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Originally Posted by Starkler
I upgraded the crayford on my dob to a new one with 10:1 fine focus control, so the old crayford is going on the R130  |
Done and maybe looking a bit silly
On this rather lightweight scope the gso crayford is a big heavy thing.
Its mounted on whats basically a wooden box of a suitable height to get the right focus range for the eyepiece combinations that I use.
I started by covering the old focuser hole with a piece of paper with a small centred hole to aid alignment with a laser. I marked the point geometrically opposite on the wall of the ota with a small dot of white paint .
Then came a lot of work with a dremel and sandpaper to get the feet of the wooden box square so that the laser lined up and the new focuser square.
I did some other mods relating to the spider assembly. The collimation screws as supplied had a conical tip with a small hole in the middle designed to bite into the metal
, which is exactly the opposite of what is desired.
These screws had made divots in the aluminium secondary holder, making it impossible to rotate the secondary to fine tune collimation.
I rounded off the edges of these screws with the dremel, and I made up a washer made of thin steel which sits between the collimation screws and the secondary holder. Much nicer
I also added flocking material opposite the focuser and around the bottom end of the ota. You can pick it in the second photo.
So does this focuser look like an overkill or what?