Re: ATM beginner projects

[wattsworth@juno.com (Eric Eggleston)]

On Mon, 14 Dec 1998 22:22:44 -0500 "William A. Morgan" <sass5@erols.com>
writes:
>1. Can the a/c motor like the one I described work with a rheostat, 
>say a house hold dimmer switch to slow or vary the rpm's? 

As a renewable energy engineer (new to this list) I can say the answer is
a big no. AC motor speeds are governed by the grid frequency they see,
not the voltage, so a rheostat won't work. You would have to have a
variable speed inverter drive system which is very expensive.

Greetings all. About 25 years ago, when I was about 11 years old,  I
ground (with much help) a 8" about f8 Pyrex mirror with the San Diego
Astronomy Club in the basement of the Space Theater in Balboa Park. (I
still have a observation plot at the club's property, which I haven't
seen in over 10 years)  In the fullness of time I finished the telescope
and did some viewing. Years later the cardboard sonotube was shriveling
and I took all the optics out and stored them. Now I find myself living
to rural Texas with a great sky, very little light pollution, and a
hankering to do some more observing. I'm also taken with the idea of
making a 4" or 5" refractor, but find the objectives very expensive.

Questions:
1. Is there a good source for a 4" or 5" refractor objective at a price I
can afford?
2. Is it possible to grind my own objective? If so, where would I get a
kit?
3. Anybody want to talk me out of doing a refractor and into just
rebuilding an 8" reflector?
4. Anybody want to talk me into a 8" mirror for 5" objective trade?
5. Anybody need an 8" aluminized about f8 mirror? (I have access to two
of them)

Regards,

Eric Eggleston

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