In late 1997, Sharon and I visited my sister Jen and her boyfriend Chris (now husband) in San Francisco. She lived in SF proper, in the Noe Valley neighborhood which is near the Castro. One evening while we were out for a walk, we came across some amateur astronomers who had set up their telescopes on the sidewalk, for anybody to peer into. I took a look and decided right there that I really needed to get a telescope.
Turns out that they were part of a group called the Sidewalk Astronomers. They have free plans for a telescope that you can build, called a dobsonian, designed by John Dobson. You just need to mailorder the glass parts (about $200) and spend about $40 at the hardware store. So a couple months later, in Spring 1998, I gathered the parts and spent a month of weekends building the thing. This telescope design (a Newtonian) is simple but big, so I sized it to just barely fit in the back seat of my car.
The detail pictures here show how, uh, low budget this is.
Note the fancy bearing made of plywood, although I'll admit that there's a couple small pieces of teflon in there (that was a later upgrade, actually). See the secondary mirror suspended in the top end of the tube -- I think those three legs are made of paint stirring sticks.
It certainly looked pretty good after I got around to painting it. And note the bungie cord holding the mirror in place! The big primary mirror is supposed to just lay on the bottom of the tube, but when transporting the tube horizontally, or aiming at something very low, the mirror tends to flop around, which can damage it.
The bungie cord simply keeps the mirror from flopping forward, and doesn't really degrade the image so I just left it there.
We don't have much to see from intown Atlanta due to light pollution, but I've taken the scope on a few trips out of town (camping and the like) and have been able to use it a bit. Frankly, though, it's been a pain because A) it's really hard to find the object you're looking for, because manually moving the scope is so crude, and B) once you've found the object, the rotation of the earth under you causes the object to quickly drift out of view.
Last summer we went to a family get-together in West Virginia (right in the middle of the NRQZ), so I was really looking forward to the dark skies there. Alas, a full moon was up (washing out the dimmer night sky objects), and there was patchy cloud cover. And this was on top of the frustrations I've already mentioned. So, after 11 years of using the home-built scope, I decided that it was time to invest in a real telescope.
Modern commercial telescopes come with motorized electronic controllers that A) zip you right to the desired object (pick from a list) and B) slowly turn the scope to compensate for the earth's rotation. However, in doing research, I saw that I didn't know nearly enough to be able to make an educated decision on my purchase. And we're talking about a significant amount of money here ($1000-$1500), so as an interim step I decided to buy a smaller scope used. More about that in the next blog post ...
For now, this is my testimonial on my first telescope. After today, it's going to see service a lot less often. I'll still bring it out occasionally when I've got people around and multiple scopes will be useful, but for the most part it is now retired. Thanks go to John Dobson and the Sidewalk Astronomers for getting me started!
Forgot to mention ... this is the telescope that I used for The Hawk Channel!
http://intermod.typepad.com/intermod/2005/06/the_hawk_channe.html
Posted by: Chris C. | May 03, 2009 at 12:37 AM