Comet Leonard

C/2021 A1 (Leonard) is a long period comet that was discovered by G. J. Leonard at the Mount Lemmon Observatory on 3 January 2021 (a year before perihelion) when the comet was 5 AU (750 million km) from the Sun. It had a retrograde orbit. The nucleus was about 1 km (0.6 mi) across. It came within 4 million km (2.5 million mi) of Venus, the closest-known cometary approach to Venus.

In early December 2021 the comet had an apparent magnitude (coma+nucleus) of around 6. The first reports of naked-eye observations by experienced observers started coming in on 5 December 2021. Much like observing Messier 33, the low surface brightness of the comet can make it difficult to observe near urban areas. On 3 December 2021 many emission lines of NH2, C2, and [OI] were detected in the spectrum of the comet in the wavelength range between 5000 and 7000 Å. On the morning of 6 December 2021 the comet was about 5 degrees from the star Arcturus. On 14 December 2021 the comet was 14.7 degrees from the Sun and quickly became better seen from the southern hemisphere.

(source: Wikipedia)