djb@cbosgd.UUCP (02/26/84)
I just recently received my copy of the "International Halley Watch
Amateur Observers' Manual for Scientific Comet Studies" (by Stephen J.
Edberg) and am quite pleased. It is a treasure trove of information on
comet watching in general, and on Halley's Comet and its 1986 appearance.
The first part of the book is on methods, including information on
visual, photographic, astrometric, spectroscopic and photometric
studies. The second half contains a day-by-day ephemeris from 6/4/1985
through 5/4/1987, and a sequence of 19 specially modified AAVSO star
charts that show Halley's position in the sky from Nov. 1985 through
May 1986.
In addition, there is a section that describes the International Halley
Watch, an organization that will allow amateur astronomers to network
together and particpate significantly in the study of Halley's Comet.
Forms are included that allow you to register yourself as a member of
the network, and also for recording and reporting your observations.
A quick pass through the book is enough to convince you of the great
discrepancy between the appearance for northern hemisphere observers
and for those in the southern hemisphere. For example:
Date Dark Hours vs. Observers Latitude Magnitude*
(1986) 45 N. 30 N. 30 S. 45 S.
------------------------------------------------------------- (* Recent study
Mar. 7 0.2 0.9 2.0 2.0 4.5 (indicates that
17 0.5 1.5 3.3 3.7 4.5 (Halley's may be
27 0.7 2.3 5.3 6.2 4.3 (as much as two
Apr. 6 0 3.8 9.1 9.4 4.0 (magnitudes
16 6.0 8.3 10.0 9.9 4.4 (brighter than
26 6.2 8.0 9.2 10.0 5.5 (these values!
-------------------------------------------------------------
Dark hours are the interval during which the Sun is below the local
horizon by at least 18 degrees and the comet is simultaneously visible
above the local horizon. Notice the difference between the values for
observers at northern latitudes and those at southern latitudes. As
you would expect from the above table, the altitude of the comet is
similarly much better for southern observers:
Date Comet Altitude vs. Observers Latitude
(1986) 40 N. 30 N. 20 N. 20 S. 30 S.
------------------------------------------------------
March 6 5 10 15 22 22
16 8 15 24 40 40
26 10 20 30 59 60
April 5 6 15 27 65 73
10 - 10 15 49 55
------------------------------------------------------
Altitude is given in degrees at the beginning of morning astronomical
twilight.
I highly recommend this book to anyone planning to take more than
casual notice of Halley's Comet. It does assume some rudimentary
astronomical knowledge, but encourages any amateur observer to particpate
in the Halley's Watch network, regardless of skill level or equipment.
Dedication and patience are all that is required.
If you are interested, the book is available through Sky Publishing
(check any recent issue of Sky & Telescope for ordering info).
Me, I'm taking March 1986 off and heading for Australia or New Zealand.
* *
David Bryant
AT&T Bell Laboratories
* Columbus, OH 43213
* (614) 860-4516
* .
. djb@cbosgd.UUCP
cbosgd!djb@Berkeley.ARPA
* *GMS@PSUVM.BITNET (01/16/85)
An excellent article regarding where and when to view Halley's Comet
is the following:
"A User's Guide to Halley's Comet"
Dennis DiCicco, Sky and Telescope,
September, 1983, pp 211-212
The following information is mostly gleaned from that article.
Halley's comet will be visible during two periods of time extending
before and after perihelion. (The closest point in its orbit to the sun,
when it is essentially unobservable this time) These periods are from
about September 1 to November 1 1985, and April 1 to June 1 1986.
As for exactly where to look, that will depend on when you are looking.
Pick up an issue or two of either 'Sky and Telescope' or 'Astronomy'
magazine about a month or two ahead of time. They typically publish
maps. Otherwise you can get a copy of the "Observer's Handbook 1985"
from the Royal Astronomy Society of Canada (124 Merton St., Toronto
Canada, 1979), they will undoubtedly publish the coordinates and a map
or two.
A number of factors control how it will appear. Those you can't do anything
about include :
- the angles and circumstances of the comet's orbit with
respect to the Earth's orbit
- how much of the solid matter in the nucleus of the comet
is released into the ion and dust tails
Factors you can do something about include:
- generally the more south you are the better a view you will have
during the post-perihelion encounter, which coincidentally is
often the best time to observe a comet
- getting away from light pollution, air pollution and fog will
greatly improve your view, a mountaintop at least 100 miles from a
major city is best, but anywhere not in heavy light pollution
should be possible. It would be worthwhile to drive 20 miles to
get away from the lights.
To sum it all up, for Northern Hemisphere viewers, the best time is the
pre-perihelion encounter. The best days are November 15 - 18 when the
nucleus of the comet is passing just below the Pleiades star cluster
in Taurus. (The tiny dipper just about overhead at end of evening
twilight about this time of year)
The Moon will be new on Nov 12'th so for at least a few days, weather
permitting, it should be well placed for observation. Best bet is a
good set of wide-angle binoculars and a very dark sky.
I will be observing from Black Moshannon Mountain in Pennsykvania, anyone
passing through or living near this area is welcome to join me. (reply
via email) Happy observing!
"Waited 31 years for this!"
------------------------------------------------------------------------------
Gerry Santoro
Microcomputer Information and Support Center GMS @ PSUVM (bitnet)
Penn State University !psuvax1!santoro (UUCP)
101 Computer Building santoro @ penn-state (CSNET)
University Park, PA 16802
(814) 863-4356
- Member in good standing (I hope) of Amateur Astronomers Association
of Pittsburgh
- Leader of Penn State Eclipse Expedition - May, 1984 (:-)fbr@utastro.UUCP (Frank Ray) (01/06/86)
HELP!
In a friendly response to a net.astro reader, I offered a
comet brochure, and got 14 other requests for same. I will mail these out,
BUT please direct all other requests for the McDonald Observatory
comet brochure to the following:
McDonald Observatory News
RLM 15.308N
The University of Texas
Austin, Texas 78712
ALSO, one of the staffers in our public information office has graciously
consented to field electronic mail requests for the brochure, so if
you want to send a bruchure request via electronic mail, please direct
it to
anaid@utastro.UUCP
Also, ALSO, there's a really handsome poster on various comets called
"COMETS" available from the Hansen Planetarium, Salt Lake City, Utah.
There's probably a small fee but it's all tax deductible.
Cheers. fbrwales@ucla-cs.UUCP (01/15/86)
Last Friday, I photographed Halley's Comet in the Los Angeles area.
I am posting the details in case they may be helpful to others who
may try to see, and/or take pictures of, the comet when it reappears
in March. I would also welcome any suggestions for improvements in
my technique.
DATE/TIME OF SIGHTING: 10 January 1986, approx. 1845 PST
(11 January 1986, approx. 0245 UTC)
PLACE OF SIGHTING: In the hills near Malibu, CA (about 20 km west of
Los Angeles).
CONDITIONS: Sky was perfectly clear. Very slight wind. Some lights
from the few houses in the area. Could see stars down to about
4th or 5th magnitude with the unaided eye.
LOCATION OF COMET: Approximately 21h 57m RA, -4d 30' Dec (2000.0;
based on comparison of photos with Tirion Sky Atlas).
MAGNITUDE OF COMET: Between 5 and 6 (based on comparison of comet
image with nearby stars on photos). I could not see the comet with
the naked eye, but I could see it in 7x50 binoculars or telescope.
CAMERA: Pentax MX body, 50mm f/2 lens (no filter -- not even a skylight
filter); mounted piggyback on a Meade 2080 scope with motor drive
and dual-axis drive corrector. Lens was focused at infinity with
the lens wide open.
FILM: Stock (unhypered) Fujicolor 1600 color print film.
EXPOSURE: From 8 seconds to 8 minutes, in multiples of 2. (8-minute
exposures were best; 4-minute were OK; others probably not worth
the effort in this case.)
ALIGNMENT OF TELESCOPE: I do not have a special polar axis finder. I
aligned the telescope by sighting down the barrel, and fine-tuned
the motor drive rate by watching Jupiter for several minutes (using
an illuminated-reticle eyepiece). The pictures showed no noticeable
streaking (of course, by the nature of the technique they were wide-
angle, so this is not unexpected).
OTHER COMMENTS: Most of the pictures had several airplane trails. I am
going to try to enlarge a portion of the best print (showing the
comet, plus some nearby stars for location purposes); we'll see what
happens.
--
Rich Wales // UCLA Computer Science Department // +1 213-825-5683
3531 Boelter Hall // Los Angeles, California 90024 // USA
ARPA: wales@LOCUS.UCLA.EDU -or- wales@UCLA-LOCUS.ARPA
UUCP: ...!(ucbvax,ihnp4)!ucla-cs!waleskeith@fluffy.UUCP (Admin) (02/24/86)
For some time now I have been reading that the best viewing of Halley's comet will be in the Southern hemisphere in March and April. Does anyone know exactly how good the show will be? Will it still be so far away that binoculars will be needed to distinguish it from stars or will it be more easily seen? Keith Crews
anita@utastro.UUCP (Anita Cochran) (02/25/86)
In article <199@fluffy.UUCP>, keith@fluffy.UUCP (Admin) writes: > > For some time now I have been reading that the best > viewing of Halley's comet will be in the Southern hemisphere > in March and April. Does anyone know exactly how good the show > will be? Will it still be so far away that binoculars will be > needed to distinguish it from stars or will it be more easily seen? > > Keith Crews The comet will be no closer to the southern hemisphere of earth than to the northern hemisphere (okay, marginally but imperceptibly closer). The difference between seeing it in the northern and southern hemispheres is the height above the horizon that the comet will get to. If viewed from the southern hemisphere, the comet will be up for more of the night and will be higher above the horizon. This means that one will not have to fight the haze that is on the horizon even in non-polluted, dark sites. One will also have longer each night to view it. But, if one needs binoculars to see it in the northern hemisphere then one will need binoculars to see it in the southern hemisphere. The important thing in the north is to find a dark site (no city lights) with good viewing to the southeast horizon when it is a morning object (march and beginning of april) or a good southwest horizon in the end of april. I wouldn't expect to see it well if your latitude is much above 35 degrees N. Obviously, the further south you go, the better the conditions will be but there are plenty of good places to see the comet from the southwest of the U.S. -- Anita Cochran uucp: {noao, ut-sally, ut-ngp}!utastro!anita arpa: anita@astro.UTEXAS.EDU snail: Astronomy Dept., The Univ. of Texas, Austin, TX, 78712 at&t: (512) 471-1471
IBS@PSUVMB.BITNET (03/14/86)
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