University Lowbrow Astronomers

My First Telescope.

by Donald Fohey
Printed in Reflections: October, 2008.

The telescope

Many of the firsts in life are fondly remembered. For many it’s their first car and for astronomers it’s their first telescope! I still have mine, stuffed in the rafters of the basement and in a moment of sappy nostalgia, I pulled it down to take a look at it. I made it in either 1968 or 1969. I will never forget that first view of Saturn’s rings through this telescope. It also provided my first view of Jupiter and it’s Galilean moons. It still works every bit as good as it did 40 years ago.

A casting resin was used, some kind of epoxy, glass cloth in a 2 inch wide roll, plumbing pipes and plumbing drain tubes. I did have limited access to a metal lathe at my college job internship. The project was built from lenses and booklets from Edmund Scientific which is still in business today!

Objective Lens

Directions for Mounting your Air-spaced Achromatic Objective

Objective Lens

The objective lens is a 2 inch diameter 50 inch focal length air spaced achromatic lens. Yes that is an f25 objective. The lens cell was made by casting resin into concentric tin cans and then machining with a lathe to obtain the final dimensions.

Tube

Build this 2 inch refractor

The tube was built from the basic Edmund plan. It was made by wrapping the wood stringers with 2 inch wide glass cloth and then coating the glass with an opaque brown epoxy. I remember this being very messy as the epoxy dripped off the tube as it was curing.

Mount and Tripod

Instructions for building the tube

Mount and Tripod

The tripod and mount construction followed direction from the famous Edmund booklet No 9082 “Mounting Your Telescope.” Pipe and pipe tees were machined on a lathe to make the equatorial mount. The counter weight was made by melting and combining tire balancing weights. At that time without consideration of lead poisoning.

Eyepieces

Eyepieces

The eyepiece

The light cone of an f25 lens doesn’t place a high demand on an eyepiece and a 1/2 inch f.l. eyepiece will yield 100 magnification. I purchased from Edmund plano convex lens pairs for Ramsden eyepieces. The lens mounts were made from casting resin and then assembled into tubes cut from 1 1/4 inch drain tube. Focus was obtained by sliding in and out a section of telescoping drain tube.

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Copyright © 2013, the University Lowbrow Astronomers. (The University Lowbrow Astronomers are an amateur astronomy club based in Ann Arbor, Michigan).
This page originally appeared in Reflections of the University Lowbrow Astronomers (the club newsletter).
This page revised Sunday, March 9, 2014 4:30 PM.
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