June 3
The Preceding One
Sun Position
The Sun is in Gemini, declination around +22°. Northern summer approaches; southern skies enjoy their longest nights.
Sky Highlight
No major meteor shower peaks today. The center of the Milky Way is well-placed for southern observers in June evenings; from mid-northern latitudes the galactic core rises late but is increasingly accessible through the month.
Deep Sky Object
M10 (NGC 6254), a globular cluster about 14,300 light-years away. M10 in Ophiuchus is a large, loose globular cluster that resolves readily into individual stars, forming a matched pair with nearby M12, the two are separated by only about 3° on the sky. Well-placed for both hemispheres through June and July evenings; a binocular object, resolved at low telescope magnification.
Featured Star
Sabik (η Oph) is a white main-sequence pair (A2V + A3V) about 88 light-years away, sitting in the body of Ophiuchus; its Arabic name means 'the preceding one.' Two nearly equal white stars orbiting together, their combined light steady and cool against the summer sky.
Around This Date
- June 3, 1769James Cook and his crew observed the Transit of Venus from Fort Venus on Tahiti, recording the event to help calculate the astronomical unit, the Earth-Sun distance.
- June 1, 1990The Hubble Space Telescope returned its first images, which revealed a serious spherical aberration in the primary mirror that would require a corrective optics mission.
Even a twin star carries one name, and this one means simply: the one that came before.