APOD: 2022 July 21 - Messier 10 and Comet

Good evening, Rallypoint, and welcome to the July 21st Astronomy Picture of the Day (APOD): "Messier 10 and Comet." Messier 10 (aka M10 and NGC 6254) is a globular cluster of stars in the constellation Ophiuchus. Charles Messier discovered M10 on May 29, 1764, and noted it in his catalogue as a 'nebula without stars'. Using larger instrumentation, amateur astronomer Admiral William Henry Smyth (1788-1865) provides a more accurate description: "A rich globular cluster of compressed stars, on the Serpent-holder’s right hip. This noble phenomenon is of a lucid white tint, somewhat attenuated at the margin, and clustering to a blaze in the centre. It is so easily resolvable with very moderate means, that we are surprised at Messier’s remark, on registering it in 1764: ‘A beautiful round nebula. It may be seen, with attention, by a telescope of three feet in length.’"

Comet PanSTARRS was discovered in May 2017 when it was beyond the orbit of Saturn. This image was captured on July 15th, a day after the comet made its closest approach to Earth. PanSTARRS will make its closest approach to the Sun on December 19th.