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(meteorobs) Comet Comments, March 1998
Greetings!
I had forwarded the following to Lew and some others.... he suggested that,
although slightly off the meteor topic.... that I forward it to the
list..... enjoy!
.........
Below are the Comet Comments from Don Machholz for March.... Don't miss all
the notes after the elements... they are interesting reading!
As an aside here, when he talks about only 4 in recent times found by
accident... Comet Kobayashi-Berger-Milon was also found independently by a
friend of mine in town here, Art Fraser... and several of us helped him
confirm it.... but he was number #4.. and they only take the first 3 names
:( There are several other Canadian comet discoverers who live in Ottawa...
Rolf Meier, whose place I observe from, who has 4 to his name, and Doug
George, who has his name on Skorichenko-George.
Just some ramblings over morning coffee...
- Cathy
Great White North
(Ottawa, Canada)
From: DonM353259@aol.com
Date: Sun, 8 Feb 1998 02:17:28 EST
To: kronkg@medicine.wustldot edu, bbs.ssolar@astro.gea.cesca.es,
mbh@el94.sawbdot gov.za, 37STAR@newton.phys.sci.chula.ac.th,
JMaloney7@aol.com, chuckh@starlink.com, JRSanf@aol.com,
jbryant@extro.ucc.su.oz.au, denis@kisa.iki.rssi.ru,
Trobert@earthlinkdot net, JBortle@aol.com, ratcliffem@clpgh.org,
andromed@atm.daldot ca, dave@bas.powernet.codot uk, chall@cyberusdot ca,
comet.ace@zianet.com, drpaul@humboldt1.com, gc4959@idot bekkoame.or.jp,
harincar@camworks.com, Musante@ecs.umassdot edu, NTZT04A@prodigy.com,
DonM353259@aol.com
Subject: CC for March
COMET COMMENTS FOR MARCH 1998 By Don Machholz
Only a couple of comets remain in our sky this month. Comet Hale-Bopp
fades in our southern sky. Comet Meunier-Dupouy travels through our
morning northern sky. The only new finds this past month was by the SOHO
satellite, which monitors the solar vicinity. It discovered four more
comets, it has now found forty in less than two years. Like most of the
others, these four comets disappeared after going behind the sun.
COMET HUNTING NOTES: Forty-eight of the last 100 visual comet
discoveries were made by amateurs using reflectors. They range in size
from 4" to 19.5". The most popular size (16" aperture) was used in 16
finds. They were also efficient, averaging 231 hours per find compared
with 391 hours for all visual comet discoveries. All five accidental
comet discoveries (Berger, Milon, Hale, Bopp and Tillbrook) were made
with reflector telescopes.
EPHEMERIDES
C/1997 J2 (Meunier-Dupouy)
Date(00UT) R.A. (2000) Dec El Sky Mag
02-11 20h43.9m +34o38' 50o M 11.6
02-16 20h52.3m +34o08' 49o M 11.6
02-21 21h00.3m +33o41' 48o M 11.6
02-26 21h08.1m +33o17' 47o M 11.7
03-03 21h15.5m +32o56' 46o M 11.7
03-08 21h22.7m +32o37' 46o M 11.7
03-13 21h29.5m +32o21' 46o M 11.7
03-18 21h36.0m +32o07' 46o M 11.7
03-23 21h42.2m +31o54' 46o M 11.7
03-28 21h48.0m +31o44' 47o M 11.7
04-02 21h53.6m +31o35' 48o M 11.7
04-07 21h58.8m +31o27' 50o M 11.7
C/1995 O1 (Hale-Bopp)
Date(00UT) R.A. (2000) Dec El Sky Mag
02-11 05h03.3m -60o33' 88o E 8.5
02-16 04h59.8m -59o45' 87o E 8.6
02-21 04h57.3m -58o57' 86o E 8.7
02-26 04h55.6m -58o08' 85o E 8.8
03-03 04h54.7m -57o20' 84o E 8.9
03-08 04h54.6m -56o33' 83o E 9.0
03-13 04h55.1m -55o48' 82o E 9.0
03-18 04h56.2m -55o04' 82o E 9.1
03-23 04h57.8m -54o22' 81o E 9.2
03-28 04h59.9m -53o43' 80o E 9.3
04-02 05h02.4m -53o06' 79o E 9.3
04-07 05h05.3m -52o32' 78o E 9.4
55P/Tempel-Tuttle
Date(00UT) R.A. (2000) Dec El Sky Mag
03-03 01h13.2m +08o27' 38o E 10.7
03-08 01h12.7m +07o01' 32o E 11.0
03-13 01h12.3m +05o46' 27o E 11.3
ELEMENTS
Object: Hale-Bopp Meunier-Dupouy Tempel-Tuttle
Peri. Date: 1997 04 01.1347 1998 03 10.4365 1998 02 28.1034
Peri. Dist (AU): 0.914008 AU 3.051015 AU 0.976639 AU
Arg/Peri (2000): 130.5787 deg. 122.6755 deg. 172.4930 deg.
Asc. Node (2000): 282.4653 deg. 148.8429 deg. 235.256 deg.
Incl (2000): 089.4268 deg. 091.2731 deg. 162.4861 deg.
Eccen: 0.995085 1.000760 0.905507
Orbital Period: ~2500 years Long Period 33.23 years
Ref: MPC 30738 MPC 30738 MPC 30244
Epoch: 1997 12018 1998 03 08 1997 12 18
Absol. Mag/"n": -1.0/4.0 4.0/4.0 10.0/10.0
Don's Comet Hunting Hours
Comet Hunting Hours 1975-1997: 6277.25
Hours through Jan. 1998: 7.25
Total hours at last discovery (10-8-94): 5589.00
Least hours in any month since I began comet hunting on 1/1/75: 4.50
(01/86),
5.50 (02/80)
Most hours in any month since I began comet hunting: 69.25 (05/76), 63.00
(05/78)
COMET HUNTING NOTES FROM JULY 1997: Of the 97 visual comet discovery
events since 1/1/75-during which 73 comets were found and named- only
four times was the comet found by accident. In early July 1975 Doug
Berger and the late Dennis Milon found a comet while observing M 2. It
had been found the previous day by a comet hunter (Toru Kobayashi of
Japan). Then, twenty years later Alan Hale and Thomas Bopp chanced upon
a new comet near M 70.
COMET HUNTING NOTES FROM AUGUST 1977: With Tabur's find, six of the last
seven visually-discovered comets have been found south of the celestial
equator; and 14 of the last 17 visually-discovered comets have been
found in the morning sky.
COMET HUNTING NOTES FROM SEPT. 1997: Many people quote the 1700 hours it
took me to find my first comet or the 1742 hours to find my second.This
has been surpassed twice in recent years. In 1987 Noboru Nishikawa took
3024 hours in 2389 sessions to find his first comet (1987a). In 1990
Yuji Nakamura discovered his first comet after searching 2236.5 hours in
1558 sessions.
COMET HUNTING NOTES FROM OCT. 1997: With so many comets from the Kreutz
Sungrazing Group being discovered by the SOHO satellite, amateurs have
taken a renewed interest in sweeping along the path by which these
comets are arriving. That path is now in the morning sky, having been
behind the sun this past summer. The comets are very faint in the weeks
before perihelion and it may take CCD imaging to capture them. The
brightest members, although rare, can still be discovered visually.
COMET HUNTING NOTES FROM NOV. 1997: Since the first day of 1975, 76
comets have been visually discovered. Some have been discovered by more
than one person: ten by two visual discoverers and seven by three. This
amounts to 100 visual discovery events.
Thirty-two of those 76 comets were found in the evening sky with 44
found in the morning sky.
Additionally, 42 were found in the north of the celestial equator with
34 found south. All of the 23 comets found by observers living south of
the equator were found in the southern celestial sky. Northern
Hemisphere observers found comets both north and south of the equator.
COMET HUNTING NOTES FROM DEC. 1997: Since January 1975, 48 different
individuals have visually discovered comets that now carry their names.
What countries do they live in? Twenty-three are in Japan, nine reside
in the USA, with four in Australia.
Other countries represented are the old USSR, Canada, England, South
Africa, Philippines, Italy, New Zealand and Norway. The most discovery
events occurred in Japan (33) followed by the USA (30) and Australia
(19).
COMET HUNTING NOTES FROM JAN. 1998: Of the last 100 visual comet
discoveries, 28 were made by amateurs using binoculars. The smallest
pair of binoculars used was 7x35's by William Bradfield in 1980 to find
a magnitude-six comet. Three were the 80mm size while six finds were
made using binoculars with objectives of 110-120 mm. Four finds were
made with my homemade binoculars (130mm). And half (14) of all binocular
comet discoveries were made with 150mm (6-inch) binoculars.
COMET HUNTING NOTES FROM FEB. 1998: Of the last 100 visual comet
discoveries, 23 were made by amateurs using refractor telescopes. The
smallest was Genichi Araki's 3" scope to find Comet IRAS-Araki-Alcock.
Toshio Haneda used a 3.3" refractor to find his comet and three other
instruments were from 4.8 to 5.2 inches in diameter. The remaining 18
refractors were 6" in size, with William Bradfield finding 12 comets
since 1975 (and two before) with his 6" telescope.
Notes To Help You Make Better Use Of Comet Comments
by Don Machholz
Each issue of Comet Comments is written three weeks before the "due"
date, giving time for it to be distributed to the editors and placed
into the newsletters. Comet Comments contains information about new
comet discoveries. This is followed by comet news and observing tips for
the comets currently visible. Next I provide ephemerides (predicted
positions) for bright comets (usually all those brighter than magnitude
11) so that amateurs can find them. This is how to read these tables:
Date: This is the Universal Time for the comet's position. The positions
are for 00 hr UT. The United States is a few hours earlier than this, so
for a comet viewable in the evening, look for it on the night preceding
the indicated date. For morning viewing the comet has already passed the
position indicated for 00hr UT position, so the comet has passed that
point and moved on.
RA. and Dec: Right Ascension and Declination in 2000 equinox
coordinates. These can be plotted on a star chart and found by
star-hopping, or by using setting circles.
El: The elongation of the comet- the number of degrees it is from the
sun as seen from the earth.
Sky: Morning (M) or evening (E) sky.
Mag: The predicted magnitude or brightness of the comet. The brightness
of a comet is difficult to predict so this is only a guess based upon
past performance and comet theory.
The last item I include is the elements of the orbits. This information
can be entered into most comet orbit computer programs to further
project the comet's positions.
Peri. Date: The date the comet is closest to the sun. Year is followed
by month and day.
Peri. Dist: The distance from the comet to the sun at perihelion in
Astronomical Units.
Arg/Peri, Asc. Node, Incl: These define the angle of the comet's orbit.
The Arg/Peri is the Argument of the Perihelion; if this figure is under
180 the comet reaches perihelion north of the ecliptic. The Asc. Node is
the Ascending Node. The Incl is the inclination of the comet's orbit.If
it is under 90 degrees indicates the comet is in a direct orbit, while
over 90 degrees means it is in a retrograde orbit.
Eccen: This is the shape of the orbit. A "1.00" is a parabola, while
"0.00" is a circle. An eccentricity of greater than 1 is a hyperbola
orbit-the comet will never return.
Orbital Period: The length of time it takes for the comet to orbit the
sun.
Ref: The source giving the elements. MPC indicates Minor Planet
Circulars by the Smithsonian.
Epoch: The time for which the orbit is most accurate. The orbit is
generally accurate enough for visual location of the comet for several
months on either side of this date.
Absol. Mag/"n": This is the absolute magnitude- the brightness of the
comet if it were 1 AU from both the earth and the sun. The average comet
is about 7.0.
The "n" value is the rate of brightening as the comet nears the sun, or
dimming as it leaves the sun. The average is 4.0. The "n" value
presented here may have to be multiplied by 2.5 to enter into some
computers.