Cetus III
Cetus lll is an ultra-faint dwarf galaxy that is a satellite galaxy to the Milky Way. It is located at a distance of 251 kiloparsecs in the constellation of Cetus. It has a half-light radius of 90 parsecs.
It was identified as a statistically significant overdensity of stars by the Subaru/Hyper Suprime-Cam Survey. Its small size made it invisible to the Sloan Digital Sky Survey.