CN photometry of Comet Levy 1990XX

Pawel Magdziarz, Maciej Winiarski and Waclaw Waniak

Astronomical Observatory, Jagiellonian University, ul. Orla 171, Krakow, Poland

The results of photoelectric photometry with the narrowband CN and C3 interference filters and a set of diaphragms of different radii. Because the dust component of the cometary spectrum was not observed, the flux in the C3 filter was treated as the upper limit for the dust component in the UV part of the spectrum. The raw flux observed in the CN filter makes the upper limit and after subtraction of the C3 flux makes the lower limit for pure CN radical flux. These limits were converted into the CN production rates according to the classical Haser model and the differences between them are smaller than 20%. The dependence of the production rate on heliocentric distance in the range of 1.7-1.3 AU is presented.