Estimating Seeing Values From Various Refractive Index Structure Parameter Models at Maunakea, Hawaii Bayu Septiadi (a*), Anton Timur Jaelani (b,c,d)
a) Astronomy Master Program, FMIPA, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia.
b) Astronomy Research Group and Bosscha Observatory, FMIPA, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia.
c) U-CoE AI-VLB, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia.
d) University Center of Excellence for Space Science, Technology and Innovation, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia.
Abstract
Astronomical seeing is the disturbance of astronomical images due to atmospheric turbulence, which affects the quality of astronomical observations through telescopes. Evaluation of seeing conditions is important in observatory site selection, but observations are in situ and limited to certain areas. This study utilizes ERA5 reanalysis data in the form of wind speed at various atmospheric layers (110.9 m to 32,400 m) to model seeing indirectly. By applying the Hufnagel-Valley model, the wind speed profiles are converted into the structure of atmospheric refractive index (C_n^2) and Fried parameter (r_0), which represent the magnitude of seeing. The analysis results show that wind speed variations between atmospheric layers have a significant correlation to the degradation of seeing quality. This approach has the potential to be an alternative method in identifying ideal observatory locations based on global atmospheric data.
