Report on seeing, sky brightness, and meteorological properties measurements at Timau National Observatory site

Abstract

With the existence of the Timau National Observatory, the site testing of the observatory location must be carried out to provide supporting data regarding the quality of the National Observatory site. Some site testing that needs to be done are seeing, sky brightness, and meteorological properties measurements. In this paper, the seeing and sky brightness measurements in July-August 2021 are presented. These measurements were conducted using the Differential Image Motion Monitor (DIMM) method with a 20 cm telescope and a Sky Quality Meter (SQM) respectively. From the results of these measurements, it was found that the site of Timau National Observatory has good seeing conditions with median of 0.92 arcseconds and most sky brightness values are around 22.02 magnitude per square arcsecond. The monitoring results of meteorological properties, such as air temperature, barometric pressure, relative humidity, and wind speed and direction during August 2021 that recorded by an automatic weather station are also presented.