Re: ATM Advise, please...

[glheiner@pacbell.net]

Bob Prabowo wrote:
> 
> Hi guys,
> 
>
> .....
> Now I need your advise on the followings:
> 1. Can I use a Newtonion telescope on Dobsonian mount for solar
> observing? Will an equatorial platform work for this kind of set up (the
> scope will be left unattended for hours)? Or does the scope have to be
> equatorially mounted?
> 

Hey, Bob, how about a truely unique sort of drive, one ONLY
suited for tracking the sun. No complicated mechanics (Dob is
fine, no need or advantage w/ EQ) or
electronics, not even any batteries or springs- in fact,
a virtually perpetual-motion drive, at least as long as the
sun rises. Why demonstrate 1 principle when you can do 2?

Imagine 2 closed plumbing systems, one for altitude & the
other for azimuth, filled with maybe alcohol or
even water & 2 pairs of solar collectors/baffles.  Spend a
little time
thinking & doodling, & I'll bet you can come up with a "drive"
that slighty alters the balance of a low-friction dob in the
desireable direction when the scope is pointed anywhere but
directly at the sun!

Maybe easier, better, & "funner", take a solar electricity-
powered approach & still be "perpetual".

       END VIEW
          ___ <-- Tabs guarentee small equal shading when
           |    pointed at sun, tabs bendable for response adjust
           | <--Wood or sheetmetal baffle, aluminize
           |  both sides via aluminum foil & contact cement
       ____|____ <--2 or 4 solar cells, 1 or 2 each side of baffle
       
You'll need 2 of these, of course, both mounted on the tube 
perpendicular to each other w/the wires running down to the motors.

Something like the following wiring may work correctly-

          D1            D2
    |-----|>|-----x-----|>|-----|
    |             |             |
SC1 |     1.5 v.  |             |
 ___|___   DC motor>           _|_ SC2
   ---             >          -----
    |              >            |
    |             |             |
    |_____________|_____________| 

-or maybe the cells wired back-to-back, or at most, some bridge
arrangement or 2 opposing motors- anyway, it's basically simple,
whatever the correct solution. (Where's that center-tapped DC
motor when you need one?:) 

You'll need 2 of these, of course, 1 for each axis. Now
that I look at it, at least 2 or maybe 3 cells wired in
series may be needed on each side of the motor.
The diodes may not even be neccessary, or maybe I'm not
thinking clearly (haven't had my coffee yet this morning:) &
this ain't quite the right way to do it.  So let me know if
this approach appeals to you, and if so, I run over to
Radio Shack & I'll put together something that WILL work &
send you the details, okay?  My treat, the parts are peanuts,
and I admire the work you've done & are still doing over there,
especially under sometimes less than ideal conditions.  I think
I have a very good idea of how to mount & gear down the motors
that's real low-budget too, let me know if you're interested.


Gary Heiner