around with the design a bit more (beyond just replacing my captive nuts with cut threads) and is considering making more if anyone wants any, so drop me a PM if you do. The finish on these wasn't great, but he reckons he's got a better way of doing them in future which will give a nicer finish.

[michael8554]

Pinched shouldn't matter as you said, but you could look at the star shape and Profile as you tighten, back off a tad if you see signs, and decide whether it's tight enough to eliminate flexture.

Michael 

[discardedastro]

Just now, michael8554 said:

Pinched shouldn't matter as you said, but you could look at the star shape and Profile as you tighten, back off a tad if you see signs, and decide whether it's tight enough to eliminate flexture.

Michael 

Yep - I'll fiddle around a bit when I get some skies to work with. It's very snug at present.

[michael8554]

The right size for mounting a PST solar scope on a mount might be useful for some.

Michael