- www.kevin-palmer.com - I'm still sorting through pictures from the Geminid meteor shower, but I wanted to post this picture from early this morning. Comet 46P/Wirtanen flew by the Pleiades in the constellation Taurus. Also known as the Seven Sisters, this star cluster is one of the closest to Earth at a distance of about 444 light years away. The extra hot and luminous stars cast their light on the nearby reflection nebula, which gives it the blue color. Comet 46P/Wirtanen was at it's closest approach just 7.2 million miles (11.5 million km) away from Earth. This makes it one of the top 10 closest comet encounters of the Space Age. While they look the same size in this image, the comet is quite a bit fainter, just barely detectable to the naked eye. The nucleus of the comet is less than 1 mile wide, but it's diffuse coma (cometary atmosphere) is larger than the planet Jupiter.
This image was shot with a Nikon 180mm f2.8 lens on a Nikon D750. It is a stack of 8 2.5 minute exposures, along with 4 dark and bias frames. An iOptron Skytracker was used to track the stars. I'm going to need a new tracker soon though. After shooting images for 1 hour, I had to delete 2/3 of them due to tracking errors.