150 Wh Power Station for $105:
https://www.cnet.com/news/be-ready-for-emergencies-with-this-acdc-power-station-just-105/
This device appears to be perfect for taking to the field. It includes 12
VDC ports, USB ports, and two 120 VAC outlets.
On Fri, Sep 7, 2018 at 12:31 PM Paul Lind <pulind@xxxxx> wrote:
My camera gives percentage cooler power in the Maxim-DL program screen. I
haven't really measured the actual current. Inside my shop cooling from
80F (26C) to -15C -> 41C cooling, the readout says 80 percent. I think I
got good cooling outside on a 50F (C) degree night, cooling to -15C with
it reading 60 percent. That's 25C degrees cooling. It seems to indicate
that your cooler will run at about 50 to 60 percent of max when observing.
If it's quite cold outside it will take less. Also, some people like to
cool to -20C or lower. I've been using -15C for my 5 minute exposures.
As far as using a stepper motor to drive a focuser, an important thing is
to allow manual focus by means of some sort of clutch. There are
commercial add-on units that come as either pushbotton control or USB
control from a focusing program. I recall that Al Stiewing mounted one of
those on a short refractor.
----- Original Message -----
From: Michael McDonald <mikemac@xxxxxxxxxxx>
To: az-observing@xxxxxxxxxxxxx
Sent: Thu, 06 Sep 2018 19:05:22 -0400 (EDT)
Subject: [AZ-Observing] Re: Telescope power
Hi Paul,
Yeah an inverter would make interfacing all of the supplies a lot easier.
Unfortunately I donât have a camper so I would have to carry the batteries
over to the telescope. (Iâll need the space in my âbedroomâ!) At 60 lbs
a
piece, that doesnât sound like fun.
I wonder if the power draw of the cameraâs cooler drops off dramatically
once it has reached the set point? I think my devices will use about 7A,
peak. With a single 120Ah battery, thatâd give around 17 hours of use. That
might be enough for a two night trip.
Mike McDonald
mikemac@xxxxxxxxxxx
PS For the ATM meeting on the 18th, start thinking of ideas on how to
attach a stepper motor to my Celestron C6 (SCT) for automating the focuser.
Thatâs going to be my next project. If I can decide between gears or
pulleys.
On Sep 5, 2018, at 4:39 PM, Paul Lind <pulind@xxxxx> wrote:for two or three nights. This comes from two 110 Amp-hour "deep-cycle"
Michael,
I take a lot of power-hungry equipment out with adequate battery power
batteries from Walmart connected in parallel. They remain in my small
camper. I convert the 12 volts to 120 volts for use on long extension
cords to the scope, where I power my computer and a 12 volt 5 amp Japanese
power converter to supply 12 Volts at 4 amps to my telescope. That
includes a cooled Apogee camera ( 3 to 4 amps at 12v) and about 0.3 amp
clock drive. With this arrangement I don't have to carry heavy batteries
out to the scope, but it does cause as much as 20% total loss in the
converters. The batteries weigh about 60 lbs each.
Paul Lind
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