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TS basic Newt focuser.


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Sir Isaac, our 20 inch Dob, has been under the weather of late and neglected because of the rival claims of the imaging rigs. Time for a little TLC!

First one of these;

Telescope-Service: Focusers

Simple, honest, decently made and free of play. What is more the fixing holes were in the right place so what more could a man ask for? One of the underside screws disengages the drive and locks the drawtube (a good idea) while the other controls the friction. My only concern is that those not familiar with it might overtighten the pressure adjuster thinking it is a lockscrew, but on a Dob nobody locks drawtubes anyway. The action is smooth and the drawtube free of sag or play.

Next I collimated the laser, a Telescope House one from years back. A thousand thanks to the bright spark who suggested making V blocks by banging two pairs of nails into a plank so that they cross over. Ten seconds later, perfect V blocks! Brilliant. Another pearl of SGL wisdom doing the rounds.

And 2 minutes after that, a well collimated laser. It is adjusted by three small allen keys a la finderscope.

Back in Sir Isaac the nice accurate laser behaved far better than before because of the removal of flex inherent in the old focuser. I hope he will now be up to pouring light into the new 26 Nagler without the astigmatism I was seeing pre-facelift.

And right on cue an optics professional appeared on our doorstep so the final tweaks can have the master touch. Happy days!


Edited by ollypenrice
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