December 22

December 22 Leap Leap+1 Leap+2 Leap+3
1950 M8 SGR M8 SGR M8 SGR M8 SGR
W SGR W SGR W SGR
10Gamma SGR 10Gamma SGR
2000 M8 SGR M8 SGR 4 SGR 4 SGR
W SGR W SGR
10Gamma SGR

In some cases you have a choice of stars for this date. Remember that a brighter star has a smaller magnitude number, if that is your choice.

Name: 4 SGR
Birthday from Jack’s initial research: Dec 21
Magnitude: 4.7
Spectrum/Star type: Blue
Distance in Light Years: 435
Diameter compared to Sun: about 3x
Luminosity compared to Sun: about 50x
Date best observed: Aug 5
Additional information: This star is near the position of the December Solstice and the Lagoon Nebula, M8.

Name: Messier 8, SGR Lagoon Nebula
Birthday from Jack’s initial research: Dec 22
Magnitude: About 3.5, there is much disagreement, but visually it is bright.
Spectrum/Star type: Blue
Distance in Light Years: 5200
Date best observed: Aug 6
Additional information: Number 7 in Messier’s Catalog of objects he would not confuse with a comet.This is a very young object – only 2 million yrs old! It is both a bright nebula & star cluster 60 light-years in diameter. The location of the December Solstice is just above it. The “Lagoon”
description was first used by Agnes Clerke in 1890.

Name: W SGR sometimes called Gamma 1
Birthday from Jack’s initial research: Dec 22
MAG 4.6var, 4.3 to 5.0,
Spectrum/Star type: Light yellow to yellow supergiant
Distance in Light Years: greater than 2000
Diameter compared to Sun: about 50
Luminosity compared to Sun: about 2500
Date best observed: Aug 6
Additional information: W is a Cepheid variable with a 7.5day period. It is one of the most distant stars of the zodiac.

Name: 10Gamma SGR, Al Nasl, occasionally called Gamma 2
Birthday from Jack’s initial research: Dec 22
Magnitude: 3.0
Spectrum/Star type: Orange Giant
Distance in Light Years: 96
Diameter compared to Sun: ~15
Luminosity compared to Sun: 60+
Date best observed: Aug 6
Additional information: “The Point” of the Arrow, located in the heart of The Large Sagittarius Star Cloud.

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