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Meteorological and sky conditions at the astro-center AAV Lue-Stailas

Geography
The Val Mustair excels with an average of 250 sunny days and 150 clear nights per year and practically no air pollution. Well protected by the surrounding mountain chains from storms and precipitations, the region has its own mild microclimate that is continental and relatively dry. This is also reflected by the forests of Swiss stone pines and larches growing abundantly on the flanks of the valley. The high altitude of AAV Lue-Stailas situates it generally above most stratus cloud limits.

Coordinates
Latitude: 46° 37.5' N
Longitude: 10° 22.0' E
Elevation: 1935 m (6350 ft)

Climate
Rainfall: ~ 700 mm/yr
Number of sunny days: ~250/yr
Average temperature: 8° Celsius

Weather satellite

(search for Lü)

Lunar phase

AAV will soon provide its own real-time data with an on-site weather and seeing monitor.

Temperature
Our transparent night skies and high altitude can make for pretty chilly nights. Winter night temperatures can drop some times to 10-20°C below zero (14 to -4°F). Nevertheless, the quality and richness of the winter skies make them well worth putting on some extra cloth. Moreover, all domes can be operated remotely from the AAV center as well, which will help you to stay warm. In summer, which starts usually in late June, the night time temperatures range usually in the 10-15°C (50-60°F).

Sky brightness over the domes of AAV Lue-Stailas

The entire valley (over 420000 acres) counts about 1600 inhabitants and there are no large cities within a perimeter of at least 150 miles. The illumination of the small villages in the valley at night is insignificant.

The computed ratio between artificial and natural sky brightness puts AAV Lue-Stailas around classes 2-3 of Bortle's Dark Sky Scale

Numeric models predicting seeing indices in our area (register a free account with myMap Server in Meteoblue and go to "Astronomy Seeing") estimate an average of 2 arcsec (for 8-14-inch telescopes).

.
Categories     Seeing in arc-seconds

V                        < 0.4
  IV                   ~ 0.4-0.9
  III                  ~ 1.0-2.0
   II                   ~ 3.0-4.0
  I                        > 4.0

* AAV Lue-Stailas seeing conditions

Sky visibility
Our skies remain unobstructed down to about 5-15 degrees above the horizon (needs Google Earth). In the north, free skies can be observed down to 25 degrees.