Far out of your yard telescope, skilled observatories have other ways of stopping dew from affecting astronomical observations.
Skilled observatories such because the Seen and Infrared Survey Telescope for Astronomy in Chile use totally different strategies than amateurs with smaller scopes do to guard their gear. Credit score: G. Hüdepohl (atacamaphoto.com)/ESO
As with beginner scopes, dew is a doubtlessly dangerous drawback at skilled observatories as a result of the water that accumulates on optical surfaces can intrude with the telescope’s efficiency, and it could go away a residue that’s tough to take away as soon as the water evaporates. Cleansing these surfaces continuously could be each costly and impractical.
{Most professional} devices use giant mirrors and wouldn’t have corrector plates like these we discover on Schmidt-Cassegrain telescopes. As a result of space of a giant mirror’s floor (and the mirror’s mass), the quantity of warmth required to keep away from the condensation of water would elevate the mirror’s temperature, distort the incoming gentle, and damage the standard of any knowledge gathered.
Novice astronomers additionally are sometimes shocked by the quantity of dust on the optical surfaces at skilled observatories. Whereas this dust doesn’t intrude with the observations, a dust particle can act as a nucleus for water to condense round and make a large number. Thus, most giant observatories keep away from dew by both closing the observatory effectively earlier than a dew occasion is imminent or by air-conditioning the ability so the temperature stays the identical as that outdoors.
A telescope operator acts as a steward for the ability and decides whether or not to open or shut an observatory primarily based on circumstances equivalent to excessive humidity, excessive winds, lightning, and particulates within the air. Typically this determination goes in opposition to a visiting astronomer’s needs (and thus, attention-grabbing conversations can comply with). However the gear is pricey, so erring on the facet of warning is the standard coverage.
Astronomers additionally construct skilled observatories at excessive and dry areas atop mountains. Humidity ranges that exceed 80 % at these areas normally accompany poor observing circumstances (particularly clouds) that warrant closing the ability anyway as a result of knowledge gathered could be of poor high quality. In mountainous areas, storms can develop rapidly throughout excessive humidity.
Adam Block
Mount Lemmon SkyCenter, College of Arizona
(February 2017 problem)
