Re: [ATM] water drive

[Dominic-Luc Webb <dlwebb@canit.se>]

On Tue, 13 Jun 2006, Mel Bartels wrote:

> > Why couldn't a small amount of water be used, say a quart or
> > less, and the drained water just be poured back in periodically?
> > Or would that introduce periodic error?
>
> Let the scope's weight push the water back into the reservoir, then use the
> reservoir to raise the scope back up to starting point.  A perpetual motion
> drive!  I hereby claim patent on this in behalf of the ATM list.
>
> Mel Bartels


Yes, this practice would tend to cause ripplies, causing stars and
even entire galaxies to bounce around across thousands of light
years of space. Clearly Mel's perpetual motion drive is superior! My
seemingly trivial water drive query has rocked the universe and ushered
in a patent for a perpetual motion machine in less than 24 hours,
assuming we have not distorted the space time continuum. Wow!

Seriously, I wish to point out I have built and used motorized drives,
and generally like them. But where I actually use the scope is in an
rented space in agricultural area where electricity is not available
throughout the Winter. Because I am at about latitude 60, Winter is
the main time to use a scope for usual observations. During this time,
it is cold, often bitter cold. Temperature can have large fluctuations.

Batteries do not last long.
Motors stall.
Mechanical parts seize.

When you are out in the cold, seeing these failures, you start asking
questions like:

Can I eliminate the battery? (solar energy is not an option here)
Would a hydraulic/pneumatic based system, etc work better?
What is the minimal mechanical construct that will work?

For a small portable drive, I plan to continue using electric
drives. For the observatory site without electricity, it is
not clear. I could consider some of these alternatives. I would
like to have what batteries I have allocated to CCDs, heaters to
remove dew, and a computer.

As an aside, I considered solar panels for charging. Here in
Sweden, they get stolen from these remote sites as fast as they
can be installed. I think it is a fundamental problem that these
areas are typically clusters of summer cottages that are closed
down during the Winter. During the Winter, teenagers break in and
use these places for parties, often breaking or stealing whatever
they come across. This ended up being a major design parameter.

Dominic-Luc Webb



_______________________________________________
ATM mailing list http://www.atmlist.net/