He co-discovered several comets, including C/1968 H1 (Tago-Honda-Yamamoto), C/1969 T1 (Tago-Sato-Kosaka), C/1987 B1 (Nishikawa-Takamizawa-Tago).
At the Satsuki Observatory established in 1996, Tago has supported and encouraged amateur astronomers in Yanahara, Okayama.
2),[1] V574 Pup Archived 2008-09-30 at the Wayback Machine (Nova Puppis 2004), V2467 Cyg Archived 2008-07-04 at the Wayback Machine (Nova Cygni 2007) and V459 Vul Archived 2008-07-20 at the Wayback Machine (Nova Vulpeculae 2007 no.2).
[2] In 2006 he was the first astronomer to discover a micro-lensing system outside the Magellanic Clouds[3] and the bulge of our Milky Way.
A red or a brown dwarf star passed exactly in front of GSC 3656-1328 and the gravity of the dwarf star directed more light to the observers on Earth.