Just experimenting with the secondary mirror knobs.
The Bobs Knobs are flat on the bottom, Now i could take them out and grind them to a ball but i decided to keep them flat and place a ball over them.
I found 3 grease nipples in a kit for heavy machinery cut the threads off,Unscrewed the nipple from the elbow.
The knobs now seat in where the nipple was set.
I found i had to do this as the knobs we cutting into the plate on the back of the secondary mirror.Also as i adjusted the knobs it actually turned the secondary mirror around.
My problem is now solved as there is 1 point of contact on each knob without the cutting effect.
So your scope has balls! Well done - and different!
Yes, Kev, I've previously noticed this as a weak part of these designs. I cleaned up the large metal washer (lots of screw marks chewed into it) and glued it to the plastic holder. Then I filed and emery paper'd the screw ends to a nice square, flat, shiny finish. That improved matters.
Of course, the whole concept of tilting the secondary so far away from the mirror surface itself is flawed! The secondary doesn't just tilt, it moves away from the axis somewhat. I have seen more complicated designs where the pivot point is very close to the back of the secondary. Then there is no room for a secondary heater in touch with the mirror surface.
Good idea Kev.
I've had the same binding with my secondary screws. I'l look an see if I have room to add the " Kev balls" Thanks for posting.
regards
Ed
Thanks for posting.
