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Minchukur weather station
Longitude: 66° 53' 47''
Latitude: 38° 40' 22''
Altitude: 2593 m
Phone: +998 95 5050683
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Phone: +998 95 1423358
Phone: +998 95 1773116
Host institution: UBAI
33 Astronomicheskaya str.,
Tashkent, 100052, Uzbekistan
Phone: +998 71 2358102
Fax: +998 71 2344867
Maidanak observatory (longitude 66°56' E, latitude 38°41' N) is located at the south-east of the Republic of Uzbekistan at a distance of about 500 km from Tashkent and 120 km south of famous historical city of Samarkand. (read more ...)

It lies on the spurs of the Pamir and Alai mountain system at 2600m above sea level. Mount Maidanak was selected for astronomical observations in the late 60-s as a result of a ten-year long site assessment campaign organized at the Ulugh Beg Astronomical Institute (UBAI) of the Uzbekistan Academy of Sciences.

In the early 70-s, when the high-quality atmospheric conditions of Mt. Maidanak have been established, the summit was occupied by Soviet Satellite Laser Ranging (SLR) station. Nevertheless, UBAI astronomers were allowed to continue astronomical observations with two 60-cm and one 48-cm telescopes in the neighborhood of SLR station. Meanwhile Sternberg Astronomical Institute of the Moscow State University (MSU) and a few other Soviet Union institutions had erected their astronomical facilities at a neighboring summit situated 5 km to the west of Mt. Maidanak. So, there are actually two “Maidanak” summits - the Eastern, hosting SLR station and UBAI Observatory, and the Western, hosting all other observatories. By the early 90-s about 10 telescopes as well as the corresponding observatory infrastructure (roads, buildings, mechanical shops, etc.) were equipping the Western summit. By 2011 three telescopes of UBAI were dismounted from Eastern summit. At present all astronomical facilities situated at the Western summit. Hereafter we call “Maidanak Observatory" the Western summit where all civil astronomical facilities had been installed.

MAO operates in the framework of scientific agreements between UBAI and Russian, Ukrainian, US, German, French, Italian, Japanese, Korean, Taiwan and other astronomical institutions. At 2009 Maidanak Users community was established during the first (inaugural) meeting of the Maidanak observatory users in Seoul, Korea.

Clear time
The amount of clear night time hours and its distribution over the seasons for Mt. Maidanak is typical of Central Asian mountains. It is about 58% of available yearly dark time. In absolute units it corresponds to 2000 hours. But unlike Paranal where the seasonal variations of the available clear time are small, the summer observing capacity of Mt. Maidanak is two times higher than in winter (about 90% in July and up to 50% in February). These conditions appear very similar to La Silla, where the same 58% of yearly clear time has a maximum during the southern winter months, i.e. opposite to Maidanak. (read more ...)
Fig.1 Monthly average fraction of clear nights at Maidanak (full line) compared to the statistics of photometric nights at La Silla (dashed line) and Paranal (dotted line). The yearly percentages for each site are respectively 58, 59 and 78% of available dark time.
A survey of the main parameter of atmospheric turbulence (seeing) was carried out at Mt. Maidanak since 1996 with the DIMM (Differential Image Motion Monitor), also used for site testing at ESO observatories of La Silla and Paranal in Chile. The last point allows us to characterize seeing conditions of Mt. Maidanak with an instrument calibrated at ESO observatories. From the whole data span, the mean value of seeing is 0.67 arcsec, the median is 0.69 arcsec. The best monthly median seeing, 0.62 arcsec, was observed in November. A median seeing at Mt. Maidanak appears to be better than at La Silla and as good as at Paranal and Roque de los Muchachos observatories. (read more ...)
Fig.2 Statistical distribution of the seeing at Maidanak: comparison with ESO observatories of La Silla and Paranal and Roque de los Muchachos Observatory at La Palma.

Atmospheric conditions for high angular resolution observations
In July 1998, a site testing campaign for the estimation of atmospheric parameters related to high angular resolution astronomical techniques was organized at Mt. Maidanak, by the common efforts of University of Nice, ESO, Sternberg Astronomical Institute and UBAI. During 9 nights the median wavefront outer scale L0 = 25.9 m and the median isoplanatic angle _0 = 2.48 arcsec were measured with GSM. The corresponding median values of those parameters for La Silla, 25 m and 1.26 arcsec, Paranal, 22.0 m and 1.90 arcsec and Cerro Pachon, 36 m and 2.8 arcsec, confirm the suitability of Mt. Maidanak for high resolution observations. A specific feature of the atmosphere above Mt. Maidanak is a very low speed of wavefront motion. The wavefront coherence time, estimated from GSM measurements, appears to be 12 ms, much larger than for Chilean observatories. (read more ...)
Fig.3 The histograms of the outer scale (top) and
isoplanatic angle (bottom) estimations made with GSM instrument at Mt. Maidanak.
Comparison of all these atmospheric parameters at Maidanak observatory with ones at other well known observatories shows that Mt. Maidanak is a favorable site for installation of large-size telescopes in future. Exceptional features of Mt. Maidanak are very low wind speed and geographical location at middistance between international astronomical facilities at Canaries and Hawaii.

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For more details see: Sh.Ehgamberdiev et al. Astron. Astrophys. Suppl. Ser. 145, 293{304 (2000)
The atmospheric turbulence and meteorology of the Maidanak Observatory in Uzbekistan are reviewed. Night time seeing was measured during the period August 1996 - November 1999 with the ESO Di erential Image Motion Monitor. The median zenith seeing (FWHM) for the entire period of observations is 0.69'' at 0.5 µm. A maximum clear sky season for Maidanak is July - September, with about 90% of possible clear time and a median seeing of 0.69''. The best monthly median seeing, 0.62'', is observed in November. The winter maximum of clear time is usually observed in February (up to 50%) with a FWHM of 0.77''. During an additional site testing campaign (9 nights) organized in July 1998, the median wavefront outer scale L0 of 25.9 m and a median isoplanatic angle θ0 of 2.48'' were measured with the Generalized Seeing Monitor developed at the University of Nice. The temporal evolution of the wavefront can be described by several layers moving at slow velocities with predominant direction from theWest. This corresponds to a remarkably large atmospheric time constant. No correlation between wavefront velocity and the wind velocity at ground level was found. The good seeing, large isoplanatic angle and, especially, slow wind, place Maidanak Observatory among the best international astronomical sites for high angular resolution observations by interferometry and adaptive optics.
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