For those of you who know me, you know I am an amateur astronomer (besides dabbling in woodworking, writing, art, etc…). I started an astronomy blog here at WordPress lately to post pictures I’ve been taking through my telescope and other tidbits. I thought of a way yesterday to merge my two biggest hobbies, astronomy and woodworking.
I decided to make a base for my Telrad reflex sight, to fit atop the Texas Yard Cannon. And, to make it that much more fun, I decided to make it out of wood! Below is the post I posted yesterday on my astronomy blog…
If you have a telescope, chances are someone’s recommended using a Telrad reflex sight instead of (or in addition to) a typical finder scope. It looks a little funny—a blocky kind of thing with a little viewing glass on the back. When you line it up right with the Optical Tube Assembly (OTA) you simply peer through the glass and see a glowing red bulls-eye pattern with concentric circles. Center the star or planet you’re looking for in the bulls-eye and boom—said object is in the field of view (FOV) of your eyepiece.
That’s how it’s supposed to work. In theory. Many people (myself included!) seem to have a bit of difficulty using the device because it sits fairly flush with the telescope body—you have to bend over and crane your neck a little to sight along the OTA and see through the Telrad. It’s even worse if you have a finder scope sticking out of the side of the telescope. Like me.
My Yard Cannon has an 8×50 right angle finderscope that sticks up off the OTA about 6 inches. And of course it’s in just the exact spot that I’d like to put the Telrad—with both attached, not only is the telescope top heavy but it’s almost painful to use either method of finding targets (or both) while observing.
So, I finally had enough of bumping the finderscope while filming the planets and especially when storing the scope. My solution? remove the finderscope all together and install the Telrad on a base that utilizes the base for the finder that is already attached to the OTA. The tricky part? Making a base (of wood) that will either connect to the base or go over it.
I chose to use the base of the RA finder and carve wood to fit it. So I pulled a scrap piece out (from when I built my workbench—that adventure is on my woodworking blog, which you can read about here) and carved a dovetail into it that would match the base. I used some chisels and a rubber mallet and in about 10 minutes, I had this:
Then I flipped it over and worked the other side:The picture is kinda blurry (sorry, cell phone) but you get the idea—I created a nice little dovetail notch to fit the RA finder base. I decided to test fit it and it was just a tad bit too thick. Here’s where it’s going:After cleaning up the cuts a bit to remove some excess trimmings and some monkeying with the fit, the carved wood slipped in perfectly and was nice and secure with the set screw. It will make a perfect bed for the base of the Telrad to be attached.
However, the piece of wood I used was just a little too thin—the base of the Telrad will partially cover the set screw if I use it in this position. So, I cut me another piece of wood and glued it to the dovetail carved piece. Once that’s been shaped and trimmed to length, I’ll mount the base of the Telrad to this wooden piece and the Telrad will finally (I’ve had it for about 4 years and used it twice because of the awkwardness of working around the RA finder) get some love!
I’ll admit, it looks kinda wobbly, but nothing is glued together and it’s still in the rough-cut phase. I’ll pretty it up, never you mind…