ORION

(Abbrevation: Ori)

One of the most magnificent constellation in the sky, it represents the mythological hunter who boasted that he could kill any creature on earth, but who was fatally stung by a scorpion. The two leading stars are Rigel, which is actually a variable over a very small range (0.08 to 0.20) and the red variable Betelgeuse or Betalgeuze. The gaseous nebula M.42, in the sword, is the most famous example of its type, and is easily visible to the naked eye. Altogether there are fifteen stars above the fourth magnitude:

(p5 is an eclipsing binary with an extremely small range, and h is a b Lyræ eclipsing binary with a range of from 3.32 and 3.50).

BRIGHTEST STARS

STAR	R.A.			DEC			MAG.	ABS.MAG.	SPEC	DIST.”
STAR	H	M	S	o	‘	“	MAG.	ABS.MAG.	SPEC	DIST.”
1 p³	04	49	50.3	+06	57	41	3.19	3.8	F6	7.7
2 p²	04	50	36.6	+08	54	01	4.36	0.6	AO	55
3 p4	04	51	12.3	+05	36	18	3.96	-3.6	B2	280
4 o¹	04	52	31.9	+14	15	02	4.74	-	M3	32
8 p5	04	54	15.0	+02	26	26	3.72v	-3.6	B2	290
7 p¹	04	54	53.7	+10	09	03	4.65	0.9	AOp	83
9 o²	04	56	22.2	+13	30	52	4.07	-0.1	K2	68
10 p6	04	58	32.8	+01	42	51	4.47	-2.2	K2	190
11	05	04	34.1	+15	24	14	4.68	0.0	AOp	26
17 r	05	13	17.4	+02	51	40	4.46	-0.2	K3	86
19 b	05	14	32.2	-08	12	06	0.12v	-7.1	B8	280 RIGEL L/Y 900
20 t	05	17	36.3	-06	50	40	3.60	-2.2	B5	130
22 o	05	21	45.7	-00	22	57	4.73	-3.0	B2	340
29 e	05	23	56.7	-07	48	29	4.14	0.3	G8	58
28 h	05	24	28.6	-02	23	50	3.36	-3.5	B1	230 ALGJEBBAH
24 g	05	25	07.8	+06	20	59	1.64	-3.6	B2	110 BELLATRIX L/Y 360
30 y	05	26	50.2	+03	05	44	4.59	-3.0	B2	330
31 CI	05	29	43.9	-01	05	32	4.71	-0.3	K5	93
32 A	05	30	47.0	+05	56	53	4.20	-1.6	B5	150
36 u	05	31	55.8	-07	18	05	4.62	-4.1	BO	560 THABIT
34 d	05	32	00.3	-00	17	57	2.23v	-6.1	O9.5	720 MINTAKA
37 f¹	05	34	49.2	+09	29	22	4.41	-4.6	BO	570
39 l	05	35	08.2	+09	56	02	3.39	-5.1	O8	550 HEKA
42 c	05	35	23.1	-04	50	18	4.59	-3.6	B2	135
44 i	05	35	25.9	-05	54	36	2.76	-6.0	O9	570 HATYSA
46 Î	05	36	12.7	-01	12	07	1.70	-6.2	BO	370 ALNILAM L/Y 1200
40 f²	05	36	54.3	+09	17	27	4.09	0.2	KO	60
48 s	05	38	44.7	-02	36	00	3.73	-4.4	O9.5	550
47 w	05	39	11.0	+04	07	17	4.57	-2.9	B3	310
50 z	05	40	45.5	-01	56	34	1.77	-5.9	O9.5	340 ALNITAK L/Y 1600
53 k	05	47	45.3	-09	40	11	2.06	-6.9	BO.5	650 SAIPH
54 c¹	05	54	22.9	+20	16	34	4.41	4.4	GO	9.9
58 a	05	55	10.2	+07	24	26	var	-5.6v	M2	95 BETELGEUX L/Y 310
HD 40657	06	00	03.3	-03	04	27	4.53	-0.1	K2	80
61 m	06	02	22.9	+09	38	51	4.12	1.2	AO	37
62 c²	06	03	55.1	+20	08	18	4.63	-6.8	82	1000
67 n	06	07	34.2	+14	46	06	4.42	-1.7	B3	170
70 x	06	11	56.3	+14	12	31	4.48	-1.7	B3	170

d has long been classed as a variable, but is in fact an eclipsing star with a range of only 2.20 to 2.35 (period 5.73 days). h is also an eclipsing star with a range of only 0m.2. p5 is an ellipsoidal variable with a range of 0.1 mag.

DOUBLES

STAR	R.A.			DEC			MAGS.	P.A.	DIST.”
STAR	H	M	S	o	‘	“	MAGS.	P.A.	DIST.”
17 r	05	13	17.4	+02	51	40	4.5,8.6	063	FIXED
19 b	05	14	32.2	-08	12	06	0.1,7.0	2.06	FIXED
28 h	05	24	28.6	-02	23	50	3.7,5.1	083	FIXED
39 l	05	35	08.2	+09	56	02	3.7,5.6	041	FIXED
34 d	05	32	00.3	-00	17	57	2.3v,6.9	000	?
50 z	05	40	45.5	-01	56	34	4.2,4.2	164	VERY SLOW BINARY.P.A. INCREASING.

In addition there are the two famous multiples in the sword, q (the trapezium and s.

VARIABLS

STAR	R.A.		DEC		RANGE	PERIOD,D.	SPEC	TYPE
STAR	H	M	o	‘	RANGE	PERIOD,D.	SPEC	TYPE
W	05	02.8	+01	07	5.9---7.7	212	N	SEMI-REGULAR
S	05	26.5	-04	44	7.5---13.5	416	M	MIRA
58 a	05	55.2	+07	24	0.1---0.9	±2070	M	SEMI-REGULAR
U	08	52.9	+20	10	5.3---12.6	372	M	MIRA

The range and period of betelgeux are uncertaim. The star has been recorded as equalling or even surpassing rigel, and at other times descending to equality with aldebaran, but no precise limets are available. Generally betelgeux is comparable with procyon, appreciably fainter than rigel and obviously brighter then aldebaran.

CLUSTERS AND NEBULÆ

OBJECT	R.A.		DEC		TYPE	NOTES
	H	M	o	‘
NGC 1976 M.42	05	32.9	-05	25	NEBULA	‘SWORD OF ORION’. NAKED-EYE; CONTAINS THE MULTIPLE q
NGC 1982 M.43
NGC 2068 M.78	05	44.2	+00	02	NEBULA	MAG 8.3 REFLECTION NEBULA