Comet P/2017 S5 was discovered on CCD exposures taken on 2017 Sept. 27.5 UT
with the ATLAS 0.5-m f/2.0 Schmidt telescope at Haleakala in the course of
the "Asteroid Terrestrial-impact Last Alert System" (ATLAS) search program.
In reporting the discovery, Aren Heinze noted that that the object showed
clear cometary features with a tail about 20" long toward position angle
approximately 235 degrees, adding that the head of the comet also seemed
elongated in the corresponding northeast-southwest direction.
Pre-discovery ATLAS observations were subsequently identified from
four additional nights between Sept. 11 and 23.
The discovery details were announced on