October 22, 2012 - Color-Coding the Stars

Color-Coding the Stars Henry Norris Russell, one of the leading theoretical astronomers in America during the first half of the last century, was born 135 years ago this week. Russell worked at Princeton University for most of his professional life, serving as observatory director for thirty-five years. He is best known for his research on how the color (and thus temperature) of stars is related to their intrinsic brightness (or absolute magnitude). Along with Ejnar Hertzsprung, he developed the Color-Magnitude Diagram (more commonly known as the H-R diagram, after its creators), from which he concluded that stars evolve in a fairly predictable cycle from birth to death. Like all stars, the densely-packed stars in this Hubble Telescope image of the Sagittarius region vary in color according to their temperature.

Image credit: NASA / ESA / W. Clarkson (Indiana University and UCLA) / K. Sahu (STScI)

Weekly Calendar

October 22-28, 2012

Holidays - Sky Events - Space History

Moon phase Monday 22

Orionid meteor shower

2136 BC: First record of solar eclipse
1905: Karl Jansky born
1966: Luna 12 launched
1975: Venera 9 orbits Venus
1992: STS-52 Columbia launched

Moon phase Tuesday 23

1968: First powered flight of the HL-10 lifting body
2007: STS-120 Discovery launched
2012: Soyuz TMA-06M launched carrying ISS Expedition 33/34 crew

Moon phase Wednesday 24

United Nations Day

Neptune 6° south of Moon

1851: William Lassell discovers Uranus moons Umbriel & Ariel
1968: 199th and final X-15 flight
1998: Deep Space 1 launched
2001: Mars Odyssey arrives at Mars
2007: Chang'e-1 lunar spacecraft launched

Moon phase Thursday 25

Saturn in conjunction with Sun

1671: Giovanni Cassini discovers Iapetus, moon of Saturn
1877: Henry Norris Russell born
1975: Venera 10 lands on Venus
2006: STEREO spacecraft launched

Moon phase Friday 26

Mercury at greatest elongation (24° E)

1977: Fifth and final glide test of Space Shuttle Enterprise
2004: Cassini spacecraft completes first flyby of Titan

Moon phase Saturday 27

Uranus 5° south of Moon

1961: SA-1 launched, first Saturn rocket
2003: ISS Expedition 7 crew returns to Earth after 184 days in orbit

Moon phase Sunday 28

1971: Britain launches its first satellite
1974: Luna 23 launched
2009: Ares I-X test flight


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