[BAA Comets] C/2019 Y4 (ATLAS) debris tail on 2020 April 13

[Richard Miles]

Imaged last night during gusty wind so many images were motion blurred and 
so were discarded.

The main nucleus shines brightly but the debris tail appears to have faded 
significantly. There appears to be a lot of detail downstream from the 
nucleus, so I have processed the longest continuous run of 15 images to show 
what stars are in the vicinity, alongside a Digital Sky Survey image. It 
turns out that only four stars are in the immediate vicinity of the tail and 
so structure seen in the 56 x 20s stack cannot be attributed to the presence 
of faint trailed stars.

The condensation closest to the nucleus is possibly a single longer-lived 
object. Further along the tail is an elliptical bright region that has no 
distinct form. Between these two can be seen two faint accumulations of 
material. Finally, there may be two other faint condensations, both about 8" 
from the centre of the brighter elliptical region in p.a. 95 deg and p.a. 
150 deg. Note these position angles are corrected for the 10 deg 
anticlockwise rotation of my CCD camera relative to the celestial equator.

Richard Miles
Golden Hill Obs., Dorset, UK
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