June 22
The Pyramid Builders' Pole
Sun Position
The Sun is in Cancer (having crossed the solstice point), declination just under +23.4° and now fractionally decreasing. Northern days have passed their peak and are very slowly shortening.
Sky Highlight
No major meteor shower peaks today. The first full night after the solstice carries a subtle shift: the northern sky's slow drift toward autumn has begun, though nights will remain short for weeks. Draco is high overhead from northern mid-latitudes.
Deep Sky Object
NGC 6210, a planetary nebula roughly 6,500 light-years away. NGC 6210 in Hercules is a bright, compact planetary nebula that appears bluish-green in telescopes, with a size small enough to resemble a star at low magnification, it rewards higher power, which reveals its disk. Well-placed from northern latitudes in June and July evenings; also accessible from southern mid-latitudes.
Featured Star
Thuban (α Dra) is a white giant (A0III) about 303 light-years away, not Draco's brightest star, but historically its most important: it served as the pole star around 2700 BCE, during the construction of the Egyptian pyramids, when precession had carried the celestial pole near enough to Thuban for it to be used as a north reference. The shaft of the Great Pyramid at Giza is aligned toward it.
Around This Date
- June 22, 1978James Christy and Robert Harrington at the U.S. Naval Observatory confirmed the discovery of Charon, Pluto's large moon, from photographic plates taken on this date.
- June 24, 1997The Progress M-34 cargo spacecraft collided with the Mir space station during a manual docking test, depressurizing the Spektr module and nearly ending the station's operational life.
Thuban held the pole while the pyramids were being built and has been quietly retiring ever since.