June 20
Vega at Midsummer
Sun Position
The Sun is in Gemini, declination near +23.4°. The Northern Hemisphere's summer solstice falls on June 20 or 21 in most years, today may itself be the solstice, the moment the Sun reaches its northernmost point on the ecliptic. Longest day north, shortest day south.
Sky Highlight
The June solstice, the Sun at its northernmost declination (+23.4°), directly overhead at the Tropic of Cancer. The Northern Hemisphere's longest day; in the Southern Hemisphere, the shortest. The solstice falls on June 20 or 21 depending on the year. No planetary event, but the date itself is the year's northern hinge.
Deep Sky Object
M57 (Ring Nebula), a planetary nebula about 2,300 light-years away. M57 in Lyra is the most recognizable planetary nebula in the sky, a glowing smoke ring from a star that shed its outer layers roughly 6,000 to 8,000 years ago; the hot white dwarf at its center is visible in medium to large amateur telescopes. Excellent from northern latitudes through summer; also visible from southern mid-latitudes, though lower in the sky.
Featured Star
Vega (α Lyr) is a main-sequence A-type star (A0Va) just 25 light-years away, close enough that it was the first star ever photographed, in 1850, and the first to have its spectrum recorded. It will be our north pole star in about 12,000 years, when precession brings the celestial pole back toward it.
Around This Date
- June 20, 1850Vega became the first star other than the Sun to be successfully photographed, using a daguerreotype at the Harvard College Observatory, a 100-second exposure through a 15-inch refractor.
- June 20, 1944The German V-2 rocket MW 18014 reached an altitude of 176 kilometers during a test launch, becoming the first man-made object to cross the boundary of space.
On the day the Sun turns back, Vega rises in the northeast, bright, close, and already well on its way to becoming a pole star.