March 19
Debris and Promise
Sun Position
The Sun is in Pisces, declination near +16.5°; the vernal equinox for the Northern Hemisphere is tomorrow, and tonight's sky is nearly perfectly split between day and night across the globe.
Sky Highlight
The vernal equinox falls on March 20 (or occasionally March 19 depending on the year and time zone). On the eve of the equinox, Leo is due south at midnight from mid-northern latitudes (Denebola well-placed in the east of the constellation) and every observer on Earth is experiencing nearly equal day and night.
Deep Sky Object
M65 (NGC 3623), a spiral galaxy in Leo, about 35 million light-years away, slightly more tightly wound than its neighbor M66; they form the Leo Triplet with NGC 3628 and all three are potential targets in a single wide eyepiece field. Visible from both hemispheres in spring.
Featured Star
Denebola (β Leo) returns in Leo's tail, a main-sequence A-type star at 35.9 light-years with spectral class A3Va, and one of the closer debris-disk systems known. The disk around Denebola extends beyond where Neptune sits in our solar system, and its infrared excess was detected by IRAS in 1983, one of the first confirmed circumstellar disks around a young star.
Around This Date
- March 19, 1906Adolf Scheiner, a pioneer in stellar spectrophotography, died; his early work on photographing stellar spectra helped establish the methods that later produced the Harvard spectral classification system.
- March 20, 1916Albert Einstein submitted his final paper on general relativity to the Prussian Academy of Sciences, completing the theoretical framework that would be confirmed by Eddington's 1919 solar eclipse observations.
On the night before equal day and night, the lion's debris-ringed tail rises in the east, the sky balanced, the future material for planets still orbiting.