An Automatic CCD Observation System Based on the ASCOM Standard

Efficiencies of astronomical observations largely depend on the degree of automation. The CCD system of the 2.4m telescope of the Yunnan Observatory did not have an automatically controllable filter wheel. To improve the efficiency of the telescope, we have developed a filter-wheel control system based on the ASCOM standard. The CCD camera and filter wheel are controlled by a MaxIm DL software, making automatic CCD observation possible. The system has been applied to the 2.4 meter telescope since early 2009. Practical application results show that it functions properly and reliably, it meets the requirements of automatic CCD observation, and achieves the goal of improving the efficiency of astronomical observation. Although the mainstream operating system for astronomical instrumentation is Linux, a Windows platform is also a low cost and effective automation solution for the several reasons. First, an ASCOM driver is very easy to develop because there are useful templates and examples. Second, the MaxIm DL software is a mature commercial software with powerful functions for CCD control and it supports the ASCOM standard. These make it convenient to incorporate in the software utilities for various astronomical instruments. The paper finally discusses the principle of ASCOM filter-wheel driver and its control method based on the MaxIm DL software. It also provides some empirical references for the ASCOM standard and MaxIm DL software in astronomical applications.