FOCUS LEVER
This is an incredibly easy mod that makes focusing at high powers a snap.
I made this mod when I was spending a lot of time above 200x with the
binoviewers in the focuser. That was a lot of weight to move around
precisely. Focusing with the stock knob induced a lot of vibration and was
difficult to control. So I added this little focus arm that essentially
turns my focus knob into one with an 8" radius.
Here are some pics:
The arm is
made of 1/8" x 1/2" aluminum. Steel was too heavy. I had to bend it a bit to
clear the binoviewers. This had the added benefit of clearing the finder as
well. The wingnut is used to activate or deactivate the arm. I can use the
focuser normally
without tightening up the arm and then when I am viewing at high power, I just
tighten the wingnut and focus on an 8 inch knob instead of a 1.5" knob. The
reason I did this was to allow a fine focus option at high powers. With the
focuser tight enough to
eliminate the play, I was getting a lot of tube motion when I was trying to nail
the focus. This should eliminate this.
I also made
a second focus arm that is a lot easier to use, but requires some searching to
make it work.
The gold part is just a cap from a can of spray paint
that I found in the garage. I cut the bottom half of it off to make it
less deep. It was the perfect diameter to fit the focus knobs on the
crayford focuser. I tried making a focus arm like this for the stock XT10
focuser, but was unable to procure a cap that fit the smaller XT10 focus knobs.
I was luckier with the crayford focuser knobs.
I used the
same aluminum arm and just bolted that to the cap. The black that you see
around the edge was electrical tape that I used to stiffen up the thin plastic.
I used just enough electrical tape to make the fit snug. If I put too much
tape on, it was too hard to remove the focus arm. Too little tape, and the
arm just slipped.
This
solution is much easier in operation than the wingnut version. But, it
requires some luck in finding the right cap.
