January 10
Bouncing Light Off the Moon
Sun Position
The Sun lies in Capricornus, about 22.1° south of the celestial equator. In the Northern Hemisphere the days are still short but lengthening; in the Southern Hemisphere this is high summer with long, warm evenings.
Sky Highlight
Perseus rides high overhead on northern evenings, its stars threaded through a bright arm of the Milky Way. Lower but visible from northern-tropical southern latitudes.
Deep Sky Object
Messier 34, an open cluster about 1,500 light-years away in Perseus, loose enough to resolve in binoculars. Northern Hemisphere favored.
Featured Star
Mirfak (α Per), a yellow-white supergiant in Perseus, about 592 light-years away. Mirfak, Perseus's elbow, shining at the heart of a young star cluster.
Around This Date
- January 10, 1946The U.S. Army's Project Diana bounced radar signals off the Moon, opening radar astronomy.
- January 9, 1839The French Academy of Sciences announced the daguerreotype, photography's first widely practical process, which would transform observational astronomy by making permanent records of faint objects possible.
We learned the Moon's distance by listening for an echo.