July 1
The Scorpion at Its Zenith
Sun Position
The Sun sits in Gemini, declining toward Cancer, at roughly +23° declination. Northern Hemisphere days are long and midsummer warm; Southern Hemisphere observers are in midwinter, with shorter days and Scorpius riding high overhead in the south.
Sky Highlight
Earth reaches aphelion on or very near July 4 each year, its farthest point from the Sun, about 152.1 million km. On July 1 the planet is within a day or two of that far point, a counterintuitive moment: Northern Hemisphere summer peaks when Earth is actually slightly farther from the Sun than average. No hemisphere difference applies to aphelion itself.
Deep Sky Object
M4 (NGC 6121), a globular cluster in Scorpius, roughly 7,200 light-years away. It is one of the closest globular clusters to Earth and one of the few in which individual stars can be resolved with a modest amateur telescope; its core is unusually loose and elongated. Best seen from the Southern Hemisphere or low northern latitudes where Scorpius climbs high, but visible across mid-northern skies on clear nights.
Featured Star
Antares (α Sco) is a red supergiant about 550 light-years away, classified M1.5Iab-b, a cool, luminous giant so large it would engulf Mars's orbit if placed at the center of our solar system. It burns at the heart of Scorpius, visible as a distinctly ruddy point even to the naked eye.
Around This Date
- July 1, 1917The 100-inch Hooker Telescope mirror blank arrived at Mount Wilson Observatory, beginning a multi-year installation process that would make it the world's largest telescope by 1919.
- July 4, 1054Chinese astronomers recorded a 'guest star' in Taurus bright enough to be seen in daylight, the supernova whose remnant is now the Crab Nebula (M1).
Antares has been burning its fuel at a furious rate for millions of years; on any given night you are watching a star that is already late.