Homemade Non-Magnifying Finder
These are plans on how to build a very primitive non-magnifying
finder scope. Hopefully you won't need this at all, but many people
can't get the hang of using the "both eyes open" method with a
normal finder scope. If you have money to spend on a high-tech solution,
get a "Telrad" for about $50 US. If you're on a shoe-string budget, read on.
Here's what you need:
- Cardboard tube from a roll of paper towels.
- Sheet of heavy paper - black construction paper works well.
- Glue.
- Some rubber bands.
Here's how to build it:
- Cut out a disk from the paper. It should be just a little bit
bigger around than the paper towel tube.
- Cut a smaller circular hole out of the middle of the disk. It can
help to fold the disk in half while cutting. The hole should be about
one centimeter in diameter (a little over a quarter inch, a little smaller
than a US dime).
- Glue the disk to the end of the tube. It helps to apply a thin bead
of glue around the outer edge of the disk and then lower the tube onto it.
- Let it dry.
- Attach the tube to the telescope with rubber bands, keeping the tube
as perfectly straight along the line of the telescope as possible. The
open end of the tube should point toward the sky, the "glued disk" end
toward your eye.
Here's how to adjust it:
- During the day time, point the telescope at some easily seen landmark.
Center that landmark in the telescope's eyepiece. The top of a distant
evergreen tree works well.
- Put one eye up to the cardboard tube. Keep both eyes open!
Adjust the tube so that the landmark appears in the center of the
circle formed by the open end of the tube. This may require inserting
small spacers (bits of cardboard taped together) between the cardboard
tube and the tube of the telescope.
The biggest problem with this finder is that the slightest nudge will
knock it out of adjustment. I suppose I could glue it, but I don't
want the thing to be a permanent fixture on my scope. Perhaps some kind
of rubber cement that will stick fairly well but can be rubbed off
after use? Let me know if you come up with a good solution.
Fortunately, the finder doesn't have to be precisely adjusted. Just
so long as it gets the target into the view of the regular finder scope,
you should be all right. Of course, you still have to deal with the
upside-down view of the regular finder, but that's something you'll
just have to get used to.
By the way, would it be helpful to include a picture or graphic?
Or is it pretty easy to understand what I'm doing?
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http://www.geeky-boy.com/standard.html
then check it out now.