Discovery
Comet C/2017 S2 was discovered on four w-band Pan-STARRS1 CCD images
taken with the 1.8-m Pan-STARRS1 telescope at Haleakala (Hawaii, USA) on Sept. 16 UT
and reported by Eva Lilly (Institute for Astronomy, University of Hawaii).
The discovery observations showed evidence for a
faint tail 4" long toward the west, but the head appeared essentially
stellar.
The discovery details were announced on
CBET 4431.