Quark modification- fully screwed connections

[Zakalwe]

Anyone that knows me will know that I have a pathological hatred of the crummy method of holding cameras/eyepieces/filterwheels and so on in focusers. Single screw clamps are the work of the devil and those flimsy brass strips that inhabit focuser clamping arrangements seem perfectly designed to jam most things. There's no standard for undercuts, with some manufacturers using tapers, some putting the undercut exactly where the screws clamp and some too narrow for the brass strip.

Twist compression clamps are better, with the Baader twist-lock being a "proper job", but none are as good as a proper threaded connection from the focuser to the camera.

I always have a nagging paranoia that an expensive focal reducer, filterwheel and camera will fall out of any focuser that uses clamping screws or compression clamps. If that wasn't bad enough, then most clamping screws have the annoying habit of tilting the imaging train, or introducing slop. This is a BAD THING, especially on fat 'scopes with their narrow focal plane. It's even worse in hydrogen-alpha imaging, as tilting can knock the kit off-band.

Daystar seem to have made a bit of an artform of producing the worst possible clamping arrangement when they designed their Quark. The eyepiece/camera clamp uses a horrible single screw arrangement that is impossible to use without it tilting the camera. Plus, the thread that they used is an archaic threadform, not the far more common T2 thread. Luckily, there is now an adapter on the market that allows a T2 thread to be fitted.
Now, my focuser has a M63 thread at the rear, which thankfully, is becoming more popular. My scope is an Altair Astro 115mm triplet, which uses this focuser: http://www.teleskop-express.de/shop/product_info.php/info/p2526_TS-3--Crayford-focuser-for-big-Refractors---1-11-Micro-Tansm-.html
Most Quarks that I have seen also need an extension tube to get focus. I've used 2" extension tubes that have twist lock clamps at one end.....they are OK, but still allow for a bit of tilt.
I have been speaking with Mark at JTW Astronomy and we've designed an adapter that not only screws into the focuser, but which also allows a 2" UV/IR or Baader H-a filter to screw into it as an ERF.





To use it, screw in the UV/IR filter at one end, remove the 2" barrel off the Quark and screw the Quark into the adapter and then screw the whole shebang into your focuser.



Hey presto, a fully screwed, orthogonal imaging train right through to the camera.



It's a heck of a lot more solid than the extension tubes and clamps and I KNOW that everything is properly in line. I won't get a chance to "first light" it until the weekend but I am very pleased with how this turned out! Big thanks to Mark for taking my scribbled drawings and turning it into a properly made piece of kit!

[michael.h.f.wilkinson]

Looks very good!

[Luke]

Perfection! Look forward to seeing the fruits of your labour!

[msh1]

thats sort of what i need im of to see john who makes the adapters for flo tomorrow see if he can knock me something up 

mark