July 11
The Twin White Pair
Sun Position
The Sun is in Cancer at roughly +21.1° declination. Northern Hemisphere evenings are warm and long; Southern Hemisphere winter deepens, with Ophiuchus visible from mid-southern latitudes along the northern horizon.
Sky Highlight
No named meteor shower peaks on July 11. Ophiuchus culminates near the meridian at midnight for mid-latitude observers this month, making its globular clusters accessible. The constellation's low declination makes it visible from both hemispheres, though Southern Hemisphere observers see it higher in the sky.
Deep Sky Object
M12 (NGC 6218), a globular cluster in Ophiuchus roughly 15,700 light-years away. Slightly smaller and less concentrated than its near neighbor M10, M12 resolves well in medium telescopes and is accessible to both hemispheres. It lies close to the celestial equator.
Featured Star
Sabik (η Oph) is a binary star about 88 light-years away in Ophiuchus, consisting of two nearly identical white main-sequence stars (A2V and A3V) orbiting each other with a period of about 88 years. The name 'Sabik' derives from an Arabic phrase meaning 'the preceding one,' though its exact original application is uncertain.
Around This Date
- July 11, 1979The Skylab space station reentered Earth's atmosphere after years in orbit, scattering debris across the Indian Ocean and southwestern Australia, marking the end of NASA's first space station program.
- July 13, 1995Comet Hale-Bopp was independently discovered on this date by Alan Hale and Thomas Bopp, more than a year before its 1997 perihelion passage when it became one of the brightest comets of the 20th century.
Two stars nearly identical in mass and temperature, circling each other for 88 years. Sabik is a binary system that astronomy nearly invented for the classroom.