Object/type:	Sigma Orionis / multiple star system
mag/dia/dist:	3.73 / separation 12.9", 42" / 1,400 ly
constellation:	Orion
date/time/place:	Jan 7, 01 / 23:00 / bangkok
trans'y/seeing/l-poll:	fair-poor / fair / medium-high
telescope:	newtonian 4.5" f8.8
eyepieces/power:	6mm / 166x
sky atlas page:

The bright star at the center is very close double star A&B, separation 0.25" can't be resolved with 4.5" telescope. Another visible two stars are 'D' mag7.5, separation 12.9" from A,B and 'E' mag6.0, separation 42" from A,B. Star 'C' mag10 was invisible. The total luminosity is 5,000 times of the Sun.
the small triple star at lower is Struve 761 mag8, 8.5 & 9
Star hopping: start at Orion belt, the belt is quite fit with FOV of finder scope center at Alnitak, Sigma Orionis locates near Alnitak, about 1/4 of distant of M42 & Alnitak. Home

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