March 18
Foot of the Cross
Sun Position
The Sun is in Pisces at roughly +16° declination; the equinox is imminent, and from the equator the Sun is nearly directly overhead at noon, hemispheric parity is just days away.
Sky Highlight
The Southern Cross (Crux) is rising in the southeastern sky for southern observers in the March evenings, becoming increasingly well-placed through April. From latitudes below about +25°, Acrux clears the horizon by mid-evening in March and is surrounded by some of the densest Milky Way star fields visible from Earth.
Deep Sky Object
NGC 4755 (Jewel Box Cluster), an open cluster in Crux, about 6,400 light-years away, resolved in small telescopes into dozens of blue-white stars punctuated by a single red supergiant; John Herschel named it for the color contrast. Accessible only from latitudes below about +25°.
Featured Star
Acrux (α Cru) is a blue subgiant and blue main-sequence pair 321 light-years away (spectral class B0.5IV + B1V) the brightest star in the Southern Cross and the twelfth brightest in the sky overall. The two components orbit each other over a long period and are embedded in the Milky Way's star-rich southern arm, giving Acrux one of the most visually spectacular backgrounds of any naked-eye star.
Around This Date
- March 18, 1965Cosmonaut Alexei Leonov performed the first spacewalk in history, exiting Voskhod 2 for 12 minutes while his spacesuit ballooned in vacuum, nearly preventing his re-entry.
- March 18, 1990Thieves stole 13 artworks from the Isabella Stewart Gardner Museum in Boston (including works depicting celestial themes) in the largest art theft in history; the pieces remain missing.
The Southern Cross rises into autumn skies, its foot-star embedded in a Milky Way so dense it looks like cloud.