July 2, 2018 - Historic Henrietta

Historic Henrietta   This week marks the 150th birth anniversary of a key yet often overlooked astronomer. Henrietta Swan Leavitt volunteered at the Harvard College Observatory after graduating from college. In 1902, she joined the staff as a “human computer,” studying photographic images of stars to determine their magnitude. During her career, Leavitt studied thousands of variable stars–many of which were located in the nearby Small Magellanic Cloud, shown here. Her most important achievement was discovering the period-luminosity relationship of Cepheid variable stars. Informed by this discovery, Edwin Hubble drastically redefined the size of the Universe. Though relegated to obscurity during her lifetime, Leavitt, who died in 1921, is now increasingly recognized for her work.

Image credit: ESO/VISTA VMC

Weekly Calendar

July 2 - 8, 2018

Holidays - Sky Events - Space History

 

Monday 2

1985: European Space Agency launches Giotto probe to study Halley’s Comet

Tuesday 3

Neptune 3° north of Moon

1935: Harrison Schmitt born

Wednesday 4

Independence Day

1054: Crab Nebula supernova observed
1868: Henrietta Swan Leavitt born
1997: Mars Pathfinder lands on Mars
2005: Deep Impact probe collides with comet Tempel 1
2006: STS-121 Discovery launched
2016: Juno spacecraft begins orbiting Jupiter

Thursday 5

1966: Apollo-Saturn 203 launched
1982: Space Shuttle Challenger arrives at Kennedy Space Center for first time

Friday 6

Last Qtr Moon 3:51 AM ET
Earth at aphelion

1687: Isaac Newton publishes his Principia

Saturday 7

Uranus 5° north of Moon

1995: Final test flight of DC-X rocket
1998: First satellite launch from a submarine
2003: Mars rover Opportunity launched
2016: Soyuz MS-01 launched carrying ISS Expedition 48/49 crew

Sunday 8

1994: STS-65 Columbia launched
2009: First flight test of Max Launch Abort System
2011: STS-135 Atlantis launched, final shuttle mission