Investigating the Efficiency of the Beijing Faint Object Spectrograph and Camera (BFOSC) of the Xinglong 2.16-m Reflector

TL;DR

This study systematically measures the total efficiency of the BFOSC instrument on the Xinglong 2.16-m telescope, providing valuable data for observers and technicians to optimize observational strategies and improve instrument performance.

Contribution

It offers the first comprehensive efficiency measurements of BFOSC across various configurations, aiding in better instrument utilization and technical enhancements.

Findings

Efficiency varies with different grisms and slit widths.

Results assist observers in selecting optimal slit widths for their goals.

Data helps technicians identify factors affecting efficiency and improve performance.

Abstract

The Beijing Faint Object Spectrograph and Camera (BFOSC) is one of the most important instruments of the 2.16-m telescope of the Xinglong Observatory. Every year there are ~ 20 SCI-papers published based on the observational data of this telescope. In this work, we have systemically measured the total efficiency of the BFOSC of the 2.16-m reflector, based on the observations of two ESO flux standard stars. We have obtained the total efficiencies of the BFOSC instrument of different grisms with various slit widths in almost all ranges, and analysed the factors which effect the efficiency of telescope and spectrograph. For the astronomical observers, the result will be useful for them to select a suitable slit width, depending on their scientific goals and weather conditions during the observation; For the technicians, the result will help them systemically find out the real efficiency of telescope and spectrograph, and further to improve the total efficiency and observing capacity of the telescope technically.