An Estimate of Transformation Coefficients for The V Magnitude of No.1 CCD System at Yunnan Observatory

In the quick way to determine transformation coefficients, we estimated transformation coefficients for the V magnitude of No. 1 CCD system at Yunnan Observatory. The results, A=-0.388 and A=3.734 (1 second of exposing light time), show that deviation of the CCD system from the UBV system is very serious. However, if high precision is not demanded, the transformation to the UBV system can be carried out.By the observational data for the Halley comet on November 5, 1984, we estimated that its magnitude in the V band was 21.22 mag.