Hi Rolando,
With the recent discussions about
eliminating excessive dew formation on the (CP3 to CP5) controllers, and
everything else under a scope tarp, I thought I would (finally) ask THE
EXPERT, master optical craftsman, just ...
what should be the “ideal Relative
Humidity Level” for Optics and Electronics, while covered
in outdoor storage (tarp or unheated observatory) ???
As you recall, I designed my own heater
control, based around a Humidistat, with its “dialled-in PERCENTAGE
humidity level sensing”. So, I have total control on how
much and how long, the telescope sits soaking wet, when not in
use.
Ref. the Forum FILES section:
“An
- Un-Dewer - Keeping Dome and Scope Dry.pdf “.
A
home-made $60 device to Control dew formation inside the Dome or under the
telescope Tarp
For almost a decade now, I have kept the
BROAN humidistat, around which I designed my environmental dew control,
set at an ... Arbitrary 60% RH.
The cycled 900 watt heater, (I chose), keeps
everything, mirrors, lenses, and electronics, and my (previous AP-900 and
now AP-1200) mount itself, perfectly dry under the nylon tarp’s air
bubble, in all seasons, and any storms. The BROAN controller cycles ANY
chosen AC-powered heating device, within its deadband operation of about
plus/minus 10% RH, so that the heater gets some “hourly respite” (sometimes
shorter on frigid –20 deg.C nights). from otherwise continual heating .
No need to keep the backyard cozy,
when it is under a foot of snow ! :-)
It quickly dries up a soaking wet
telescope system after “tarping” everything, then restarting my Un-Dewer. Of
course, I switch it off during actual telescope use, since I have an LED
bulb on its controlled AC-power section, lighting up the tarp to monitor it from
the house, when it is actually heat-cycling.
Even though it rarely, if ever, turns
on during the day, and cycles itself on for about 20 minutes of an hour under
worst weather & outdoor temperature conditions ...
I wonder WHAT the IDEAL
& SAFE Relative Humidity Level should be for optical mirror and lens
coatings ???
Perhaps keeping the tarped scope at an
average 60% RH (peaking upto about 70% to 72%, before cycling itself off),
may even be overkill.
So knowing the best RH setting, would maintain the quality of
optics and electronics, and still save more energy from being needlessly wasted,
year round.
Thanks for your thoughts on this topic,
Rolando,
Joe Z.
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