Solwind-10 Images
I have found a small non-group comet in Solwind images of 1984 September 15/16.
It's well visible in 16 full frame
images from Sep 15 05:52:27 to Sep 16 08:50:57 UTC
and two partial frames at Sep 15 07:37:21 and 07:40:15.
From top to bottom: Sep 15 05:52:27, 07:37:21, 07:40:15,
08:55:05, 08:59:59, 09:04:52, 17:06:56, 17:11:49, 18:42:43,
18:47:36,
Sep 16 04:07:32, 04:12:25, 04:17:19, 04:22:12, 07:26:20,
07:31:13, 08:46:04, 08:50:57 UTC.
15 images stacked and aligned on one of
the hot spots.
I have measured rough R.A. and Decl:
| Time (Sep 15/16) | comet x | comet y | hot spot x | hot spot y | dx | dy | new x | new y | R.A. 2000.0 | Decl 2000.0 |
| 05:52:27 | 482 | 140 | 491 | 356 | +2 | -2 | 484 | 138 | 11 29.4 | +04 14 |
| 07:37:21 | 455 | 137 | 494 | 353 | -1 | +1 | 454 | 138 | 11 30.4 | +04 14 |
| 08:55:05 | 431 | 143 | 488 | 359 | +5 | -5 | 436 | 138 | 11 31.1 | +04 13 |
| 08:59:59 | 428 | 140 | 490 | 357 | +3 | -3 | 431 | 137 | 11 31.2 | +04 14 |
| 09:04:52 | 431 | 140 | 491 | 356 | +2 | -2 | 433 | 138 | 11 31.2 | +04 13 |
| 17:06:56 | 298 | 140 | 494 | 353 | -1 | +1 | 297 | 141 | 11 35.9 | +04 11 |
| 17:11:49 | 299 | 140 | 496 | 354 | -3 | 0 | 296 | 140 | 11 35.9 | +04 11 |
| 18:42:43 | 273 | 140 | 494 | 353 | -1 | +1 | 272 | 141 | 11 36.8 | +04 11 |
| 18:47:36 | 272 | 140 | 495 | 353 | -2 | +1 | 270 | 141 | 11 36.9 | +04 11 |
| 04:07:32 | 102 | 147 | 491 | 356 | +2 | -2 | 104 | 145 | 11 42.6 | +04 08 |
| 04:12:25 | 104 | 146 | 494 | 353 | -1 | +1 | 103 | 147 | 11 42.6 | +04 07 |
| 04:17:19 | 104 | 144 | 496 | 353 | -3 | +1 | 101 | 145 | 11 42.7 | +04 08 |
| 04:22:12 | 105 | 146 | 497 | 355 | -4 | -1 | 101 | 145 | 11 42.7 | +04 08 |
| 07:26:20 | 44 | 149 | 495 | 354 | -2 | 0 | 42 | 149 | 11 44.7 | +04 06 |
| 07:31:13 | 44 | 148 | 497 | 355 | -4 | -1 | 40 | 147 | 11 44.7 | +04 07 |
| 08:46:04 | 11 | 155 | 488 | 359 | +5 | -5 | 16 | 150 | 11 45.5 | +04 06 |
| 08:50:57 | 10 | 152 | 491 | 357 | +2 | -3 | 12 | 149 | 11 45.7 | +04 06 |
The images were enlarged three times
and measured to th nearest pixel. The comet's x,y are measured
from the upper left corner of the images (with the pylon on the
left side of the images). The measurements of the hot spot are
used to compensate for the image shift.
I have used a position angle of celestial north of 7.1 degree and
a plate scale of 70.2 arcseconds per pixel (as before) and the
suncenter at 118,122 to match the positions of beta Vir in images
of 1984 September 20.
Rainer Kracht 2005 July 30
With FindOrb (Bill Gray, www.projectpluto.com) I have derived these orbital elements:
Orbital elements:
Cxxxxxx
Perihelion 1984 Sep 17.430670 TT
Epoch 2001 Aug 19.0 TT = JDT 2452140.5 Kracht
q 0.115757 (2000.0) P Q
Peri. 72.78440 -0.61496609 -0.74259591
Node 153.04165 -0.73268091 0.66246369
e 1.0007803 Incl. 35.81300 0.29153966 0.09845382
From 16 observations 1984 Sep. 15-16; RMS error 62.663 arcseconds
840915 029 83.1+ 43.9+ 840915 029 75.0- 30.3- 840916 029 39.5- 15.5+
840915 029 66.2+ 53.6+ 840915 029 82.5- 7.6- 840916 029 78.7+ 15.4-
840915 029 14.4+ 2.3+ 840915 029 36.7- 6.3- 840916 029 34.2+ 47.1+
840915 029 61.3+ 62.9+ 840916 029 4.2+ 9.0+ 840916 029 70.8+ 27.4+
840915 029 18.5+ 3.5+ 840916 029 40.2- 48.8- 840916 029( 206+ 30.1+)
840915 029 31.3- 31.4- 840916 029 4.9+ 13.4+
Station data:
(029) Hamburg-Bergedorf (N53.4797 E10.2406).
Rainer Kracht 2005 August 02
With these orbital elements the
absolute magnitude H10 of the comet was close to mag 12.4.
It could have been visible in the southern evening sky in 1984
October.
Rainer Kracht 2005 August 03
The comet was announced as C/1984 R1 on IAUC 8583 with these orbital elements:
The following parabolic orbital elements are by B. G. Marsden. The comet seems not to belong to a known group.
T = 1984 Sept.17.42 TT Peri. = 78.74
Node = 152.84 2000.0
q = 0.1051 AU Incl. = 36.92
With these orbital elements the
absolute magnitude H10 of the comet was close to mag 12.8.
Rainer Kracht 2005 August 13