Comet C/2009 F6 (Yi–SWAN) is a non-periodic comet which appeared in March 2009.

It was first discovered by Korean amateur astronomer Dae-am Yi on March 26, 2009, using a Canon 5D camera and 90-mm lens. It is believed to be the first comet discovered by a Korean in the modern age.(2) Independently, on April 4 Rob Matson reported he had discovered a comet in the SWAN instrument photographs on the SOHO (Solar and Heliospheric Observatory) spacecraft website.(3)

The comet was not bright enough to be seen by the naked eye, but was theoretically visible through amateur telescopes. However, it was harder to see than predicted, as it remained quite small and did not form much of a visible tail. It reached a peak magnitude around +8.5 in April into May, and passed 1.5 degrees south of the Double cluster in Perseus on April 23