SECRIST%OAK.SAINET.MFENET@LLL-MFE.ARPA (01/30/86)
Date: Wed, 29-JAN-1986 23:50 EST
To: Space@Angband.Arpa
Message-ID: <[OAK.SAINET.MFENET].0A836F20.008E9C6C.SECRIST>
Quote: "May your future be limited only by your dreams." -- Christa McAuliffe
Organization: Science Applications Int'l. Corp., Oak Ridge, Tenn.
CompuServe-ID: [71636,52]
X-VMS-Mail-To: ARPA%"Space@Angband.Arpa"
From the East Coast Forth Board (affiliated with the Potomac Forth Interest
Group, Jerry Shifrin, SYSOP). The following text has been edited from the
original sources indicated.
-=<***>=-
Francis R. Scobee
Michael Smith
Ronald E. McNair
Ellison S. Onizuka
Judith Resnik
Gregory Jarvis
Sharon Christa McAuliffe
Let each of us carry on their mission in our hearts and souls
that humankind may one day share the heavens with them.
Richard Secrist
SECRIST%OAK.SAInet.MFEnet@LLL-MFE.Arpa
-----------------------------------------------------------------------------
* * * H A L L E Y F A C T S * * *
by Morrison, & Cole, c/o STAR-NET at (305) 639-0715 by modem
INTRODUCTION
Halley's [rhymes with "valleys"] Comet is composed of a small, bright
nucleus (probably 1-3 km across), surrounded by a much larger fuzzy head,
or "coma" (Latin for "hair"), 10 000 to 1 000 000 km across, and a fainter
gas (mainly carbon monoxide and nitrogen) and dust tail streaming away from
the head. Only the nucleus, composed of ice, dust, and stones mixed with
frozen gases, is solid. The total mass of the comet is approximately
65,000,000 metric tons.
WHERE IS IT?
This month the comet continues moving west and south, dipping below the
Great Square of Pegasus, through the Circlet of Pisces, and toward
Aquarius. It will brighten rapidly, from 6.4 at the beginning of the month
to 5.9 at the end. The comet will transit the north-south meridian at
about 18:00 and be about 50 degrees above the southern horizon (at 40
degrees north latitude). Note that this position and time mean that the
comet is moving into the sunset region of the sky, and will become
progressively washed out by the sunlight until its re-appearance in Spring.
COMET DATA FOR MID MONTH
Right Ascension: 03 hours 49.02 minutes
Declination: 23 degress 17.652 minutes (near Gamma Piscium)
Distance: 122 982 530 km from Earth
Magnitude: 6.2
Velocity: 32.31 km/s
OBSERVING THE COMET
During this month's moon-free "window" (1st to 15th), the comet should be
bright enough to spot easily in binoculars and finderscopes. It is several
arc minutes across, with a condensed nucleus and a small tail, which is
generally oriented away from Earth (hidden mostly - until Spring).
Binoculars (7x35, 7x50, or 10x50) will be perfect for an overall view.
They're portable, light, relatively inexpensive, and offer good light grasp
and ease in locating faint celestial objects like Halley's Comet. Although
telescopes may reveal subtle details in the head, they aren't wide-angle
instruments. Binoculars will be required to encompass the comet's tail.
PHOTOGRAPHING THE COMET
The simplest way to photograph the comet is to use a tripod and a 35 mm
camera with a cable release. Aim the camera and focus the lens for
infinity. A 30-second exposure will record bright stars and show the comet
as a non-stellar ball with a fuzzy tail. Exposures of more than 60-seconds
will record dimmer stars, but show trailed images of stars and the comet.
Choose a 28 to 50 mm lens (for adequate sky coverage) with a focal ratio of
f/4 or faster (for a brighter image). Tracking by mounting a camera with
normal or 135mm lens "piggyback" atop a motor-driven telescope is the only
way to manage longer exposures. For best results, use FUJICHROME color
slide film with marked ISO (ASA) value of 400. Ektachrome is a second
choice, due to real speed falling off in time exposures like these: marked
values of speed are NO indicator past 60 second exposures!!
NEXT MONTH
During January the comet moves into the barren star field of Aquarius,
which rapidly sinks into evening twilight during the month. It should
enter dim naked-eye visibility (5th magnitude) and be visible relatively
easily in binoculars or a finder telescope. The moon-free observing window
will be the 1st to the 15th.
EPHEMERIS FOR COMET HALLEY STARTING 11/20/1986
Courtesy of STAR-NET at (305) 639-0715 by modem
Comparing this current info to the tables that follow for April shows that
brightness (low value of "magntude") is part of the rationale for the best
expectations for seeing to occur in the Spring. A difference of 1.0 in mag
is a brightness ratio of 2.5, or more than one camera F stop. Only a more
detailed examination of the coordinate data will show those not familiar
with celestial charts that the comet is getting too close to the sun now
(contrast dies due to sun's glare), and will be too low on the horizon for
viewing from points in the USA when it re-appears in Spring. In April from
the Florida Keys, the comet will be within about 30 degrees above the
horizon, which is the region where atmospherics severely limit contrast and
definition of celestial objects.
PAGE 1 DAYS FROM COORDINATES: DISTANCES (AU): PREDICTED
DATE PERIHELION RA DEC SUN EARTH MAGNITUDE
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
1/ 1/86 -40 22:15 -02:35 1.00 1.18 5.3
1/ 2/86 -39 22:13 -02:49 0.99 1.20 5.3
1/ 3/86 -38 22:11 -03:02 0.97 1.22 5.2
1/ 4/86 -37 22:08 -03:15 0.96 1.24 5.2
1/ 5/86 -36 22:06 -03:28 0.94 1.26 5.2
1/ 6/86 -35 22:04 -03:41 0.93 1.28 5.1
1/ 7/86 -34 22:02 -03:53 0.91 1.29 5.1
1/ 8/86 -33 22:00 -04:04 0.90 1.31 5
1/ 9/86 -32 21:58 -04:16 0.88 1.33 5
1/10/86 -31 21:56 -04:27 0.87 1.35 4.9
1/11/86 -30 21:54 -04:39 0.85 1.37 4.9
1/12/86 -29 21:53 -04:50 0.84 1.39 4.8
1/13/86 -28 21:51 -05:01 0.83 1.41 4.8
1/14/86 -27 21:49 -05:11 0.81 1.42 4.7
1/15/86 -26 21:47 -05:22 0.80 1.44 4.6
1/16/86 -25 21:45 -05:33 0.78 1.46 4.6
1/17/86 -24 21:44 -05:42 0.77 1.47 4.5
1/18/86 -23 21:42 -05:53 0.76 1.49 4.5
1/19/86 -22 21:40 -06:04 0.74 1.50 4.4
1/20/86 -21 21:38 -06:15 0.73 1.52 4.4
Note: the coordinates RA & DEC are celestial coordinates that designate the
position in the sky relative to the star field, not your position on the
earth. Use them by comparison to the coordinates of something you can
recognize. The charts in Sky & Telescope magazine are exellent references
to aid in locating things (Sky & Tel's $18 is included in $20 dues for
membership in the Central FL Astronomical Society, Inc. - if you are
interested: contact CFAS or Star-Net by sending a note to Chuck Cole).
Comparing this info to the tables above for December or January shows that
brightness (low value of "magntude") is part of the rationale for the best
expectations for seeing to occur in the Spring and further South than the
Florida Keys. A difference of 1.0 in mag is a brightness ratio of 2.5, or
more than one camera F stop. Only a more detailed examination of the
coordinate data will show those not familiar with celestial charts that the
comet will be too low on the horizon for decent viewing from points in the
USA when it re-appears in Spring. In April from the Florida Keys, the
comet will be within about 30 degrees above the horizon, which is the
region where atmospherics severely limit contrast and definition of
celestial objects.
PAGE 1 DAYS FROM COORDINATES: DISTANCES (AU): PREDICTED
DATE PERIHELION RA DEC SUN EARTH MAGNITUDE
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
3/ 1/86 19 20:27 -16:21 0.73 1.26 3.5
3/ 2/86 20 20:25 -16:43 0.74 1.24 3.5
3/ 3/86 21 20:23 -17:06 0.75 1.21 3.5
3/ 4/86 22 20:22 -17:29 0.77 1.19 3.5
3/ 5/86 23 20:20 -17:51 0.78 1.17 3.6
3/ 6/86 24 20:18 -18:15 0.79 1.14 3.5
3/ 7/86 25 20:16 -18:41 0.81 1.12 3.6
3/ 8/86 26 20:14 -19:07 0.82 1.10 3.6
3/ 9/86 27 20:12 -19:34 0.83 1.07 3.6
3/10/86 28 20:10 -20:02 0.85 1.05 3.6
3/11/86 29 20:08 -20:32 0.86 1.02 3.6
3/12/86 30 20:06 -21:02 0.88 1.00 3.6
3/13/86 31 20:03 -21:34 0.89 0.97 3.6
3/14/86 32 20:01 -22:08 0.91 0.95 3.6
3/15/86 33 19:58 -22:43 0.92 0.92 3.6
3/16/86 34 19:55 -23:20 0.94 0.90 3.6
3/17/86 35 19:52 -23:59 0.95 0.87 3.6
3/18/86 36 19:49 -24:40 0.97 0.85 3.6
3/19/86 37 19:46 -25:23 0.98 0.82 3.6
3/20/86 38 19:42 -26:09 1.00 0.79 3.5
3/21/86 39 19:38 -26:57 1.01 0.77 3.5
3/22/86 40 19:34 -27:48 1.03 0.74 3.5
3/23/86 41 19:29 -28:42 1.04 0.72 3.5
3/24/86 42 19:24 -29:40 1.06 0.69 3.4
3/25/86 43 19:18 -30:41 1.07 0.67 3.4
3/26/86 44 19:12 -31:46 1.09 0.64 3.4
3/27/86 45 19:05 -32:54 1.11 0.62 3.4
3/28/86 46 18:58 -34:06 1.12 0.59 3.3
3/29/86 47 18:49 -35:22 1.14 0.57 3.3
3/30/86 48 18:39 -36:42 1.15 0.54 3.2
3/31/86 49 18:29 -37:00 1.17 0.52 3.1
4/ 1/86 50 18:17 -39:24 1.18 0.50 3.1
4/ 2/86 51 18:04 -40:49 1.20 0.48 3.1
4/ 3/86 52 17:48 -42:13 1.21 0.46 3
4/ 4/86 53 17:31 -43:35 1.23 0.44 3
4/ 5/86 54 17:12 -44:50 1.24 0.42 2.9
4/ 6/86 55 16:50 -45:56 1.26 0.41 2.9
4/ 7/86 56 16:27 -46:47 1.28 0.39 2.8
4/ 8/86 57 16:02 -47:21 1.29 0.38 2.8
4/ 9/86 58 15:36 -47:33 1.31 0.37 2.8
4/10/86 59 15:09 -47:22 1.32 0.37 2.8
4/11/86 60 14:42 -46:46 1.34 0.36 2.8
4/12/86 61 14:16 -45:48 1.35 0.36 2.8
4/13/86 62 13:52 -44:29 1.37 0.37 2.9
4/14/86 63 13:30 -42:55 1.38 0.37 3
4/15/86 64 13:10 -41:10 1.40 0.38 3.1
4/16/86 65 12:51 -39:18 1.41 0.40 3.2
4/17/86 66 12:35 -37:23 1.43 0.41 3.3
4/18/86 67 12:21 -35:28 1.44 0.43 3.5
4/19/86 68 12:08 -33:35 1.46 0.45 3.6
4/20/86 69 11:57 -31:46 1.47 0.47 3.7
4/21/86 70 11:48 -30:03 1.49 0.49 3.8
4/22/86 71 11:39 -28:24 1.50 0.51 4
4/23/86 72 11:31 -26:52 1.52 0.54 4.1
4/24/86 73 11:24 -25:25 1.53 0.56 4.2
4/25/86 74 11:18 -24:05 1.55 0.59 4.4
4/26/86 75 11:13 -22:49 1.56 0.62 4.5
4/27/86 76 11:08 -21:39 1.58 0.65 4.6
4/28/86 77 11:03 -20:34 1.59 0.68 4.8
4/29/86 78 10:59 -19:33 1.61 0.71 4.9
4/30/86 79 10:56 -18:37 1.62 0.74 5
5/ 1/86 80 10:53 -17:44 1.64 0.77 5.1
Courtesy of Greg Walz-Chojnacki c/o STAR-NET @ (305) 639-0715 by modem
Comet HARTLEY-GOOD, from STAR-NET
Here is the latest information on Comet Hartley Good from the Central
Bureau for Astronomical Telegrams. Note, by the way, that this comet is
more spectacular than Halley's through early January, due to placement in
the sky. The designation of Comet Hartley-Good is 1985l. Any future
uploads to STAR-NET on this comet will be named 1985l.DCx (where x is the
version, starting with 3) to reflect a nomenclature correction.
The comet is moving swiftly west toward the Sun. While the comet is
expected to attain reach a total maginitude of 6.6, when it reaches
perihelion in Ophiuchus it will be too close to the Sun to be seen well.
Nevertheless, it should be worth viewing with even modest telescopes. It
will also make a reasonable photographic subject. Look for it through
early December in the progressively earlier evening sky.
Below are the improved parabolic orbital elements, followed by the
ephemeris. I would appreciate observers' reports on this object. Please
include such circumstances as time, date, altitude of comet, instrument
(aperture and magnification), etc. Thanks.
T = 1985 Dec 9.092 w = 87.040 degrees (arg. of peri.)
W = 357.702 " (long. of asc. node)
q= .69435 i = 79.897
Ephemeris for Comet Hartley-Good (epoch 1950)
DATE | r.a | dec. | Delta | R | t. mag.
mm/dd |(hh mm.mm)| ( dd mm.m )| (AU) | (AU)
______|__________|____________|___________|________|_______
9/22 | 00 14.21 | -27.54.7 | 0.644 | 1.602 | 9.1
9/27 | 23 33.81 | -26 55.1 | | |
10/2 | 22 46.43 | -24 30.5 | 0.529 | 1.457 | 8.3
10/7 | 21 56.19 | -20.29.2 | | |
10/12 | 21 08.60 | -15 16.4 | 0.511 | 1.311 | 7.7
10/17 | 20 27.53 | -09 42.9 | | |
10/22 | 19 54.03 | -04 31.6 | 0.581 | 1.166 | 7.5
10/27 | 19 27.18 | -00 01.8 | | |
11/01 | 19 05.47 | 03 44.6 | 0.699 | 1.026 | 7.3
11/06 | 18 47.43 | 06 52.6 | | |
11/11 | 18 31.84 | 09 28.0 | 0.828 | 0.896 | 7.1
11/16 | 18 17.79 | 11 35.0 | | |
11/21 | 18 04.56 | 13 15.8 | 0.948 | 0.787 | 6.8
11/26 | 17 51.69 | 14 30.1 | | |
12/01 | 17 38.95 | 15 16.8 | 1.044 | 0.714 | 6.6
12/06 | 17 26.31 | 15 34.2 | | |
12/11 | 17 13.93 | 15 21.9 | 1.106 | 0.695 | 6.6
12/16 | 17 02.01 | 14 41.4 | | |
12/21 | 16 50.70 | 13 35.7 | 1.127 | 0.736 | 6.9
12/26 | 16 40.06 | 12 09.1 | | |
12/31 | 16 29.98 | 10 25.6 | 1.109 | 0.825 | 7.4
01/05 | 16 20.25 | 08 28.7 | | |
01/10 | 16 10.57 | 06 20.7 | 1.061 | 0.944 | 7.9
01/15 | 16 00.56 | 04 03.0 | | |
01/20 | 15 49.79 | 01 35.8 | 0.991 | 1.078 | 8.3
01/25 | 15 37.82 | -01 01.0 | | |
01/30 | 15 24.17 | -03 47.8 | 0.913 | 1.221 | 8.7