SJAA

Ephemeris

Comet Comments

Don Machholz


Comet Linear (1998 M5) moves past the North Celestial Pole while Comet Williams fades in our evening sky. Periodic Comets Jager and Harrington-Abell remain near each other in our Winter Milky Way.

C/1998 A1 (Tilbrook): Justin Tilbrook of Australia visually discovered this comet on Jan 12. He was using an 8-inch reflector at 70x to find the tenth magnitude object. Justin was intentionally looking for comets when he found this, his second comet. His first comet find, 18 months ago, was accidental-he was checking out variable stars at the time. Comet Tilbrook is moving away from both the earth and sun, and dimming. During late December, while still undiscovered, it passed 30 million miles from us. I swept over it on December 9, when I picked up galaxy NGC 6217 but missed the equally faint comet, a couple of degrees away. Then on Jan. 3, shortly after moonrise, I swept over it when it was near Jupiter in the evening sky. Perhaps it brightened rapidly shortly before discovery.

COMET HUNTING NOTES: Five of the last seven visual discoveries (covering 2.5 years) have been made by Southern Hemisphere observers, all from Australia, and all five comets being found south of the celestial equator. Two were accidental finds (by Williams and Tilbrook), with Tilbrook finding one more and Tabur finding two.

Ephemerides

C/1998 M5 (LINEAR)
Date
(00UT) R.A. (2000)	Dec		El		Sky	Mag
02-11	19h24.7m	+60 deg. 37'	79 deg. 	M	9.0
02-16	19h28.9m	+64 deg. 21'	82 deg. 	M	9.0
02-21	19h33.2m	+68 deg. 26'	84 deg. 	M	9.0
02-26	19h37.8m	+72 deg. 49'	87 deg. 	M	9.0
03-03	19h42.9m	+77 deg. 30'	89 deg. 	M	9.0
03-08	19h49.2m	+82 deg. 24'	90 deg. 	M	9.0
03-13	20h03.8m	+87 deg. 29'	92 deg. 	M	9.1
03-18	07h38.5m	+87 deg. 20'	92 deg. 	E	9.1
03-23	07h52.5m	+82 deg. 09'	93 deg. 	E	9.2
03-28	07h58.9m	+77 deg. 03'	92 deg. 	E	9.3
04-02	08h04.3m	+72 deg. 05'	92 deg. 	E	9.5
04-07	08h09.4m	+67 deg. 21'	90 deg. 	E	9.6

C/1998 P1 (Williams)
Date
(00UT) R.A. (2000)	Dec		El		Sky	Mag
02-11	09h57.4m	+33 deg. 16'	160 deg. 	M	10.0
02-16	09h28.7m	+36 deg. 27'	155 deg. 	E	10.2
02-21	09h02.1m	+38 deg. 44'	148 deg. 	E	10.5
02-26	08h38.7m	+40 deg. 15'	140 deg. 	E	10.8
03-03	08h18.7m	+41 deg. 11'	132 deg. 	E	11.1
03-08	08h02.3m	+41 deg. 43'	124 deg. 	E	11.4
03-13	07h49.0m	+41 deg. 58'	117 deg. 	E	11.6
03-18	07h38.5m	+42 deg. 03'	111 deg. 	E	11.9
03-23	07h30.4m	+42 deg. 01'	105 deg. 	E	12.2
03-28	07h24.2m	+41 deg. 55'	99 deg. 	E	12.4
04-02	07h19.8m	+41 deg. 47'	94 deg. 	E	12.6
04-07	07h16.7m	+41 deg. 38'	88 deg. 	E	12.9

 
 
(00UT) R.A. (2000)	Dec		El		Sky	Mag
02-06	06h19.0m	+29 deg. 53'	137 deg. 	E	10.5
02-11	06h19.5m	+28 deg. 42'	132 deg. 	E	10.6
02-16	06h20.9m	+27 deg. 34'	127 deg. 	E	10.6
02-21	06h23.1m	+26 deg. 27'	123 deg. 	E	10.7
02-26	06h26.2m	+25 deg. 24'	119 deg. 	E	10.7
03-03	06h30.0m	+24 deg. 22'	115 deg. 	E	10.8
03-08	06h34.5m	+23 deg. 23'	111 deg. 	E	10.8
03-13	06h39.6m	+22 deg. 27'	107 deg. 	E	10.9
03-18	06h45.3m	+21 deg. 32'	104 deg. 	E	11.0
03-23	06h51.5m	+20 deg. 39'	100 deg. 	E	11.1
03-28	06h58.1m	+19 deg. 47'	97 deg. 	E	11.1
04-02	07h05.1m	+18 deg. 57'	94 deg. 	E	11.2
04-07	07h12.5m	+18 deg. 07'	91 deg. 	E	11.3


Date
(00UT) R.A. (2000) 	Dec		El		Sky	Mag
02-06	07h03.8m	+35 deg. 07'	145 deg. 	E	10.7
02-11	07h04.9m	+33 deg. 58'	140 deg. 	E	10.7
02-16	07h07.0m	+32 deg. 49'	136 deg. 	E	10.8
02-21	07h10.1m	+31 deg. 38'	132 deg. 	E	10.9
02-26	07h14.1m	+30 deg. 28'	129 deg. 	E	11.0
03-03	07h18.9m	+29 deg. 19'	125 deg. 	E	11.1
03-08	07h24.5m	+28 deg. 11'	121 deg. 	E	11.2
03-13	07h30.7m	+27 deg. 04'	118 deg. 	E	11.3
03-18	07h37.5m	+25 deg. 58'	115 deg. 	E	11.5
03-23	07h44.8m	+24 deg. 53'	112 deg. 	E	11.6
03-28	07h52.5m	+23 deg. 48'	109 deg. 	E	11.7
04-02	08h00.6m	+22 deg. 45'	106 deg. 	E	11.8
04-07	08h08.9m	+21 deg. 42'	103 deg. 	E	12.0

ELEMENTS

Object:			Williams	LINEAR (M5)
Peri. Date:		1998 10 17.838	1999 01 24.5733
Peri. Dist (AU):	1.14674 AU	1.742213 AU
Arg/Peri (2000):	294.473 deg.	101.2873 deg.
Asc. Node (2000):	156.379 deg.	333.3766 deg.
Incl (2000):		145.730 deg.	082.2285 deg.
Eccen:			1.0	1.0
Orbital Period:		Long Period	Long Period
Ref:			MPEC 32410	MPC 32410
Epoch:			1998 10 17	1999 01 22
Absol. Mag/"n":		6.5/4.0		5.5/4.0

Object:			Harrington-Abell	Jager
Peri. Date:		1999 01 27.8772		1999 03 07.7714
Peri. Dist (AU):	1.755993 AU		2.152631 AU
Arg/Peri (2000):	138.8996 deg.		179.4942 deg.
Asc. Node (2000):	337.2882 deg.		303.8178 deg.
Incl (2000):		010.2186 deg.		019.0944 deg.
Eccen:			0.542909		0.652672
Orbital Period:		7.53 years		15.4 years
Ref:			MPC 32595		MPC 32866
Epoch:			1999 01 22		1999 03 08
Absol. Mag/"n":		8.6/4.0			6.5/4.0


Don Machholz; last updated: October 04, 2007 Prev Next