Monitoring night-time cloud cover at the Muztagh-ata site

For optical astronomical observatories, the cloud protection throughout night-time straight determines the obtainable observing time (AOT) of a telescope, essentially the most primary parameter in astronomical observations.

Utilizing the ground-based all-sky cloud digicam to watch cloud quantity is the elemental step for astronomical statement web site choice. For the reason that starting of web site testing in January 2017, the ground-based cloud detection has been carried out on the Muztagh-ata web site.

Xu Jing, a senior engineer from Xinjiang Astronomical Observatory of the Chinese language Academy of Sciences, and his collaborators have processed and analyzed the night-time ground-based cloud detection information collected on the Muztagh-ata web site from 2017 to 2021. The outcomes confirmed that the location may present 175 clear nights in a yr, by which 169 nights are with no less than 4 hours of steady observing time.

The examine was printed in Analysis in Astronomy and Astrophysics.

Statistical outcomes of processed photographs confirmed 65% annual obtainable observing night-time, 66% observing night-time with AOT greater than 50%, and 51% of clear nights with AOT greater than 75%. The quantity of steady observing time greater than six hours throughout the night time accounted for 31.1% of the total night-time.

Furthermore, the researchers discovered discrepancies between the CM SAF cLoud, Albedo and floor RAdiation (CLARA) information and ground-based statistical results within the months with common cloud high heights decrease than 3,500m from the bottom. This is perhaps brought on by the limitation of the aptitude of ground-based all-sky cameras to acknowledge excessive clouds.

In response to the researchers, these outcomes may very well be utilized to a variety of cloud protection analyzes.