Comet C/2017 O1 (ASASSN1)

Discovered by the All-Sky Automated Survey for Supernovae (ASASSN) on 19th July, 2017, Comet C/2017 O1 was shining at magnitude 15 in Cetus. The comet has taken everyone by surprise when it brightened a staggering hundred times to magnitude +10. Now readily visible in backyard telescopes or decent sized binoculars from the southern hemisphere, the comet is expected to continue to brighten and move to the northern hemisphere from September through October.

As the name might suggest, ASASSN is a survey for discovering supernovae, these surveys are prone to discovering other objects in the night sky. This is the first comet discovery by the survey. 

At the time of writing the comet resides in Eridanus and should then climb in to Taurus and Perseus in the coming weeks to greet northern hemisphere observers where it will then reside in a very favourable position for observation. The comet is expected to reach perihelion on 14th October at 1.5 AU from the Sun (just outside the orbit of Mars). 

Current Magnitude (Estimated): 8.5 

Comet ASASSN1 Finder Charts

27 July – 03 September (Southern Hemisphere)

C/2017 O2 ASAS-SN Finder Chart  C/2017 O2 ASAS-SN Finder Chart
Click images to enlarge

03 September – 25 October (Northern Hemisphere)

C/2017 O2 ASAS-SN Finder Chart  C/2017 O2 ASAS-SN Finder Chart
Click images to enlarge

Comet C/2017 O2 ASAS-SN Live Position Data