C/2017 T3 ATLAS
 

Closest to Sun 2018 July 19 at 0.82AU
Closest to Earth 2018 Aug 1 at 1.35AU
Maximum Magnitude 9 in July 2018
Period approx. 44,000 years


This long period comet had a poor apparition and was never very well situated, remaining close to the Sun throughout.
Despite this, southerners had the best view of perihelion passage.
It was recovered by me on 2018 June 20 as it emerged from morning twilight, trekking southwards through Orion, Monoceros and Canis Major,
remaining relatively low to the horizon.

Below: C/2017 T3 ATLAS. 2018 June 20 at 20:22UT.
Solar elongation = 21 degrees. Comet altitude = 6 degrees. Large aperture photometry approx V mag = 9.5


C/2017 T3 ATLAS (real comet at lower right) and M78 (false comet at upper left) in Orion.
2018 July 9th at 18UT. M78 is listed at magnitude 8.0, comet appears magnitude 9.5.


2018 July 16.82 UT; m1= 9.0, Dia=2, DC=6...25x100mm B [Michael Mattiazzo, Swan Hill, Vic, Australia]
[First visual observation. Moderately condensed but small coma that enhances slightly using a Swan band filter]
 

By mid-August, the comet reached solar conjunction, well south of the Sun, and was then observable in the evening sky, fading from magnitude 10.
Below: C/2017 T3 ATLAS now creeping up into the evening sky.
2018 Aug 18 at 09UT. Approximate magnitude = 10.5. The fuzzy spot to lower right of the comet is NGC3137