May 10
Three Suns in One Frame
Sun Position
The Sun is in Taurus at about +17.9° declination. In the Northern Hemisphere, twilight now extends well past 9 PM at mid-latitudes. Southern Hemisphere observers are approaching their longest nights of the year.
Sky Highlight
The Virgo Galaxy Cluster culminates near midnight this week, offering some of the year's best views of the nearest large galaxy cluster. Its core, roughly centered on M87, contains more than 1,300 confirmed member galaxies. On a transparent night with a modest telescope, scanning through this region produces galaxy after galaxy in quick succession.
Deep Sky Object
M94 (NGC 4736), spiral galaxy in Canes Venatici, about 16 million light-years away. It has an unusually bright, compact nucleus surrounded by a faint outer ring of active star formation, making it a useful example of different modes of stellar birth within a single galaxy. A fairly high surface brightness makes it one of the easier spring galaxies to find. Best from northern and equatorial latitudes.
Featured Star
Zaniah (η Virginis) is a white triple-star system 265 light-years away, spectral class A2V + A2V + A8V. The inner two components orbit each other in about 72 hours (a tight, fast binary) while a third star orbits further out. To the eye it appears as a single steady point, which makes the complexity of what is actually there a useful reminder about how deceiving single points of light can be.
Around This Date
- May 10, 1930Clyde Tombaugh, the discoverer of Pluto, published his first formal report on the new planet in Popular Astronomy, following the announcement made earlier that spring.
- May 11, 1916Albert Einstein presented his complete general theory of relativity to the Prussian Academy of Sciences in its final form, a framework that would transform how astronomers model gravity and spacetime.
Three stars in a 72-hour orbit: time measured differently out there.