May 29 – Discovery of M10, 1764

The globular cluster Messier 10, discovered by Charles Messier, unsurprisingly, was described by him as a “nebulous patch without stars” on May 29th, 1764, after which he could relax and ignore it, safe in the knowledge that it was not a comet, and therefore unworthy of further attention.  M10, also known as NCG 6254, is in the large, equatorial constellation of Ophiuchus, “the serpent bearer”, and is about 80 light years across, meaning it should occupy an area of the sky two-thirds that of the full Moon.  This sounds impressive, but if you find it in the average telescope it won’t look anything like that big, because you will only be able to see the core.

Messier 10 (Image credit: NASA / STScI / ESA)

This beautiful photograph was taken by the Hubble Space Telescope, and shows the core of M10, at a distance of about 15,000 light years.


Yet another asteroid day.  Today we have 72 Feronia, discovered on May 29 1861 by the German-American astronomer Christian Heinrich Friedrich Peters, who went on to find another 47, so he must deserve a birthday shout-out on September 19.

Feronia is a large, dark main belt asteroid, about which there isn’t much to say except that it has a diameter of about 86km, a rotation period of a little more than 8 hours, and takes over 3 years to orbit the Sun.

Feronia’s namesake is a Roman goddess, variously associated with fertility, health and wildlife. She was apparently very popular among plebeians, and as I’m one myself I must remember to tweet her feast day on November 13.

Marble head, suspected to be that of Feronia (Museo Civico Rieti, Italy).

1889  –  Discovery of asteroid 284 Amalia  by Auguste Charlois.


Updated: May 2019.