QDaedalus is an automated, computer-controlled astro-geodetic measurement system.
Astronomical deflections of the vertical measured by the QDaedalus system are significantly
influenced by atmospheric refraction. Therefore, the measuring system was further
improved by recording the environmental parameters influencing the refraction (air
pressure, temperature, humidity) with accurate and high time resolution. In addition
to meteorological parameters, refraction also depends on the spectrum of the stars.
Both the continuously measured meteorological parameters and the color of the stars
were taken into account in the calculation of the refraction. To control the method,
we used the deflection of the vertical values of the Pistahegy point in the southern
part of Budapest which were determined over 7 years during 260 night measurements.
The corrected measurements fit within 0.01" with the average value of previous Pistahegy
measurements. The standard deviation of the differences due to the corrections, however,
may reach 0.015" for the DOV components.
