The comet C/2020 NEOWISE F3 in the Big Dipper is captured on the picure on the day it was closest to earth. On that day, the 23rd of July at 3:09 CEST the comet was 0.63 astronomical units (about 103.5 million kilometres) away from earth and was the largest on the sky. It had two prominents tails, one which was white, consisting of dust and the other one - blue, which consists of ions. The white tail is bent thanks to the gravitational pull of our Sun, while the blue one is always pointed directly away from the Sun. While it is usually only barely visible by the naked eye, on the picture it is visible at the length equal to 60 full moons next to each other. During the time when it was best observable, the comet was visible over the constellation of „Big Dipper“ (which is a part of the Ursa Major constellation) which made this flyby incredibly photogenic. It was one of the most visible comets since the year 1998 when the Hale-Bopp comet was visible on the night sky. The NEOWISE comet will be visible again in 6 765 years.
Astronomy photo of the Day NASA (APOD) is a prestigious award of the most interesting astronomy photo of the day which is selected and competed by an educational description by a team of editors: prof. Jerry Bonnell (from the Michigan Technological University and prof. Robert Nemiroff (University of Maryland) who both work with NASA. The motto of APOD is „Discover the Cosmos“ and since 1995 when the collection was started it became one of the most respected of its type in the world. The original texts are translated into 23 languages including Czech (translations into which have been done since 1999 by Josef Chlachula) APOD is seen by hundreds of millions of followers on social media every day.