Visibility III / V
Comet C/2019 Y4 (ATLAS) optocenter is strongly oval shaped in all colour channels RGB and UV/CN and there is not point like optocenter visible representing comet's possible disintegration. Moon phase was 95% but fortunately it was low in the sky.
Image 1) Crop of Astrodon R filter (image 3) showing strongly oval shaped optocenter. One fragment can be seen preceding/leading very close optocenter, measured 9" towards PA 290° / "2:30 o'clock"
Image 2) Astrodon G filter showing 7' diameter coma and 11' tail towards PA 95°, exposure time 10 minutes.
Image 3) Astrodon R filter showing 3' diameter coma and 8' dust tail towards PA 95°, exposure time 15 minutes.
Image 4) Astrodon B filter showing 4' diameter coma and 9' tail towards PA 95°, exposure time 10 minutes.
Image 5) CN 387nm narrowband filter showing cyanogen 3883Å gas coma about 9' diameter and dim tail towards PA 95°. Exposure time 25 minutes.
Image 6) Image 5 processed with CometCIEF showing strognly oval shaped optocenter 30" long and wide tail/jet towards PA 95° .