[AZ-Observing] Re: Scope Color
- From: "Workman, Brian \(AZ76\)" <brian.workman@xxxxxxxxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Wed, 28 Feb 2007 08:34:01 -0600
Black is probably best; both because it is less distracting, but also
for thermal reasons. If you really want to split hairs, for optimum
performance, ie the shortest time for the 'scope to reach thermal
equilibrium and minimize the tube currents, it doesn't matter so much
what color it is in visible light, what you want is the paint with the
highest emissivity you can find. Think of it this way, you want the tube
to be as "black" as possible in the thermal infrared region
(~10microns). This way the tube will radiate heat away as quickly as
possible.=20
OK somebody is going to say "but, white will reflect the heat", but
presumeably you are not observing during the day. Even a white scope
will eventually warm up over the day. What you want is to dump that
accumulated heat as rapidly as possible.=20
> -----Original Message-----
> Does anyone have any experience or notice a difference in=20
> observing based on the color of one's telescope tube? I know=20
> white reflects the most amount of light and should therefore=20
> remain cooler as day drops to night, thus probably=20
> eliminating tube currents, but stands out like a sore thumb=20
> at night. Black would be the ideal color for nighttime=20
> observing, but if your were to leave it in the daylight,=20
> inner tube conditions maybe effected for part of the night,=20
> as well as the mirror. And these are both the extremes.
>=20
> Am I just splitting hairs here (obviously not to make cross=20
> hairs), or are there any studies on this? Anyone have=20
> experience in this situation? Ultimately, I am repainting my=20
> ten's aluminum tube and weighing between aesthetics and=20
> functionality. Of course, I could get the best of both=20
> worlds in terms of functionality and paint the tube white and=20
> the focuser area black.
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