Visibility I / V
Comet C/2021 A2 (NEOWISE) is now much dimmer than I last observed it at February 16th. In this 115min exposure using 387nm narrowband filter cyanogen CN 3883Å radical gas coma diameter is 0,6'/40.000km and wide fan-shaped cyanogen gas tail length 1'/60.000km towards PA 330° is visible. Comet current distance from sun is 1,62au and from earth 1,43au. I took also R channel photometric image and although the image had poor S/N I measured comet R channel brightness as 16,3mag. CN channel brightness measurement is difficult because lack of 3883Å reference stars, not very scientific but when using B channel reference stars I measured comet CN coma roughly brightness as 15,1mag.