12/18/2000
- Big jump tonite! Spider came! I finally measured and cut the
focuser hole. I calculated and measured like six times. First couple
times I got it wrong. Formula is half outside tube diameter + focuser
height + 1" for eyepiece. If that number is x, then do x + distance
from back of rear bulkhead to mirror surface, say that's y. Focal
length - y = distance from rear to center of hole for focuser. Gotta
do the math several times to be sure.
I also measured where to put holes for spider. It's going to be tricky.
I screwed up and had the guy make the spider for 1/4" plywood!
But I think we are still within limits, margin of error. If not I
can countersink the holes a bit.
Mirror (primary) was a little off, collimation time is coming. To
calculate spider hole position I measured the distance from bolt to
bottom of secondary, then half width of tube--tough! Anyway, tomorrow
she goes in! |
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12/20/2000
- It's done! Pretty much. I attached finder scope and handle on
tube. Spider was too short so I ran around and found plastic bolts
that I could cut and drill - they were toilet seat bolts! They even
had a round, flat part near the tip, perfect target for drill, and
guaranteed spacing. White, tho, oh well. Nailed Teflon to base, but
it was a little tippy at 45° or so, so I have glued some foam
pads to the top. It may be too tight and might pull the pads off.
Have to wait til tomorrow. But I looked at stars! First light on December
20, 2000! Magnification is not too high. I think I saw a planet. Anyway,
it appears the focuser position was correct! Score! Also, collimation
was really easy with the cell design. Thanks Richard Berry! Now-gotta
get another eyepiece maybe 7mm for some 200x mag! Cool-- |
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Our neighbor
Charlie was a big help
|
Some Notes:
I have no technical background and am terrible with math. But the
Berry book tells you pretty much all you need to know about building
a telescope.
I bought the eyepiece and primary from Orion,
and the spider and secondary from University
Optics. I ordered the Teflon pieces and Ebony Star formica pieces
from Russ Durkee
over the Internet.
All of the wood and most of the nuts and bolts were bought at Home
Depot. I used Spar Urethane for the varnish and flat black latex outdoor
paint for the inside of the tube and the base/rocker.
Hell, if I can make one of these, anybody can! |
