A week or so ago I had a whinge about the guide scope focuser on my ONAG
being a pain to focus in this thread
http://www.iceinspace.com.au/forum/s...d.php?t=119611
Then Prejto (Peter) pointed out this device on youtube
https://m.youtube.com/watch?v=YX-nyWe0qp0
Well, that was my eureka moment. “Put the camera in a focuser”
I had an old plastic focuser off one of those ebay 6” newts bought at the beginning of
my astronomy journey that I severely modified by adding all sorts of bearings and motorised
it. Sort of a rack and pinion driven crayford motorised focuser. Worked well in its day.
Anyway. Chopped off the plastic curve and fitted a couple of aluminium rings to clamp
a 1.25” nose piece. Reduced the length of the focuser tube and rack to suit and drilled and tapped
some extra holes to hold the camera. The unit had so many bearings that a locking screw to
hold the focuser in place wasn't needed. It worked brilliantly well. The focuser has about
35mm of travel so I move it about 15mm out then position the camera close to focus and tweak the
focuser for final focus. Takes about 30 seconds. And there's a bonus. Because it's used on
a newtonian scope if I use the X/Y platform on the ONAG to position the camera off to the side
the coma of the scope corrects for the distortion of the 45 degree mirror in the ONAG and
produces round stars. Hallelujah, it's christmas again!! Have been running it for a couple of
nights now and I've got a flex of about half a pixel per five minutes which I believe is the
main focuser assembly and not this gadget which is a dream to use.
Cheers
Stephen
