Visibility III / V
Comet C/2019 Y4 (ATLAS) is now 1,05au from earth and 1,50au from sun and brightening all the time.
Image 1) Astrodon G filter showing 8' diameter coma and 5' tail towards PA 120°, exposure time 10 minutes.
Image 2) Astrodon R filter showing 2' diameter coma and 4' dust tail towards PA 120°, exposure time 15 minutes.
Image 3) Astrodon B filter showing 4' diameter coma and 8' tail towards PA 120°, exposure time 10 minutes.
Image 4) Semrock CN 387nm narrowband filter showing cyanogen 3883Å gas coma about 18' diameter and dim tail towards PA 120°. Exposure time 60 minutes. Cyanogen gas coma visible here is almost ~800.000 km in diameter.
Image 5) Image 4 processed with CometCIEF showing tail 4' towards PA 120° which is scattered sun light from dust tail particles visible in R filter image. Towards PA 20°-40° is some cyanogen morphology visible but SN is too low. (CometCIEF Samarasinha, N. H., Martin, M. P., Larson, S. M, 2013. Cometary Coma Image Enhancement Facility, http://www.psi.edu/research/cometimen )