SPECTROSCOPY AND SPECTROPHOTOMETRY NETWORK
1. INTRODUCTION
During the years 1983-88, the Spectroscopy and Spectrophotmetry Network
(SSN) of the International Halley Watch (IHW) was responsible for
coordinating, collecting, and archiving a wide diversity of spectroscopic
observations of the periodic comets Halley, Giacobini-Zinner, and Crommelin.
The personnel of the Discipline Specialist Team in 1982-1989 is listed in
Table I. The spectral domain covered the ultraviolet and visible regions,
from about 1100 A to 10,000 A, with the ground-based data representing the
bulk of the spectra and covering 3000 A to 10,000 A. Spectra of comets
obtained in the wavelength regions longer than 10,000 A (1 micron) have been
archived by the Infrared Network.
The spectra of comet Halley taken from Earth have spatial resolutions
of about 400 km at best. Such spectra obtained remotely arise from three
distinct sources in the coma: (1) sunlight scattered by the coma dust, (2)
neutral molecular gas fluorescing with the solar radiation, and (3) molecular
and atomic ions also excited by resonance fluorescence. Solar radiation
reflected directly from the nucleus of the comet contributes negligibly to
the spectrum observed from Earth, except when a comet is at relatively large
heliocentric distances (>5 AU). Spectra in the IHW archive obtained with the
instrument aperture centered on the brightest part of the coma are generally
dominated by the neutral molecular spectrum of the coma. Spectra offset
projected distances >100,000 km from the brightest coma region toward the
tail (anti-solar direction) are generally dominated by molecular ions which
populate the plasma tail of the comet.
Both the coma and plasma tail spectra are composite with an underlying
continuous spectrum contributed by the solar radiation scattered by the comet
dust. Thus when analyzing the gaseous component of the spectrum, the dust-
reflected solar continuum is usually subtracted from the composite spectrum.
The spectra of Comet Halley presented in this archive can be found in various
forms, both with and without the correction for the solar background
continuum. The state of each archive spectrum can generally be determined by
reading its fits header. Some observers have submitted spectra of solar
system objects or scattered twilight to provide a solar spectrum with the sam
instrument used to observe the comet. These spectra have been archived with
the Halley spectra and can be used to subtract the background solar spectrum
from the comet spectrum. Also included in the IHW archive as appendices are
two high resolution spectra obtained directly of the Sun, which, when
convolved with the appropriate instrument profile and corrected for the
scattered light wavelength dependence (1/lambda), can be used to correct the
composite comet spectra for scattered sunlight.
Table I. Discipline Specialist Team of the Spectroscopy and Spectrophotometry
Network
_____________________________________________________________________________
Team Member Affiliation Responsibility
_____________________________________________________________________________
Susan Wyckoff Physics-Astronomy Department Discipline Specialist
Arizona State University
Tempe, AZ 85281
U.S.A.
Peter A. Wehinger Physics-Astronomy Department Discipline Specialist
Arizona State University
Michel C. Festou Observatoire de Besancon Discipline Specialist
F-2544 Besancon Cedex
France
David Schleicher Physics-Astronomy Department Computer System Manager,
Arizona State University Scientific Programmer &
Post-doctoral Fellow
Barbara Boothman Physics-Astronomy Department Computer System Manager &
Arizona State University Scientific Programmer
David Reisinger Physics-Astronomy Department Computer System Manager &
Arizona State University Scientific Programmer
Anthony J. Ferro Physics-Astronomy Department Scientific Programmer & Data
Arizona State University Assistant
R. Mark Wagner Physics-Astronomy Department Post-doctoral Fellow
Arizona State University
Uri Carsenty Physics-Astronomy Department Post-doctoral Fellow
Arizona State University
Marvin Kleine Goodyear Aerospace Corp. Software Consultant
Tobias Kreidl Lowell Observatory Software Consultant
Flagstaff, AZ 86001
Patricia Monger Astronomy Department Software Consultant
University of California
Berkeley, CA 94720
S.G. Djorgovski Astronomy Department Software Consultant
University of California
Berkeley, CA 94720
Kyle Baird Physics-Astronomy Department Student Assistant
Arizona State University
Lisa Engel Physics-Astronomy Department Student Assistant
Arizona State University
Ichishiro Konno Physics-Astronomy Department Student Assistant
Arizona State University
Carla Landenburger Physics-Astronomy Department Student Assistant
Arizona State University
Thomas Larson Physics-Astronomy Department Student Assistant
Arizona State University
Eric Lindholm Physics-Astronomy Department Student Assistant
Arizona State University
Gregory Loper Physics-Astronomy Department Student Assistant
Arizona State University
Steven Tegler Physics-Astronomy Department Student Assistant
Arizona State University
Jill Theobald Physics-Astronomy Department Student Assistant
Arizona State University
Maria Womack Physics-Astronomy Department Student Assistant
Arizona State University
Carol Taylor Physics-Astronomy Department Secretary & Word Processor
Arizona State University
Loretta McKibben Physics-Astronomy Department Secretary & Word Processor
Arizona State University
Beverly Dunlap Physics-Astronomy Department Secretary & Word Processor
Arizona State University
_____________________________________________________________________________
The comet Giacobini-Zinner Spectroscopic Archive contains 433 spectra
while the comet Halley archive includes more than 3500 spectra. The spectra
of P/Crommelin were originally published in the Archive of Observations of
Periodic Comet Crommelin (JPL Publication 86-2, edited by Z. Sekanina). In
addition, the P/Crommelin spectra in digital format were included on the
P/Giacobini-Zinner compact disk (5.25-inch CD-ROM). The digital archives
of P/Giacobini-Zinner and P/Halley contain a significantly greater number
of spectra than originally expected. The bulk of the comet Halley spectra
was received and archived between 1987 and 1989. The overall effort
involved contributions from approximately 150 observers in 16 countries at
more than 80 observatories or astronomical institutes. The response of the
astronomical community to the IHW archive was most positive and cooperative.
We owe a great debt of thanks and appreciation to our colleagues scattered
around the world who very kindly provided copies of their spectra for the
archive and for the good of all. The following sections provide a brief
description of the spectroscopic archive.
There are three additional files associated with the Spectroscopy networ
located in this appendix directory. They are:
SP_CODES.IDX--A table giving the translations for the spectroscopy key-
word DIS-CODE. This is a delimited file and can be read into most data-
base programs.
SP_HIST.DAT--A data file with (X,Y) pairs, giving the number of observa-
tions in the spectroscopic archive and the Julian date.
SOL_ATLS--A directory containing two solar atlases in FITS format.
2. SPECTROSCOPIC DATA ARCHIVE
The spectroscopic archive consists of data obtained by a wide variety
of observers, instruments, and techniques. The range of observation sites
spans the globe and includes the upper atmosphere and satellites in Earth
orbit. The spectroscopic observations of Comet Halley were monitored, but
not coordinated, by the Spectroscopy Center at Arizona State University.
Various individual observing programs were planned and executed in their
entirety by the observers who contributed data to the archive. Occasionally
the observations were made by observers who had no expertise in cometary
spectroscopy. Fortunately, there was such an overwhelmingly universal
interest in Comet Halley that virtually every large aperture telescope
equipped with spectroscopic instrumentation obtained at least a few spectra
of the comet. Thus, the spectroscopic archive comprises data obtained with
a very diverse array of state-of-the-art instruments and detectors in the
years 1985-1986 and represents a unique set of observations of Comet Halley.
In 1910, the state-of-the-art detector was the photographic plate. The
present archive includes a small percentage (<0.5%) of spectra digitized from
photographic plates, which is a testimony to the technological advances made
in astronomical detectors during the past 76 years and especially in the 1970
and 1980s. Our task to archive this diverse data set was a challenging one.
Because of the diversity of the data, we decided to exercise as little
editorial prerogative as possible when considering data to be included in
the archive.
Our standard keywords are listed in Sec. 11. They were used to explain
a large variety of different types of data, even though no finite set can
explain all possible types of data. For example, in the case of the
International Ultraviolet Explorer (IUE) satellite, the site location (in
a geosynchronous orbit) could not be described in terms of latitude,
longitude, and elevation, since these values constantly changed. In this
case, we entered mean values for the latitude and longitude of the satellite'
position projected onto the Earth, and a negative value for the elevation was
used as a flag that this elevation is inherently variable.
The spectroscopic data in the Comet Halley archive consist of two basic
types: one-dimensional and two-dimensional spectra. In the case of one-
dimensional spectra, the data are measurements vs. wavelength of the flux fro
the comet within a solid angle determined by the size of the spectroscopic
instrument aperture projected at the comet. For the two-dimensional spectra,
a spatial dimension is added covering the length of the slit projected at the
comet. Thus a two-dimensional spectrum contains flux information for a set o
points, determined by the slit length used. The two-dimensional spectra can
be treated as a normal image, as far as manipulation and display. The only
difference from an image is that one dimension is wavelength and the other is
spatial. The one-dimensional spectra might be displayed as a one-dimensional
image, but a graphical display, plotting flux vs. wavelength is more
conventional.
We adopted a policy in producing the archive to minimize editing and
altering the data submitted to avoid their interpretation. Thus we made no
attempt at calibrating the spectra that were submitted in raw, unreduced
form. Instead, we included calibration spectra in the archive, so that
users may manipulate data in the form submitted by the observer, and not
subjected to potential misinterpretation or changes by us as editors. We
felt that this policy best protected the integrity of the data for use by
future generations of astronomers. We have taken the position that we,
as archivists, should not be involved with actual reduction of the data,
which is why we requested that observers submit data to us in reduced
form (i.e., F(lambda) vs. lambda versus rho).
There are valid arguments on both sides of the issue whether submitted
data should have been reduced or left in their raw form. Future workers
may have better reduction techniques and the original observer may not be
interested in doing the full reduction, or may not have experience in
reducing cometary spectra. On the other hand, the observer, who is familiar
with the instrument used, probably knows his data best, and is in the best
position to make judgements as to what reduction techniques are proper. We
have taken the position that fully reduced data (flux and wavelength
calibrated) are the norm, but have archived what was sent. Most of the
data in the archive are fully reduced, or as fully reduced as possible
(in some instances, such as high spectral resolution data, flux calibration
may not be possible). In some sets, the data are raw, essentially as
observed. Hopefully with the raw data sets, other calibration data
have been included as well, although this is not always the case. When
calibration frames are available, their type should be clear from the
OBJECT keyword. The type of data presented can be determined from DAT-TYPE.
Data and calibration frames should be correlated, based on time and date
of observation, observer, and observatory.
A major source for information regarding observatories (location, name,
elevation, etc.) was the Astronomical Almanac, published by the US Printing
Office. This was only used when the observer did not furnish exact
information, such as latitude and longitude of the observatory.
As described in the FITS Keywords Descriptions, the OBSERVER and SUBMITT
keywords contain the name of the first observer or submitter. If there are
more than two names, all but the first name go in a special COMMENT ADD. OBS.
field. Most names are generally not a problem. However, due to the FITS
conventions, there can be problems with names which contain an apostrophe.
For example, OBSERVER = 'A'HEARN,M' is valid (the apostrophe after A is withi
the minimum eight characters for the keyword value), but OBSERVER =
'FELDMAN,P/A'HEARN,M' is not valid (it would likely be read in as OBSERVER =
'FELDMAN,P/A'). We have tried the solution of replacing the apostrophe with
blank. Thus we have OBSERVER = 'FELDMAN,P/A HEARN,M'. This may present a
slight problem when a search is made spelling the name A'Hearn properly.
The airmass of the observation was not always submitted to us. When we
were given hour angles, we did calculate the airmass. However, there are man
submissions for which no airmass is given. The proper airmass, if needed, ca
be obtained from the ephemeris for that time and the location of the observa-
tory.
There are no standard ways for describing the position of a slit with
respect to a comet. To describe the location of the slit. we chose three
measurements: (1) The distance between the center of brightness of the comet
and the center of the slit, measured in arcseconds (SEPNUC); (2) the angle,
measured in degrees from north throught east, to the center of the slit
(ORIENT); and (3) the angle, measured in degrees from north through east, of
the beginning of the slit (POSANG). Unfortunately, most observers do not use
these exact measurements. Often, the only measurement refers to the number
of arcseconds sunward or tailward. We have tried to convert the pointing
angles given to our three parameters as accurately as possible. Often we
used the comet's ephemeris for converting from tailward-sunward coordinates
to those used in the archive. It is a general convention that if the nucleus
is in the data frame, the slit is "on the comet," even though, strictly,
SEPNUC is not zero, but it is very small.
3. TRIAL RUNS 1983-85: RECOVERY, SPECTROSCOPIC HIGHLIGHTS, LESSONS LEARNED
The first trial-run observations and archiving campaign centered on
Periodic Comet Crommelin, which was recovered August 11, 1983 by L. Kohoutek
at the Calar Alto Observatory in Spain and independently by S. Wyckoff and
P. Wehinger at the Kitt Peak National Observatory in Arizona when the comet's
total V magnitude was 19.7. While P/Crommelin only reached a maximum total
brightness of 7.5 mag, spectroscopically it was very rich in NH2.
Among the lessons learned in this trial run, the range of dates
selected for coordinated observations was not optimized for best coverage,
i.e., the largest elongation from the Sun and the maximum brightness. Due
to limited advanced notice of the coordinated observations, only a small
number of observers participated in the P/Crommelin campaign.
The second trial run involved Periodic Comet Giacobini-Zinner. Pre-
recovery images were obtained with CCDs in May 1984 by H. Spinrad and M.
Belton (private communication) using the KPNO 4-meter telescope, on January
28, 1985 by R.M. West using the ESO/Danish 1.5-meter telescope, and on March
28, 1985 by M. Belton and P. Wehinger using the KPNO 0.9-meter telescope.
Subsequently, S. Djorgovski, H. Spinrad, G. Will, and M. Belton recovered
P/Giacobini-Zinner on April 10, 1989 with the KPNO 4-meter reflector, when th
comet's total brightness was 22.5 mag. P/Giacobini-Zinner was the first come
to be visited by a spacecraft, when the NASA International Cometary Explorer
(ICE) passed through the plasma tail of this comet, 7800 km from the nucleus,
on September 11, 1985 at 11:02 GMT.
What lessons were learned in this case? Here the encounter was well
timed for coordinated simultaneous ground-based observations in predawn hours
in the U.S. desert southwest (11:02 GMT = 04:02 MST). However, very limited
information was provided by NASA's Mission Control to ground-based observers
prior to the ICE encounter. Details were not available about such things as
the track orientation of ICE through tail of the comet and the rate of motion
across the tail. Only about 5% as many data were acquired on P/Giacobini-
Zinner as compared with P/Halley. There was little, if any, formal
announcement to the comet community of plans to create a digital archive of
P/Giacobini-Zinner data.
There is one general remark to make about all three periodic comets with
regard to their recoveries. P/Crommelin, P/Giacobini-Zinner, and P/Halley
were all recovered during dark of the moon on telescope time originally
assigned to quasar imaging with CCDs. Since the orbits were well established
the relatively small fields of the CCDs were successful in the recovery
efforts. The situation was different for P/Brorsen-Metcalf, which was some
15 degrees away from its predicted position due to neglected non-gravitationa
forces since the last apparition in 1919.
Prior to P/Halley's 1980's return, bright comets of special interest
included: Humason 1962 VIII, in which CO+ was detected; Bennett 1970 II, whic
had a high dust content; Kohoutek 1973 XII, in which H2O+ was first detected;
West 1976 VI, in which CO+ and CO2+ were both detected; and IRAS-Araki-Alcock
1983 VII, in which S2 was detected close to the nucleus.
Bright comets following P/Halley in the period 1987-90 included: Wilson
(1987 May), total magnitude, m1 = 5.0 mag; P/Brorsen-Metcalf (1989 August),
m1 = 5.6 mag; Okazaki-Levy-Rudenko (1989 December), m1 = 5.8 mag; Austin (199
May), m1 = 5.0 mag, and Levy (1990 September), m1 = 4.0 mag (estimated).
P/Brorsen-Metcalf has a period of 70 yr, similar to that of P/Halley, but
the former comet is in a prograde orbit.
4. RECOVERY OF PERIODIC COMET HALLEY
P/Halley was recovered 1982 October 16 by David Jewitt, Alan Dressler.
Maarten Schmidt, and others using the Palomar Observatory 5-meter telescope.
Lest it be lost in the sands of time, we wish to point out that Alan
Dressler's efforts were crucial in leading to the recovery. Dressler
suggested that Jewitt make use of an occulting mask to suppress the
scattered light from an 8th magnitude star close to the predicted track of
P/Halley on October 16, 1982. Without the occulting mask, the 25.9-magnitude
comet would have been lost in the star's light. However, with Dressler's
occulting mask, plus dark clear sky and good seeing, the recovery attempt
was a success. Others who contributed in their community-minded spirit to
help with the recovery were Maarten Schmidt, who gave up some of his time
(scheduled for work on quasars). James Westphal and James Gunn were
essential in making the CCD system work. Barbara Zimmerman provided
software expertise. Finally, the ephemeris by Donald Yeomans was also
essential.
Prior to the actual recovery of P/Halley, numerous attempts were made
over a five-year period starting in 1977. Early efforts of note were those
of M. Belton and H. Butcher at KPNO using the 4-meter telescope with the
cryogenic camera, a CCD mounted in a semi-solid Schmidt camera cooled to
liquid nitrogen temperatures. Part of the difficulty in recovering P/Halley
was the comet's location close to the galactic plane with densely populated
Milky Way fields.
With the long term future in mind, it is conceivable that this past
apparition of P/Halley was the last this comet was recovered as such. With
the advent of larger ground-based and space-based telescopes, P/Halley may
never be lost again as it heads out to aphelion beyond the orbit of Neptune.
Even the early spectroscopic observations of P/Halley were hampered by
the comet being located in rich Milky Way fields from October 1983 till
February 1985. All spectra of the comet acquired prior to February 1985
were obtained using blind offsets with the slit oriented along the position
angle of the predicted track of the comet. Precise coordinates, determined
to an accuracy of 0.3 arcsec, were determined using SAO stars and from them
secondary astrometric standards were established. Then, using blind offsets
from these secondary standards, the slit was positioned and rotated to the
proper position angle. For each observation on a given night, about a day's
work was involved in setting up the astrometric standards, which were measure
from glass copies of the National Geographic Society-Palomar Sky Survey (1955
edition). In the case of the Kitt Peak National Observatory's 4-meter spectra
a slit width of 3 arcsec and a slit length of 4.5 arcmin was employed.
5. SPECTRA ON THE INBOUND JOURNEY: HELIOCENTRIC DISTANCES FROM 7 TO 4 AU
The Spectroscopy Network was also responsible as a kind of catalyst to
help observers acquire key data sets in the course of the eight years centere
on the 1986 apparition of Comet Halley. In this Halley campaign, the first
phase of spectroscopic observations can be described as pre-sublimation phase
during 1983-1984. The level of detection was so faint in these years (total
magnitude fainter than 23) that no well-defined color or color index could be
derived prior to early 1985, when sublimation had begun. During most of the
preperihelion phase (1982-85) P/Halley was located in a relatively crowded
Milky Way field making it difficult to acquire the comet and obtain reliable
spectra at very low light levels.
The first non-spectroscopic evidence of the developing coma were CCD
images obtained on September 27, 1984 by S.G. Djorgovski and H. Spinrad using
the KPNO 4-meter telescope. A 6 arcsec coma was detected in the red region
(6000-7000 A). Subsequently, in November 1984 A. Crotz acquired additional
CCD images with the KPNO 4-meter showing a similarly extended coma. Spectra
obtained during the period October 1984-January 1985 showed no
spectroscopically detectable emission features. Some observations,
particularly in the U.S.A., were hampered by cloudy weather during this
period. However, the increasing intrinsic light of the comet was the first
evidence of a developing coma.
Low resolution spectra (12-15 A) during this period were obtained by a
team at Kitt Peak National Observatory (M. Belton, H. Spinrad, P. Wehinger,
and S. Wyckoff) using the 4-meter telescope with a grism spectrograph and
CCD. All the observations during 1983-1984 were acquired using blind offsets
from stars near the comet's predicted track with the slit oriented along the
comet's track on the sky and the telescope tracking at the comet's rate in
right ascension and declination. During these years the total light of the
comet was fainter than magnitude 22. These low signal-to-noise spectra,
which showed a reflected solar continuum, were acquired between October 1983
and March 1984. None of the 1983-84 spectra showed any emission features
that would have been indicative of the comet's gas production. Spectra of
P/Halley obtained in October 1984 were collapsed to one-dimension. The
cross-cut spectra first appeared to show evidence suggestive of an extended
coma. However, later very careful astrometry by Belton showed that the "coma
was due to faint Milky Way field stars. The early interpretation suggesting
a developing coma was reported by Belton (1985, Science 230, 1129) in his
review, "Comet Halley: the Quintessential Comet". Thus, in the future, one
should be cautious of early detection of the coma, unless, of course, in situ
measurements are made from a spacecraft.
By February 17, 1985 the first spectroscopic evidence for the onset of
sublimation was detected, by Spinrad observing with the KPNO 4-meter telescop
and by Wyckoff observing with the 4.5-m Multiple-Mirror Telescope (MMT).
Spinrad observed the [O I] 6300 A line (cf. Belton 1985, Science 230, 1129),
while Wyckoff et al. (1985, Nature 316, 241) detected the CN(0,0) violet
system at 3880 A. Barker, Cochran, and Cochran at the McDonald Observatory
detected CN with the 2.7-meter reflector on the same night.
Later, on August 23, 1985, Spinrad detected the C2 Swan system using
the Lick Observatory 3-meter telescope. On October 17-20, 1985 E.M. Burbidge
at Lick, S. Wyckoff at the MMT, and B. Peterson at the Anglo-Australian
Telescope all detected the H2O+ (8,0) vibronic band, while the comet was
2.2 AU from the Sun, nearly twice as distant as any previous H2O+ detection
in a comet.
6. SPECTRA ON THE OUTBOUND JOURNEY: HELIOCENTRIC DISTANCES FROM 4 TO 8 AU
On the outbound journey, the last emission band detections were those of
CN(0,0) and C3 (4040 A) on January 30, 1987 at 5.0 AU by Belton and Wehinger,
who used the Cerro Tololo Interamerican Observatory 4-meter telescope. The
outbound production rates were 15 times greater that the inbound rates. The
extent of the coma from the long slit spectra obtained by Belton and Wehinger
was 32 arcsec in diameter. Other evidence for the apparent inertia in the
comet's outgassing processes were also evident, for example, the CCD imaging
data acquired by R.M. West and his team at the European Southern Observatory.
Attempts to detect the last emission due to the CN violet system were made in
February 1988 by S. Tegler, S. Wyckoff, and P. Wehinger using the KPNO 2.2
meter telescope. Only a scattered solar continuum was detected. West found
coma of more than 30 arcsec in diameter in April 1887 and more than 10 arcsec
in January 1988 at 10.1 AU. Finally, in February 1990, West (IAU Circ. 5059
reported no detectable coma in the visible at a level of 29 mag/arcsec sq.
Table II. Major Spectroscopic Developments as a Function of
time and heliocentric distance r
_______________________________________________________________
r = 8-5 AU Extended dust continuum develops (1984)
r = 6.5 AU Photometric detection of development of coma
(1984)
r = 4.8-4.5 AU Onset of sublimation in CN(0,0) 3883, C3 4040,
[OI] 6300 (February-April 1985)
r = 4.2-2.6 AU Comet lost in Sun's glare, inbound (May-July
1985)
r = 2.4 AU Neutral coma develops, C2 Swan system (August
-September 1985)
r = 2.2 AU H2O+ plasma tail detected (October-November
1985)
r = 1.2-0.8 AU Brightest preperihelion phase (January 1986)
r < 0.7 AU Comet lost in Sun's glare
r = 0.5 AU Comet reaches perihelion (February 9, 1986)
r = 0.8-1.0 AU Brightest post-perihelion phase, spacecraft
encounters (March 6-14, 1986): VEGA-1, VEGA-2,
Suisei, Sakigate, Giotto, ICE
r = 1.2 AU Highest spectral resolution spectra acquired
of neutral species: CN(0,0) R-branch, C2(1,0),
and C2(0,0) rotational lines. Identification
of C{13}N{14} in CN(0,0) violet system R-branch
lines (April 4-7, 1986)
r = 1.4 AU Highest signal-to-noise spectra of the plasma
tail were acquired (April 12-15, 1986) with the
CTIO 4-meter telescope
r = 2.46 AU Neutral molecular spectrum continues (June 30,
1986)
r = 2.5-4.4 AU Comet lost in Sun's glare, outbound journey
(July-October 1986)
r = 4.5 AU Neutral coma continues (December 1986)
r = 4.8 AU Neutral molecular species still detected,
including CN(0,0), C3 4040, and very weak C2
Swan system (January 30, 1987). CN band
strength 15 times greater than at 4.8 AU
pre-perihelion
r = 6.5 AU Dust continuum 32 arcsec diameter detected
spectroscopically (February 1988), no emission
features
r = 10.5 AU Imaging shows continued existence of dust coma,
20 arcsec diameter (May 1989)
r = 12.5 AU Imaging shows no further evidence of coma down
to 29 mag/arcsec sq. (Feb 21-24, 1990)
_______________________________________________________________
7. COORDINATION AND COMMUNICATIONS
At the start of the IHW campaign, communications were limited to
telephone telex, and air mail. By 1985 electronic mail was first becoming
available to more than half of the observers, and by the end of the campaign
(1989), more than ninety percent of the observers had access to some form of
electronic mail. During the period April 1985 to early 1987, an electronic
bulletin board was operated for the IHW at Arizona State University. By
October 1985 the Halley Hotline was linked to GTE's Telenet, the largest
public data network in the United States. Observers could leave messages and
read current updates in five subdirectories, including: spectrophotometry,
imaging, astrometry, space missions, and ephemerides.
From November 1985 to June 1986, some 3000 log-ons were rewcorded by
observers, space scientists, laboratory spectroscopists, and other interested
parties, representing 22 states in the United States, and 12 other countries.
Access within the United States was kindly provided by a corporate gift of
GTE Telecommunications, who provided free access to Telenet. Overseas users
paid the transoceanic charges through their countries post, telephone, and
telex companies to access the Halley Hotline. International users included:
United Kingdom, France, Federal Republic of Germany, the Netherlands, Belgium
Italy, Spain, Austria, Canada, Japan, Chile, and Australia.
8. REMARKS ABOUT GLOBAL COMMUNICATIONS
From a historical perspective, the period 1982-1990 was a time of major
technological advancement with regard to digital computers, local and wide
area computer networks, and national and global computer links. When the IHW
began, we used the conventional postal system, the telephone, and the telex.
The telex provided the widest possible link for communications, though it was
slow and sometimes unreliable in some countries, and was not available in
others. Sometimes no replies came through for months after a telex had been
sent.
In terms of the technology of our times, the common modes of
communication from 1982-85 included airmail (2-15 days in transit),
international telex (immediate, 110 baud) used to most countries but not
widely used in the United States, and telephone (immediate, voice
communication, expensive). By 1985 electronic mail via Bitnet was coming int
use. Bitnet, a system of store and forward from computer to computer, was
promoted by IBM including IBM's support of a trans-Atlantic link from the
United States to Western Europe. This first electronic mail system was free
to the user and grew rapidly. The typical transit time, for example, for a
one page letter from Arizona to France, was 2-3 minutes when all intermediate
nodes were operating, and longer at times of heavy traffic.
At the same time, the Committee Consultatif International de Telex et
Telephone (CCITT) had already set up the X.25 standards for transferring ASCI
files over international telephone networks. The X.25 protocol uses a mode o
packet assembly and disassembly (PAD) software which enables files to be
transferred in a machine-independent manner at a rate of 9600 baud with error
checking routines. GTE Telenet Corporation, which operated the largest
public-data network in the United States in 1985-86, used X.25 protocol for
the transfer of files, for remote log-ons, and for links to international
communications networks. The X.25 protocol provided a much faster and direct
link from node to node, in contrast to the slower store and forward system of
Bitnet.
9. SPECTROSCOPIC DATA: MAGNETIC STORAGE MEDIA
When the first IHW General Meeting was held in August 1982 in Patras,
Greece, in conjunction with the IAU General Assembly, some members of the
IHW Steering Committee expressed concern that a significant percentage of
the spectroscopic data would be recorded on photographic plates and would
require subsequent digital scanning with a microdensitometer. Our early
estimates were that the majority (70-80%) of the spectra would be recorded
in digital format. In fact, virtually all the spectroscopic data that we
received were in digital format. A small percentage (less than 3%) of
spectra originally recorded on photographic plates were scanned with digital
microphotometers by observers at their institutes and were submitted on
magnetic tape. At the time the IHW was organized, photographic plates were
already on their way out. Nearly all observatories that had instrumentation
to record useful slit spectra of comet Halley had some kind of digital
detector system.
10. FITS FORMAT
In order to standardize the data documentation and calibration, we
provided observers with: (1) detailed flux standard star calibration data
using existing compilations by K. Strom from the Kitt Peak National
Observatory; (2) with guidelines to creating FITS (flexible image transport
system) headers, based on the FITS definitions established by Wells, Greisen,
and Harten (1981, Astron. Astrophys., Suppl. Ser. 44, 363), and by Greisen an
Harten (1981, Astron. Astrophys., Suppl. Ser., 44, 371). The initial
motivation for creating FITS formatted data tapes was driven by radio
astronomers, who wished to intercompare and/or combine data sets obtained wit
different radio telescopes. The IHW disciplines have introduced additional
FITS keywords to describe various aspect of their data so that the archive
could be properly documented. Efforts have been made to coordinate common
keywords between various disciplines. During the 1980s FITS format became an
international standard used by ultraviolet, optical, infrared, and radio
astronomers. In addition, public domain data reduction and data analysis
packages, such as IRAF, STSDAS, AIPS, and MIDAS have been designed and writte
to handle data written in FITS format.
The FITS standards were initially established to read and write data on
magnetic tape in machine-independent format. Since then various types of
more compact data-storage media have been developed. The medium selected
for recording the IHW archive is on 5.25-inch diameter compact disks with
read-only-memory (CD-ROM). FITS standards have been modified to handle data
recorded on CD-ROMs. Each CD-ROM holds approximately 650 magabytes. With th
advent of CD-ROMs, another very similar machine-independent formatting system
was established, called PDS for Planetary Data System, by space scientists wh
are primarily involved in the collection and archiving of spacecraft data on
missions within the solar system. Subsequently, routines have been written t
convert data from FITS to PDS and from PDS to FITS format for use with
different software packages and with different applications.
11. SSN FITS KEYWORDS
Below is a description of the keywords used in the FITS headers of the
data from the International Halley Watch Spectroscopy and Spectrophotometry
Network (IHW SSN). Each keyword is listed in capital letters, followed by
an initial, indicating whether the variable is a logical (L), integer (I),
floating point (F), or character string (C).
For several FITS keywords, there are several forms of the keyword,
usually relating to various axes. In these cases, the keyword is listed as
XXXXn, where n is the number of the axis which the keyword describes.
o SIMPLE -L- Does the file conform to the FITS format? If yes,
the keyword is set to T. Otherwise the keyword is F. This
keyword should be set to true for all SSN files.
o BITPIX -I- Keyword contains the number of bits in each
picture element. This value is either 16 or 32 for SSN data.
o NAXIS -I- Keyword contains the number of axes in the data.
One dimensional spectra have a value of 1. Two dimensional
spectra a value of 2.
o NAXISn -I- n is a number in the range of 1 to NAXIS. Keyword
contains the length of axis. NAXIS1 is the dimension of the
fastest varying axis in the data. NAXIS2 is the second
fastest varying axis, etc.
o EXTEND -L- Does the file contain extensions conforming to the
FITS standards? If yes, the keyword is set to T. Otherwise
the keyword is F. For all SSN data files, EXTEND=F.
o OBJECT -C- Keyword contains the name of the object of the
data.
o FILE-NUM -I- This is a running number of the files sent to
the archive. All values have six places and, for the SSN,
begin with 7. For P/Halley, file numbers are in the range of
701000 to 709999.
o DATE-OBS -C- Universal Time (UT) date of middle of data
acquisition. Date is given in the FITS standard of day,
month, year (DD/MM/YY).
o TIME-OBS -F- Fractional part of day, indicating the UT time
of the middle of data acquisition. The keyword has a value
ranging from 0.0 to 0.99999.
o DATE-REL -C- Date the submitter or submitters agree to
release their data to the public.
o DISCIPLN -C- IHW Discipline. For the SSN the value is always
SPECTROSCOPY.
o LONG-OBS -C- East Longitude of observation station. Keyword
value range is from 00/00/00 to 359/59/59.
o LAT--OBS -C- Latitude of observation station. Degrees north
or south are indicated by a preceding '+' or '-',
respectively, 0 degrees has no sign.
o SYSTEM -C- Station system code. Keyword is a number of the
form 7nnnttii where
7- Discipline number (SSN)
nnn- IAU Observatory Number
tt- Telescope Number, as assigned by the IHW Large Scale
Phenomena Network (LSPN)
ii- Instrument/Detector Number, assigned by the SSN, and
corresponds to DD in DIS-CODE keyword
o OBSERVER -C- Name of observer. If more than two observers,
first observer listed, followed by ET AL. Additional
observers are listed in COMMENT ADD.OBS. keyword.
o SUBMITTR -C- Name of the person or persons who submitted the
data to the IHW-SSN.
o SPEC-EVT -L- If true, some special event occurred during
observation. See COMMENTs and HISTORYs for more information.
o DAT-FORM -C- Form of the data. One of: ASCII, STANDARD,
HARDCOPY, NODATA.
o DAT-TYPE -C- Type of data being submitted. One of: UNKNOWN,
REDUCED DIGITAL, RAW DIGITAL, PHOTOGRAPHIC, OBJECTIVE PRISM,
INTERFEROMETRIC, SPACE BORNE.
o DIS-CODE -C- This keyword contains a 9 digit integer with the
digits defined as DDCCWWWRQ where:
DD - Detector/Instrument combination. This is a unique
number for each combination and has been assigned by
the SSN. This value is the same as ii in the SYSTEM
code.
CC - Configuration (grating, grating tilt, filter, aper-
ture size, order, etc.) for a given telescope and
detector/instrument combination.
WWW- Wavelength range in Angstroms, included in the data.
A binary coding scheme is used to specify a unique
number for a unique set of wavelength regions. The
number is the sum of all defined values for each
spectral region in which data is submitted:
1 = <3000
2 = 3000-3499
4 = 3500-3999
8 = 4000-4999
16 = 5000-5999
32 = 6000-6999
64 = 7000-7999
128 = 8000-10000
256 = >10000
Example: Range of 3700-6400 A would be 4+8+16+32=60.
R - Resolution. This parameter is based on the spectral
resolution (FWHM in Angstroms).
1 = <= 0.05
2 = > 0.05 - 0.2
3 = > 0.2 - 1
4 = > 1 - 5
5 = > 5 - 10
6 = > 10 - 20
7 = > 20 - 50
8 = > 50 - 100
9 = > 100
Q - Quality of the data. We adopted a qualitative judge-
ment for this parameter, and the values are the same
as the QUALITY keyword.
0 = Unknown
1 = Excellent
2 = Very Good
3 = Good
4 = Fair
5 = Poor
o OBSVTORY -C- Name of the observatory from which data were obtained.
o ELEV-OBS -F- Elevation of the observing station (meters).
o TELESCOP -C- Telescope used for observation. Where possible,
the telescope name as listed by the Astronomical Almanac has
been used.
o INSTRUME -C- Instrument and detector used for obtaining data.
o RESOL-SP -C- Approximate spectral resolution of data (Ang-
stroms).
o RANGE-SP -C- Approximate spectral range of data (Angstroms).
o EXPOSURE -F- Exposure or integration time (seconds).
o APERSIZE -C- Entrance aperture size, or slit width and length
of instrument or detector (arcsec).
o Airmass -F- One of the following:
AIRM-BEG - Airmass at beginning of observation.
AIRM-END - Airmass at end of observation.
AIRM-MID - Airmass at midpoint of observation.
AIRM-AVE - Average of airmass of observation.
o SEPNUC -F- Separation between the comet nucleus and center of
slit or aperture (arcsec); see figure below.
o ORIENT -F- Position angle of slit or aperture center with
respect to the comet nucleus, measured north through east
(degrees), ranging from 0 to 360 degrees; see figure below.
o POSANG -F- Position angle of slit measured from north through
east (degree), ranging from 0 to 360 degrees. Two dimensional
spectra only. See COMMENT and HISTORY sections for observers'
variations of this definition.
o PIXSCALE -F- Image scale at detector in arcsec per pixel. Two
dimensional spectra only.
o QUALITY -I- A subjective, qualitative estimate of the data.
Values used: UNKNOWN, EXCELLENT, VERY GOOD, GOOD, FAIR, and
POOR.
o CTYPEn -C- n is a number between 1 and NAXIS. Name of the in-
dependent variables:
LAMBDAA - Wavelength (Angstroms).
VELOCITY - Velocity (km/sec).
PIXELS - Pixel number.
RHO - Projected distance (arcsec).
OTHER - Described in a comment.
o BUNIT -C- Name of dependant variable:
FLAMBDA - Flux per wavelength (erg/cm2/s/A).
FNU - Flux per frequency (erg/cm2/s/Hz).
RAYLAMBDA - Flux per wavelength (Rayleighs/A).
RELINS - Relative intensity.
COUNTS - Counts or count rate (counts/second).
DENSITY - Photographic density.
OTHER - Described in a comment.
o CRVALn -F- Reference point for CTYPEn.
o CRPIXn -F- Reference pixel location corresponding to CRVALn.
o CDELTn -F- Increment in CTYPEn per pixel.
o HISTORY DATE-REC -C- Date on which file was received by the
IHW SSN.
o HISTORY DATE-CMP -C- Date on which file archiving had been
completed.
o HISTORY REDUCED -C- Known data reduction steps.
o HISTORY -C- Other history if known.
o COMMENT ADD.OBS. -C- Additional observers.
o COMMENT NOTE -C- Some important note on the data extracted
from COMMENT or HISTORY fields which will appear in the
printed archive listing.
o COMMENT PROC FILE and ORIG. FILE -C- Comment regarding
original file identification of the submitted file. Often
file name consists of position of file on original submission
tape. Used for SSN archiving.
o COMMENT REPLACE -C- A note that this file supercedes another
file (previous file would have been deleted from the
archive).
o COMMENT -C- Additional comments about the data.
o DATAMAX -F- Maximum value of dependent variable.
o DATAMIN -F- Minimum value of dependent variable.
o BSCALE -F- Scale factor to convert FITS pixel values to true
values. Used to convert FITS data to original data values.
DataValue = BZERO + BSCALE * FileDataValue
o BZERO -F- Offset applied to true pixel values.
o END Signals end of FITS header.
12. SSN OBSERVERS AND SUBMITTERS
The observers and submitters participating in the SSN activities are
presented alphabetically in Table III, while Table IV lists chronologically
the submitted contributions of the spectra and Table V shows a brief
statistical distribution of the contributing countries. The institutional
affiliation given for each observer may be different from the institution
where he/she originally acquired the data. The Royal Greenwich Observatory
has moved from Hailsham, East Sussex, to Cambridge, as of 1989. Some effort
has been made to retain the names of observatories for the western European
languages (French, German, Spanish, Portuguese, and Italian), while other suc
names have been translated into English.
Table III. List of SSN Observers and Submitters
_____________________________________________________________________________
Observer/Submitter Institute (City, State, Country)
_____________________________________________________________________________
M.F. A'Hearn University of Maryland, College Park, MD, U.S.A.
I. Appenzeller Landessternwarte, Heidelberg, F.R.G
C. Arpigny Universite de Liege, Cointe-Ougree, Belgium
E.S. Barker McDonald Observatory, University of Texas, Austin TX,
U.S.A.
J.E. Beckman Universidad de La Laguna, Tenerife, Canary Islands, Spain
M.J.S. Belton National Optical Astronomy Observatories, Tucson, AZ,
U.S.A.
J.H. Black University of Arizona, Tucson, AZ, U.S.A.
G. Branduardi Roque de los Muchachos Observatory, Canary Islands, Spain
M. Brear Roque de los Muchachos Observatory, Canary Islands, Spain
M.W. Buie Space Telescope Science Institute, Baltimore, MD, U.S.A.
E.M. Burbidge University of California, San Diego, CA, U.S.A.
P.S. Butterworth NASA Goddard Space Flight Center, Greenbelt, MD, U.S.A.
L. Castinel European Southern Observatory, La Silla, Chile
M. Chester Pennsylvania State University, University Park, PA, U.S.A.
K.I. Churyumov Kiev State University, Kiev, Goloseevo, U.S.S.R.
K.K. Chuvayev Kiev State University, Kiev, Goloseevo, U.S.S.R.
K. Chuvaev Crimean Astrophysical Observatory, Nauchny, Crimea, USSR
A. Cochran McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
W.D. Cochran McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
C. Corbally Steward Observatory, University of Arizona, Tucson, AZ,
U.S.A.
C. Cosmovici Instituto di Astrofisica Spatiale, Fracasti, Roma, Italy
I. Coulson South African Astronomical Observatory, Observatory,
South Africa
D.P. Cruikshank NASA Ames Research Center, Moffett Field, CA, U.S.A.
A. Danks Applied Research Corporation, Landover, MD, U.S.A.
M.S. Dementyev Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
M. DiSanti University of Arizona, Tucson, AZ, U.S.A.
S. Djorgovski California Institute of Technology, Pasadena, CA, U.S.A.
A.N. Dovgopol Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
T. Encrenaz Observatoire de Paris, Meudon, France
L. Engel Arizona State University, Tempe, AZ, U.S.A.
A.P. Fairall University of Capetown, Rondebosch, South Africa
R. Falciani Osservatorio Astrofisico di Arcetri, Firenze, Italy
D. Faria Observatorio Nacinal, Rio de Janeiro, Brazil
P.D. Feldman Johns Hopkins University, Baltimore, MD, U.S.A.
A.J. Ferro Arizona State University, Tempe, AZ, U.S.A.
M. Festou Observatoire de Besancon, Besancon, France
A.V. Filippenko University of California, Berkeley, CA, U.S.A.
U. Fink University of Arizona, Tucson, AZ, U.S.A.
R. Falciani Bologna University Observatory, Loiano, Italy
R.F. Garrison David Dunlap Observatory, Richmond Hill, Ontario, Canada
R. Gilmozzi Astrophysics Institute, Frascati, Italy
R. Goodrich Lick Observatory, Mt. Hamilton, CA, U.S.A.
D.I. Gorodetsky Kiev State University, Kiev, Goloseevo, U.S.S.R.
J. Green McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
R. Haefner Universitats Sternwarte, Munchen, F.R.G.
D. Harmer Royal Greenwich Observatory, Cambridge, U.K.
J. Harland Lick Observatory, University of California, Mt. Hamilton,
CA, U.S.A.
G.H. Herbig University of Hawaii, Honolulu, HI, U.S.A.
S. Ibadov Institute of Astrophysics, Dushanbe, U.S.S.R.
W. Jaworski University of Victoria, Victoria, British Columbia, Canada
V. Jesipov Institute of Astrophysics, Duschanbe, USSR
D. Jewitt University of Hawaii, Honolulu, HI, U.S.A.
M. Kane Goddard Space Flight Center, College Park, MD, U.S.A.
P. Kelton McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
M. Kidger Universidad de La Laguna, Tenerife, Canary Islands, Spain
D. Kilkenny South African Astronomical Observatory, South Africa
V.M. Klimenko Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
P.P. Korsun Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
S. Koutchmy National Solar Observatory, Sunspot, NM, U.S.A.
P.L. Lamy Laboratoire d'Astronomie Spatiale, Marseille, France
S.J. Codina-
Landaberry Observatorio Nacional, Sao Cristouao, Rio de Janeiro,
Brazil
R. Las Casas Observatorio Nacional, Sao Cristouao, Rio de Janeiro,
Brazil
E. Lindholm Arizona State University, Tempe, AZ, U.S.A.
T. Lloyd-Evans South African Astronomical Observatory, Observatory,
South Africa
G. Loper Arizona State University, Tempe, AZ, U.S.A.
B.L. Lutz Lowell Observatory, Flagstaff, AZ, U.S.A.
P. Mack McGraw-Hill Observatory, c/o NOAO, Tucson, AZ, U.S.A.
L. MacFadden University of Maryland, College Park, MD, U.S.A.
K. Magee-Sauer University of Delaware, Newark, DE, U.S.A.
P. Malburet European Southern Observatory, LA Silla, Chile
C. Malivoir Observatoire de Haute-Provence, St. Michel de
l'Observatoire, France
M. Malkan University of California, Los Angeles, CA. U.S.A.
O. Mamadov Institute of Astrophysics, Dushanbe, U.S.S.R.
J. Manfroid Universite de Liege, Liege, Belgium
F. Marang South African Astronomical Observatory, Observatory,
South Africa
R. Marcialis Lunar and Planetary Laboratory, University of Arizona,
Tucson, AZ, U.S.A.
R. Martin Royal Greenwich Observatory, Cambridge, U.K.
Y. Matsuguchi Okayama Astrophysical Observatory, Japan
M. Matsumura Okayama Astrophysical Observatory, Japan
P. McCarthy University of California, Berkeley, CA, U.S.A.
J.S. Miller Lick Observatory, University of California, Santa Cruz,
CA, U.S.A.
A. Miyashita National Astronomical Observatory, Mitaka-Shi, Tokyo,
Japan
Muers Roque de los Muchachos, Canary Islands, Spain
P. Murdin Royal Greenwich Observatory, Cambridge, U.K.
C. Nitscheim Observatoire de Haute-Provence, St. Michel de
l'Observatoire, France
C.R. O'Dell Rice University, Houston, TX, U.S.A.
R. Oliversen Kitt Peak National Observatory, Tucson, AZ, U.S.A.
C. Opal McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
J. Pacheco Observatorio Ncaional, Rio de Janeiro, Brazil
P. Patriarchi Osservatorio Astrofisico di Arcetri, Firenze, Italy
B. Peterson Mount Stromlo & Siding Spring Observatories, Canberra, ACT
Austral ia
M. Prieto Roque de los Muchachos, Canary Islands, Spain
D.A. Ramsay National Research Council of Canada, Ottawa, Ontario,
Canada
L. Ramsey Pennsylvania State University, University Park, PA, U.S.A.
N. Reid Roque de los Muchachos, Canary Islands, Spain
R.J. Reynolds University of Wisconsin, Madison, WI, U.S.A.
F. Roesler University of Wisconsin, Madison, WI, U.S.A.
E. Roettger Johns Hopkins University, Baltimore, MD, U.S.A.
T. Santos Observatorio Nacional, Rio de Janeiro, Brazil
W. Sargent Palomar Observatory, California Institute of Technology,
Pasadena, CA, U.S.A.
S. Sawyer McDonald Observatory, University of Texas, Austin, TX,
U.S.A.
F. Scherb University of Wisconsin, Madison, WI, U.S.A.
D.G. Schleicher Lowell Observatory, Flagstaff, AZ, U.S.A.
A. Schultz Lunar and Planetary Laboratory, University of Arizona,
Tucson, AZ, U.S.A.
V. Shavlovski Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
K.R. Sivaraman Indian Institite of Astrophysics, Bangalore, India
L.A. Smaldone Dipartimento di Fisica, Napoli, Italy
H. Spinrad University of California, Berkeley, CA, U.S.A.
M. Strauss University of California, Berkeley, CA, U.S.A.
M. Takada-Hadai Tokai University, Hiratsuka-Shi, Kanagawa, Japan
H. Tanabe National Astronomical Observatory, Mitaka-Shi, Tokyo, Japa
Y. Taniguchi Kiso Observatory, Kiso-Gun, Nagano-Ken, Japan
V.P. Tarashchuk Kiev State University, Kiev, Goloseevo, U.S.S.R.
J.B. Tatum University of Victoria, Victoria, British Columbia, Canada
S. Tegler University of Florida, Gainesville, FL, U.S.A.
R. Terlevich Royal Greenwich Observatory, Cambridge, U.K.
J. Theobald Arizona State University, Tempe, AZ, U.S.A.
G.P. Tozzi Osservatorio Astrofisico di Arcetri, Firenze, Italy
S. Unger Royal Greenwich Observatory, Cambridge, U.K.
W. van Breugel University of California, Berkeley, CA, U.S.A.
C. Vanderriest Observatoire de Paris, Meudon, France
R.M. Wagner Lowell Observatory, Flagstaff, AZ, U.S.A.
M. Wallis University College Cardiff, Wales, U.K.
J. Watanabe Tokyo National Observatory, Tokyo, Japan
H. Weaver Space Telescope Science Institute, Baltimore, MD, U.S.A.
P.A. Wehinger Arizona State University, Tempe, AZ, U.S.A.
M. Womack Arizona State University, Tempe, AZ, U.S.A.
T. Woods Johns Hopkins University, Baltimore, CA, U.S.A.
Wu Guangjie Yunnan Observatory, Kunming, China
S. Wyckoff Arizona State University, Tempe, AZ, U.S.A.
F. Wyk South African Astronomical Observatory, Observatory,
South Africa
Y.S. Yatskiv Main Astronomical Observatory, Kiev, Goloseevo, U.S.S.R.
D.K. Yeomans Jet Propulsion Laboratory, Pasadena, CA, U.S.A.
J.-M. Zucconi Observatoire de Besancon, Besancon, France
_____________________________________________________________________________
Table IV. Contributed Comet Halley Spectra
____________________________________________________________________
Submitter State/Country No. Date Observatory
Spectra Received
____________________________________________________________________
Wehinger, P Arizona, USA 13 15 Jun 87 AAT
Herbig, G California, USA 134 22 Jun 87 Lick
Tatum, J B.C., Canada 222 10 Sep 87 AAT
O'Dell, C Texas, USA 35 02 Nov 87 CTIO
Spinrad, H California, USA 44 06 Nov 87 Lick
Festou, M France 38 09 Nov 87 IUE
Tegler, S Arizona, USA 1 30 Nov 87 CTIO
Buie, M Hawaii, USA 5 03 Dec 87 MKO
Jewitt, D Mass, USA 139 07 Dec 87 KPNO
Haefner, R Germany 9 21 Dec 87 ESO
Magee, K Wisconsin, USA 383 25 Feb 88 KPNO
Appenzeller, I Germany 5 04 Mar 88 ESO
Ramsay, D Ontario, Canada 81 15 Mar 88 AAT
Takada-Hidai, M Japan 36 05 Apr 88 Okayama
Mack, P South Africa 15 06 Apr 88 SAAO
Magee, K Wisconsin, USA 96 22 Apr 88 KPNO
Tozzi, G-P Italy 39 25 Apr 88 ESO
Filippenko, A California, USA 39 25 May 88 Palomar
Korsun, P Urkaine, USSR 7 25 May 88 Kiev
Garrison, R Ontario, Canada 33 31 May 88 LCO
Taniguchi, Y Japan 3 31 May 88 Okayama
Koutchmy, S France 2 09 Jun 88 ESO
Chester, M Penn, USA 15 21 Jun 88 Penn St
Landaberry, S Brazil 12 23 Jun 88 Obs Nat Brazil
Cochran, A Texas, USA 558 27 Jun 88 McDonald
Cochran, A Texas, USA 76 14 Jul 88 McDonald
Tanabe, H Japan 8 03 Aug 88 Tokyo Astr
Lamy, P France 14 03 Aug 88 ESO
Engel, L Arizona, USA 18 01 Sep 88 KPNO
Lindholm, E Arizona, USA 17 01 Sep 88 Mt Stromlo
Lindholm, E Arizona, USA 18 07 Sep 88 Mt Stromlo
Theobald, J Arizona, USA 13 04 Oct 88 AAT
Festou, M France 350 07 Nov 88 IUE
Encrenaz, T France 70 07 Nov 88 ESO
Sivaraman, K R India 16 22 Nov 88 Bappu Obs
Martin, R United Kingdom 116 28 Nov 88 La Palma
Peterson, B Australia 60 02 Dec 88 AAT
Tegler, S Arizona, USA 7 19 Dec 88 CTIO
Kidger, M Spain 48 28 Dec 88 La Palma
Belton, M Arizona, USA 19 04 Jan 89 KPNO
Feldman, P Maryland, USA 4 04 Jan 89 Rocket
Womack, M Arizona, USA 7 30 Jan 89 AAT
Wagner, M Arizona, USA 76 06 Feb 89 Lowell
Womack, M Arizona, USA 4 20 Feb 89 AAT
Festou, M France 152 08 Mar 89 IUE
Wehinger, P Arizona, USA 6 09 Mar 89 CTIO
Yatskiv, Y Urkaine, USSR 259 14 Mar 89 Kiev
Wu, G P.R. China 6 22 Mar 89 Yunnan
Zucconi, J-M France 15 28 Mar 89 OHP
Festou, M France 264 10 Apr 89 IUE
Total 3500 (140% of expected submissions)
____________________________________________________________________
Table V. Worldwide Distribution of
Halley Spectroscopic Contributions
____________________________________
Australia Spain
Belgium United Kingdom
Brazil United States
Canada Arizona
Chile California
China, P.R. Hawaii
France Maryland
Germany Massachusetts
India New Mexico
Italy Pennsylvania
Japan Texas
South Africa Wisconsin
Soviet Union
____________________________________
13. SPECTROSCOPIC SOLAR ATLASES
Two high resolution integrated disk solar spectra compiled from a variet
of sources are presented in this archive. One was contributed by M. A'Hearn
and the other by R. Kurucz. The A'Hearn solar spectrum found in one file,
SOLATLS1.FIT, is given in vacuum wavelengths (Angstroms), calibrated in flux
units (erg/cm**2/s/A) covering the wavelength range 2245 A to 7000 A in steps
of 0.005 A. The Kurucz solar spectrum can be found in two files, SOLATLS2.FI
and SOLATLS3.FIT, in air wavelengths (Angstroms), calibrated in flux units
(erg/cm**2/s/A). SOLATLS2.FIT covers a wavelength range 2960 A to 8000 A in
steps of 0.005 A, SOLATLS3.FIT covers the wavelength range of 8000 A to 13,00
A in steps of 0.01 A. We note a wavelength shift between the two solar
spectra presented in this archive of approximately 0.03 A in the sense A'Hear
minus Kurucz. We therefore caution users of these files requiring wavelength
accuracies better than this difference to first assess and correct the wave-
lengths the solar spectra to rest frame.
14. REFERENCES ON COMETARY SPECTROSCOPY
Listed below are a few key review papers on cometary physics and
spectroscopy that may serve as an introduction for interested observers
who are just getting started in the field. These references are simply
listed as a guide and a starting point for future investigators.
1. A'Hearn, M.F. 1982. Spectrophotometry of comets at optical wavelengths.
In: Wilkening, L.L. (ed.), Comets, Tucson: University of Arizona Press,
pp. 433-460.
2. A'Hearn, M.F. 1988. Observations of comet nuclei. Ann. Rev. Earth
Planet. Sci. 16, 273-293.
3. Feldman, P.D. 1982. Ultraviolet spectroscopy of comets. In: Wilkening,
L.L. (ed.), Comets, Tucson: University of Arizona Press, pp. 461-479.
4. Grewing, M., Praderie, F., and Reinhard, R. (eds.) 1988. Exploration of
Halley's Comet, Berlin: Springer, pp. 1-984; see also Astron. Astrophys.
187, 1-936 (1987).
5. Huebner, W.F. 1985. The photochemistry of comets. In: The Photo-
chemistry of Atmospheres, Earth, the Other Planets and Comets, New York:
Academic Press, pp. 437-508.
6. Krishna Swamy, K.S. 1986. Physics of Comets, Singapore: Worls
Scientific Publishing Company.
7. Mendis, D.A. 1988. A post-encounter view of comets. Ann. Rev. Astron.
Astrophys. 26, 11-49.
8. Mendis, D.A., Houpis, H.L.F., and Marconi, M.L. 1985. The Physics of
Comets. Fundamentals of Cosmic Physics 10, 1-353.
9. Spinrad, H. 1987. Comets and their composition. Ann. Rev. Astron.
Astrophys. 25, 231-269.
10. Whipple, F.L., and Huebner, W.F. 1976. Physical Processes in Comets.
Ann. Rev. Astron. Astrophys. 14, 143-172.
11. Wyckoff, S. 1982. Overview of comet observations. In: Wilkening, L.L.
(ed.), Comets, Tucson: University of Arizona Press, pp.3-55.
12. Wyckoff, S. 1983. Interaction of cometary ices with the Interplanetary
Medium. J. Phys. Chem. 87, 4234-4242.
13. Wyckoff, S. 1990. Comets: clues to the early history of the solar
system. Earth Sci. Rev., in press.
Susan Wyckoff, Anthony J. Ferro, and Peter A. Wehinge
Physics-Astronomy Department
Arizona State University
Tempe, AZ 85281
U.S.A.