Michael Wood wrote:

On 22 Feb 2004 16:39:41 GMT, (Rod Mollise) wrote:

OTOH I suspect the deep cycle batteries might be better for higher
current drawing equipment, like a dew heater system.


Hi:

Or maybe not even then. I've been using one of the Walmart yellow "Prestone"
jump start packs for a couple of years to power a goto scope and a Dewbuster
heater system. Never have had a problem. I do recharge in the mornings, though,
and if the setup includes a CCD camera, computer, etc., a big deep-cycle
battery is definitely recommended.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
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Rod,

My more than gracious wife has a agreed to buy me the NS11 GPS for my
50th bday this year. Have been considering the the Orion "Dynamo" or
the Celestron twin because they're made for powering these scopes. I
admit, I don't know a great deal about batteries and my concern with
buying something at KMart or Wal-Mart is that I will somehow fry the
electronics and then negate the warranty. Most are 12 volt so should
I just be watching the amps or what.

Just make sure that you have sufficient battery capacity (expressed in
amp-hours) to run your telescope and accessories for your observing
sesion. More is better. The Celestron and Orion power tanks store 7
amp-hours. My Target Greatland power tank puts out 12 amp hours; my
Celestron 114GT draws .75 to 1 amp, so my power tank can in theory run
the scope for 12 hours to 16 hours. The Celestron/Orion tank would power
the same scope for 7 to 9 hours. A scope plus accesssories that draw 2
amps would run 6 to 8 hours on the Greatland and 3.5 to 4.5 hours on the
Celestron.

Hope this helps you.
--
Pat O'Connell
[note munged EMail address]
Take nothing but pictures, Leave nothing but footprints,
Kill nothing but vandals...