Surface photometry of comet Hale-Bopp carbon images

A very long series of photographic observations of the comet Hale-Bopp has been made during January-April 1997 at the double astrograph (400/2000) of the Main Astronomical Observatory (Kyiv, Ukraine). Some of the cometary photos were obtained with two wide-band filter combinations. One of these combinations isolates C-2 emission, another - the nearby dust continuum. The images were digitized by means of AMDPH-XY machine and then calibrated following the standard procedure. After subtraction of the dust continuum the distribution of surface brightness in the C-2 emission coma of comet Hale-Bopp was studied. We found an asymmetric brightness distribution both pre- and post-perihelion. On 21.77 April 1997 a secondary brightness peak is found at the distance of 1.03 x 10(5) km from the nucleus. It is possible that this peak is related to the extended source of the C-2 molecules.