RADIO SCIENCE NETWORK
1. INTRODUCTION
Radio Astronomy is a developing new technique for the study of comets.
In some areas, such as observations of the OH radical via its 18 cm
transitions, the observational procedures and analysis are well developed.
Studies in these areas have proved their value since they both provide new
probes of important physical processes as well as a window on physical
processes which are less wellknown and less accessible to study by other
techniques. In many other areas, however, the study of comets at radio
wavelengths continues to be primarily an exploratory endeavor. In recognition
of this fact, the IHW Radio Science Discipline Specialist team (Table I) felt
that it was important to attempt many different kinds of observations during
this campaign on Halley's Comet, since each observation has scientific merit
as an exploration. Thus, we have been careful to document and include all
data submitted to this archive by radio observers.
Table I. Discipline Specialist Team of the Radio Science Network
___________________________________________________________________________
Team Member Affiliation Responsibility
___________________________________________________________________________
William M. Irvine Astronomy Program Discipline Specialist
University of Massachusetts
Amherst, MA 01003
U.S.A.
F. Peter Schloerb Astronomy Program Discipline Specialist
University of Massachusetts
Eric Gerard Departement de Radioastronomie Discipline Specialist
Observatoire de Meudon
F-92190 Meudon
France
Ronald D. Brown Department of Chemistry Discipline Specialist
Monash University 1981-85
Clayton, Victoria 3168
Australia
Peter D. Godfrey Department of Chemistry Discipline Specialist
Monash University 1981-85
Wayne M. Kinzel Astronomy Program Archive Manager
University of Massachusetts
___________________________________________________________________________
1.2 Radio Science Network Summary
The P/Halley Archive contains data from 36 different observing groups,
representing a range of techniques. The majority of the observational data
comes in the well developed area of 18cm OH observations. However, many other
projects were attempted as well. Approximately 75% of the groups who are
known to have obtained useful data on the comet have submitted it to the
archive, and we are grateful to them for their contributions.
In this document, we describe the format of the data contained in the
Radio Science archive of observations of P/Halley. In Sec. 2, we present a
detailed description of the FITS files which contain the data. Section 3
contains a description of the Radio Science Index to the CD-ROM. Section 4
provides a description of the printed archive format, which may also be used
as an index to the data under some circumstances. The units adopted by the
Radio Science Network are given in Sec. 5, and the calibration of data is
discussed in Sec. 6. Finally, in Sec. 7, we acknowledge those who have been
so helpful to us in the construction of this archive.
2. THE RADIO SCIENCE FITS FORMAT
2.1 FITS Header Description
The IHW Radio Science archive is written in FITS format following the
standard for all networks within the IHW. FITS files are a standard for
interchange of astronomical data. They consist of one or more 2880-byte
header records, which contain the documentary information about the
observation, followed by 0 or more 2880-byte data records in the format that
is specified by the FITS header. In the IHW archive, these two parts of a
FITS file, the header records and the data records, are presented in two
different files to facilitate their use by a wide range of analysis software.
However, we note that users who require FITS format files have only to
concatenate the header and data files to make a standard FITS file.
The FITS header is meant to provide a description of the structure and
format of the FITS data records that follow it and to offer any auxiliary
information that is necessary for its interpretation. For the Radio Science
FITS header, we have defined several FITS keywords which specify observational
parameters that are necessary to interpret the data. A detailed description
of the complete Radio Science FITS header is presented in Sec. 2.1. In
general, the Radio Science Network has tried to conform to standards which are
commonly used in FITS and adopted by the IHW. The characteristics of the
observation are described by assigning values to the "keywords" which are
described in the tables below. We note that special keywords which we have
defined have been selected to specify information which is vital to the
interpretation of the data, such as specification of the observing frequncy or
telescope parameters. At another level, under FITS HISTORY keywords, we
present information about how the data were obtained, including calibration
and orbital tracking information. The distinction between these groupings is
admittedly somewhat arbitrary and has been made primarily to limit the number
of new FITS keywords defined by our network.
In an exploratory program, like the Radio Science Network, it is to be
expected that many observations will fail to detect the comet, and the data to
be archived are best described as an upper limit rather than through
presentation of a spectrum or image. In recognition of this fact, the IHW
permits FITS files to be created without any data records at all, and in this
case, the "data" are presented as a summary in the FITS HISTORY section of the
Radio Science header. FITS files of this type may be recognized because they
have the NAXIS keyword set equal to 0 and the DAT-TYPE keyword set equal to
the character string 'NODATA '.
Where possible, even when actual data exist, we have attempted to
describe them by presenting the results of a model fit to the data. In
spectral line work, for example, a line is often described in terms of its
peak intensity, the velocity of the peak, the line width, the integrated area
under the line, and the mean velocity of the emission. We have provided these
values in FITS HISTORY keywords by fitting a gaussian line shape model to the
data.
2.1.1 Keyword block I: Basic FITS keywords
This block of keywords is required of FITS tapes. The details are listed
in Table II below.
Table II. Keyword Block I
______________________________________________________________________________
Keyword Type Description
______________________________________________________________________________
SIMPLE L Conformity to basic FITS standards
BITPIX I Bits per pixel in data record
NAXIS I Number of axes in data record; if NAXIS = 0 then no data record
NAXIS1 I Number of pixels in row along first axis; if NAXIS1 = 0 then
this is Extended FITS Format and GROUP data are present
NAXISn I Number of pixels along n-th axis in image
______________________________________________________________________________
2.1.2 Keyword block II: International Halley Watch keywords
These keywords are agreed upon for use by the entire Halley Watch and
they are listed in Table III.
Table III. Keyword Block II
______________________________________________________________________________
Keyword Type Description
______________________________________________________________________________
OBJECT C Name of the object
Examples: 'P/CROMMELIN'
'P/HALLEY'
'P/GIACOBINI-ZINNER'
FILE-NUM I 6NNNNV - unique, sequential number to identify files sent to
IHW Lead Center. Format description:
6 = denotes Radio Science Network
NNNN = unique 4 digit ID number assigned to each observation
V = version number (used to keep track of resubmissions)
DATE-OBS C 'DD/MM/YY' - UT date of middle of observation
if observations made during several intervals, then these
intervals will be specified in the HISTORY fields
described below
TIME-OBS R UT time of middle of observation expressed in decimal days
DATE-REL C 'DD/MM/YY' - date when observations may be publicly released
DISCIPLN C 'RADIO STUDIES' - the Network identification
LONG-OBS C 'DDD/MM/SS' - east longitude of observatory (0-360 deg)
LAT--OBS C 'sDD/MM/SS' - latitude of observatory
SYSTEM C '6OOOCCTT' - system code formatted:
6 = Radio Science Network
OOO = IAU number for observatory
(OOO = 500 for radio observatories since no IAU number
exists)
CC = identifies country according to LSPN Code
TT = identifies radio telescope
OBSERVER C Name of observer
Format : 'LASTNAME,I' - 1 author
'LASTNAME,I/NEXTNAME,J' - 2 authors
'LASTNAME,I/ET AL.' - >2 authors
For more than 2 observers, the names of all additional
observers are given in special ADD. OBS. comments
SUBMITTR C Name of submitter of data
SPEC-EVT L Flag for special events as designated by Discipline Specialist
DAT-FORM C Describes format of FITS data records
'NODATA ' - no FITS data records written
'STANDARD' - data records conform to FITS standard
'ASCII ' - data records are to be interpreted as logical
records of 80 ASCII characters (not FITS standard)
'HARDCOPY' - data submitted as hardcopy
______________________________________________________________________________
2.1.3 Keyword block III: Radio Science keywords
These keywords are to be directly read by computers in the normal manner
of FITS header keywords. Some attempt has been made to choose keyword names
that are already in use by the astronomical community. These keywords are
used to describe information that is vital to the data interpretation or
potentially useful for searches of the data base (Table IV).
Table IV. Keyword Block III
______________________________________________________________________________
Keyword Type Description
______________________________________________________________________________
DIS-CODE C 'TFESEWEABENC' - describes parameters of the
telescope/instrument
T : Telescope type
S = single antenna
I = interferometer
U = unknown/unclassified
FE: Frequency (Center Frequency or Rest Frequency)
FE=> frequency = F x 10**(E) MHz
00= unknown
SE: Spectral resolution
SE=> spectral resolution = S x 10**(E) Hz
00= unknown
WE: Bandwidth
WE=> bandwidth = W x 10**(E) Hz
00= unknown
A : Beam description
C = circular
E = ellipitical
O = other
U = unknown
BE: Beam size (geometric mean)
BE=> beam size = B x 10**(E) arcsec
00= unknown
N : Noise estimate
N => RMS noise = 10**(N) microJansky/beam
0 = unknown
C : Information provided by observer to Discipline Specialist
is complete
T = TRUE
F = FALSE
DAT-TYPE C 'NNSTHP' - describes the data format in Header and Data Records
NN: Subnetwork
OH= OH Subnetwork
Spectral line observations of 18-cm OH
SL= Spectral Line Subnetwork
Spectral line observations (other than 18-cm OH)
CN= Continuum Subnetwork
Broadband continuum observations
OC= Occultation Subnetwork
Observation of occultation events
RD= Radar Subnetwork
Active experiments
S : Search/detection status
S = search - implies nondetection (< 3 sigma)
D = detection - implies detection (> 3 sigma)
M = marginal - implies marginal detection (approx.
3 sigma)
T : Type of data in FITS Data Records
N = no FITS Data Records
S = Spectrum => intensity vs frequency
C = Continuum scan => intensity vs space
T = Time series => intensity vs time
I = Image => spatial - spatial image
D = Dynamic spectrum => frequency - time image
F = SV image => frequency - spatial image
V = Visibility Function Data
H : Summary of Data in Header?
T = Summary of data exists in Header History Section
F = No summary of data in Header History Section
P : Polarization status
I = Intensity data only
P = Polarization data format used
OBSVTORY C Abbreviation for Observatory.
TELESCOP C Telescope identifier - usually gives aperture size in meters
LOCATION C Location of Observatory as given in American Ephemeris
INSTRUME C 'FRONT/BACK' - describes "frontend" and "backend" of receiver
FRONT: Receiver Front End
MASER = Maser Amplifier
FET = Field Effect Transistor Amplifier
PARA = Parametric Amplifier
MIXER = Mixer
SPEC = Special Front End
UNK = Unknown Front End
BACK : Receiver Back End
FB = Filterbank
SEFB = Filterbank with Spectrum Expander
AC = Autocorrelator
CONT = Broadband Continuum Receiver
SPEC = Special Back End
AOS = Acousto-Optical Spectrometer
UNK = Unknown Back End
CENTFREQ R Center frequency of observed bandwidth (Hz)
BANDWIDT R Total bandwidth (Hz)
BEAMSIZE R Geometric mean of major and minor axes of Elliptical Gaussian
Beam (deg)
BEAMELON R Ratio of major beam axis to minor beam axis
BEAMROTA R Position angle of major beam axis (deg)
BEAMEFF R Beam efficiency - fraction of power received that is in the
Gaussian Main Beam (BEAMEFF = 0.0 if unknown or unspecified)
MOLECULE C Chemical formula for molecule (follows convention of NBS
interstellar-line list)
TRANSITN C Quantum numbers for transition (follows convention of NBS
interstellar-line list)
RESTFREQ R Rest frequency of line used by observer (Hz)
RES-SPEC R Spectral resolution (Hz) - true spectral resolution of the
spectrometer, NOT the channel spacing
EQUINOX R Equinox of RA-DEC information presented in this file
RAOFF R Pointing offset in RA direction DELTA(RA)*COS(DEC) (deg)
DECOFF R Pointing Offset in Dec direction DELTA(DEC) (deg)
DATE-BEG C 'DD/MM/YY' - UT date on which observations began
DATE-END C 'DD/MM/YY' - UT date on which observations ended
______________________________________________________________________________
2.1.4 Keyword Block IV: Special Keywords for Printed Archive
This group of COMMENT lines give additional information to be used in the
production of the IHW printed archive.
The ADD. OBS. comment gives the names of the full observing team in the
case that more than two observers carried out the observations. More than one
ADD. OBS. comment may be used to specify teams with many members or long
names. The format of the ADD. OBS. comment is:
COMMENT ADD. OBS. NAME,I/NAME2,I/NAME3,I
The NOTE comment provides information that is to be printed as a footnote
in the printed archive in the following format:
COMMENT NOTE THIS IS A TEST
2.1.5 Keyword Block V: Radio Science Data History Section
This block of FITS HISTORY keywords is provided to incorporate additional
information about the observation, such as descriptions of calibration methods
and sources, details about observing procedures, and comments by the observer
and the IHW Discipline Specialist. Another important use of the HISTORY lines
is to provide a summary of the data obtained, or in the case of FITS files
with no data records, the actual data values reported by the observer. The
general format of the HISTORY lines is:
column
1 11 21
HISTORY SUBKEY__ VALUES....
where values is a list of values associated with this subkey. In most cases,
the value lists are in a fixed format in order to simplify their use.
2.1.5.1 Data summary section
In order to transmit upper limits or a summary of the data that would be
appropriate for tabular presentation in the printed archive, we utilize one of
the following HISTORY keyword formats. Such summaries of the data will always
be contained in the first part of the HISTORY keyword section; the presence of
such a summary shall be indicated in the DAT-TYPE keyword discussed above. In
the case where FITS data records accompany the header, USERS OF THE ARCHIVE
ARE CAUTIONED THAT THE SUMMARY VALUES ARE ONLY MEANT TO DESCRIBE AND
CHARACTERIZE THE DATA ... NOT TO REPLACE THEM.
All summary lines follow the same general form:
HISTORY SUBKEY ################ 'UNITS '
where the # field is a right justified floating point number.
Format for Upper Limits:
COMMENT *SUMMARY OF DATA - UPPER LIMIT
HISTORY LIMIT 0.5 'JY/BEAM '
Upper limits in the Radio Science Network are always given as 3 standard
deviation upper limits.
Format for Spectral Lines:
COMMENT *SUMMARY OF DATA - SPECTRAL LINE
HISTORY LINEPEAK 0.5 'JY/BEAM '
HISTORY ERR-PEAK 0.1 'JY/BEAM '
HISTORY LINE-VEL 10.0 'M/SEC '
HISTORY ERR--VEL 200.2 'M/SEC '
HISTORY LINE-WID 2532.0 'M/SEC '
HISTORY ERR--WID 130.2 'M/SEC '
HISTORY LINEAREA 1243.1 'JY/B*M/S'
HISTORY ERR-AREA 143.6 'JY/B*M/S'
HISTORY LINEMEAN 32.1 'M/SEC '
HISTORY ERR-MEAN 10.2 'M/SEC '
The spectral line summary values LINEPEAK, LINE-VEL, and LINE-WID are
determined from gaussian fits to the line profiles. If one or more parameters
were fixed in a fit to the data, the assumed values are listed with no errors.
Spectral lines with hyperfine structure (e.g., HCN) are fitted on the
assumption that all hyperfine components have their nominal intensity ratios.
Format for Continuum Observations:
COMMENT *SUMMARY OF DATA - CONTINUUM
HISTORY CONTFLUX 0.5 'JY/BEAM '
HISTORY ERR-FLUX 0.1 'JY/BEAM '
Format for Radar Observations:
COMMENT *SUMMARY OF DATA - RADAR
HISTORY XSECTION 30.0 'SQUARE KILOMETERS'
HISTORY ERR-XSEC 6.0 'SQUARE KILOMETERS'
2.1.5.2 Observing window section
Since many radio observations take place over several days, we include
the precise observing windows in the HISTORY section according to the format:
COMMENT *OBSERVING WINDOW SPECIFICATION
HISTORY N-WINDOW #
HISTORY WINDOW 'DD/MM/YY' ####### 'DD/MM/YY' #######
HISTORY WINDOW 'DD/MM/YY' ####### 'DD/MM/YY' #######
where N-WINDOW gives the total number of windows for observation and
subsequent window lines give the date and time (in decimals as in TIME-OBS) of
beginning and end of the observing window. The time fields are right
justified floating point numbers.
2.1.5.3 Orbital elements section
Radio observers track the comet "blind" and it is important to know
the precise position on the sky that they were tracking. We include a
provision in the HISTORY section to specify the two-body elements and
observatory position data used to produce the topocentric ephemeris for
tracking.
COMMENT *ORBITAL ELEMENT SPECIFICATION
HISTORY ORBELEM T - T if orbital elements are
provided
HISTORY LONGEAST 243.11046715 - east longitude of observatory
(deg)
HISTORY RHO--COS 0.8159113419 - radius*cos(lat) for observatory
(units of Earth equatorial
radius)
HISTORY RHO--SIN 0.5765085118 - radius*sin(lat) for observatory
(units of Earth equatorial
radius)
HISTORY ET-UT 53.18439 - Ephemeris Time - UT correction (s)
HISTORY JD 2446471.16128 - Time of Perihelion passage (ET)
HISTORY Q 0.5870959 - Perihelion Distance (AU)
HISTORY E 0.9672671 - Eccentricity
HISTORY SOMEGA 111.85336 - Arg. of Perihelion (deg)
HISTORY LOMEGA 58.15313 - Long. of Ascending Node (deg)
HISTORY I 162.23779 - Inclination (deg)
2.1.5.4 Antenna tracking section
This HISTORY keyword specifies the antenna rms pointing errors.
COMMENT *RMS POINTING ERROR OF TELESCOPE
HISTORY POINTERR ################ 'UNITS '
2.1.5.5 Calibration section
This group of keywords provides information on details of the calibration
process.
COMMENT *CALIBRATION METHOD INFORMATION
HISTORY CALMETH 'DESCRIPTION OF CAL METHOD'
If the calibration method is unknown, then no line appears. Current possible
values are 'CHOPPER WHEEL', 'NOISE TUBE', 'STANDARDS', 'ABSOLUTE'.
COMMENT *CALIBRATION STANDARD INFORMATION
HISTORY CALSRCE 'SOURCE NAME' ########## 'UNITS '
Source (or sources) used to provide principal calibration. The # field is a
right justified floating point number. For planets as the calibrators, the
assumed brightness temperature is given; otherwise, the calibrator flux
density is given in Jansky. There may be more than one CALSRCE HISTORY line.
COMMENT *SYSTEM TEMPERATURE ETC.
HISTORY TSYSTEM ############### '_SB '
HISTORY TRCVR ############### '_SB '
Total system temperature (TSYSTEM) and noise temperature of the reciver alone
(TRCVR). '_SB ' allows single side band measurement ('SSB ') or
double sideband measurement ('DSB ') to be indicated. The # field is a
right justified floating point number.
HISTORY TAUZENTH ###############
Atmospheric opacity at zenith. The # field is a right justified floating
point number.
2.1.5.6 Observer's comment section
This block of HISTORY lines contains any extra comments about conditions,
data quality, etc. that are sent to the Discipline Specialist by the observer.
There are generally fewer than eight such comment lines given.
COMMENT *OBSERVER COMMENTS
HISTORY OBSCOMM ROOM TO REPORT OBSERVER COMMENTS
HISTORY OBSCOMM ...
HISTORY OBSCOMM ...
HISTORY OBSCOMM MORE ROOM FOR OBSERVER COMMENTS
2.1.5.7 Discipline Specialist's comment section
Comments by the Discipline Specialist team on this observation. There
are generally fewer than eight such comment lines given.
COMMENT *DISCIPLINE SPECIALIST COMMENTS
HISTORY DSCOMM ROOM TO REPORT DISCIPLINE SPECIALIST COMMENTS
HISTORY DSCOMM ...
HISTORY DSCOMM ...
HISTORY DSCOMM MORE ROOM FOR DISCIPLINE SPECIALIST COMMENTS
2.1.6 Keyword block VI: Standard FITS keywords
These keywords are used to describe the FITS data records. They are all
standard and they are summarized in Table V.
Table V. Keyword Block VI
______________________________________________________________________________
Keyword Type Description
______________________________________________________________________________
BSCALE R Scale factor data = tape * BSCALE + BZERO
BZERO R Zero value
BUNIT C Units of data
'JY/BEAM ' - for line and continuum data
'STANDARD DEVIATIONS' - for radar data
BLANK I Value for out-of-range data
CRVALn R Value of physical coordinate of nth axis at the reference pixel
CRPIXn R Array location of reference pixel for nth axis
CDELTn R Increment in physical coordinate along nth axis
CTYPEn C Type of physical coordinate
'VELO-COM' - frequency coordinate for line work in m/s defined
to be velocity relative to the comet
'VELO-GEO' - velocity defined relative to center of Earth
'FREQUENCY' - frequency offset of radar echo from expected
value in units of Hz
'CIRCULAR POLARIZATION' - axis used to define different states
of circular polarization: -1 = LHC;
-2 = RHC
'LINEAR POLARIZATION' - axis used to define linear polarization
position angle
'ECHO POLARIZATION' - axis used to define polarization of radar
echo
'RAOFF ' - spatial coordinate for maps (deg)
'DECOFF ' - spatial coordinate for maps (deg)
'RA ' - coordinate used for drift scans (deg)
'MAP-TYPE' - coordinate to indicate type of drift scan map:
0 = map with comet in beam; 1,2 = maps of galactic
background only
CROTAn R Rotation angle of physical coordinate axis n
______________________________________________________________________________
2.1.7 Keyword block VII: End statement
This keyword is required by FITS to terminate the header:
END
2.2 Types of Data in the P/Halley Archive.
Several distinct types of data were obtained during the International
Halley Watch, and each data type required the use of a slightly different type
of FITS format. In this section, we review the individual data types and any
special steps taken in formatting data of this type.
2.2.1 Upper limits
As stated above in the description of the FITS format, upper limits are
reported in the HISTORY section of the FITS header in the HISTORY LIMIT
keyword. The detection status of a particular observation is summarized in the
third character of the DAT-TYPE keyword. An S implies that the observation
did not yield a detection and is reported as a limit. However, in some cases
marginal results, designated by M in the DAT-TYPE keyword have also been
reported as limits.
2.2.2 OH spectral line observations
The principal type of data is the 18-cm OH observations. These data are
archived in FITS format as one-dimensional spectra of the flux density of the
comet as a function of the line of sight velocity. For most OH observations,
the line of sight velocity is given with respect to the observer, although
some observers transmitted their results to us in terms of the geocentric
velocity.
Many OH line observations were conducted using two receivers having
orthogonal polarizations. In order to preserve this information, we have
presented the polarized spectral data in a two dimensional format with a
second axis to designate which polarization applies. These spectra will have
the NAXIS keyword set equal to 2, and the second axis will be labeled either
'CIRCULAR POLARIZATION' or 'LINEAR POLARIZATION', as shown in Table V above.
This method for designating polarization is similar to the convention used in
many FITS formats, where a separate axis (often labeled 'STOKES') is used to
give the full Stokes parameters of the data. However, full Stokes parameters
have not measured in this archive, and so we have defined these new
polarization axes to handle this situation.
2.2.3 Interferometric UV data
Radio interferometers measure a source's visibility function, which is
the Fourier transform of the source brightness distribution. In aperture
synthesis imaging, a set of measurements of the visibility function are
Fourier transformed to obtain an image of the source brightness distribution.
Unfortunately, the processing steps required to make a map force the observer
to specify many parameters that determine how the visibility data will be
transformed to make the image. The specification of these parameters and the
Fourieer transformation of the data, in our view, constitutes an
interpretation of the data, and runs counter to the philosophy of a data
archive. Thus, we have preserved the actual visibility data in this archive.
The visibility data are presented in the extended FITS GROUP data format.
This is the format currently used for visibility data by many of the world's
interferometers, and FITS readers for visibility data should be able to read
the files prepared for the IHW archive directly. We have tested the files in
the data reduction program for the U.S. National Radio Astronomy Observatory
(Astronomical Image Processing System = AIPS), and in fact the files are quite
similar to the UVFITS format of AIPS. For spectral line data, AIPS cannot
Fourier transform more than eight spectral line channels at a time.
Therefore, following the style of the NRAO VLA, we have archived the 32
channel data that were typically obtained in 4 separate FITS files with 8
channels in each file. A fifth file usually accompanies this data and contains
the broadband continuum data recorded at the same time as the spectral line
data.
2.2.4 Radar data
Radar observations of Halley's Comet were carried out only at the Arecibo
Observatory during November 1985. We have recorded the average echo obtained
during this experiment in a single FITS file. The radar observation is made
by transmitting a single frequency tone in one circular polarization toward
the comet and observing the echo in both polarizations. The echo is observed
in spectral line mode, and a detection is sought at the correct Doppler
shifted frequency given by the ephemeris of the comet. Thus, since this data
type is identical in most respects to a spectral line observation, the data
are recorded in a similar format. For a specular reflection, the echo is
expected to be polarized in the sense opposite to that of the transmitted
signal. However, real surfaces often contain significant power in the same
sense as that trans- mitted, perhaps due to multiple reflections on the
target. We have treated the echo polarization in the same manner as the
orthogonal polarizations in the OH experiments, but with a special key to
designate the "same" and the "opposite" senses of polarization.
2.2.5 Occultations
Many occultation-type experiments were carried out during the Halley
campaign. Unfortunately, relatively few were reported to the International
Halley Watch for inclusion in this archive. The occultation data that are
presented here employed the Milky Way itself as a background source and made
observations of a track across the sky with and without the comet present in
the beam. When carried out as a spectral line experiment, these data result
in a two dimensional data type with spectra taken at many positions along a
track on the sky. We have attempted to preserve the raw data here by saving
these two dimensional images in the FITS file. Thus, a typical file contains:
(1) the data with the comet in the beam; (2) one or more maps with the comet
out of the beam, which were obtained on a different day. We have chosen to
present these different maps as a three dimensional "cube" of data, with
NAXIS = 3. The first axis is the frequency dimension of the spectra. The
second axis is the position of the spectrum in RA. Finally, the third axis,
labeled 'MAP-TYPE' defines which map is being presented. MAP-TYPE = 0 is the
data with the comet in the beam, and MAP-TYPE not equal to 0 gives the map of
the galactic background alone on one or more days of observation. Users are
advised to check the individual FITS headers for further information on the
definition of MAP-TYPE for specific dates of observation.
3. THE RADIO SCIENCE NETWORK INDEX TO THE CD-ROMS
The IHW provides various indices to help users of the archive find the
data that they want. For the Radio Science Network, there are two indices
provided by the project which users will find useful: the quick look index and
the printed archive (see Sec. 4 for a description), both of which contain
information on all observations in the archive. The Radio Science Network
provides a third, discipline specific, index which contains much more detailed
information about the radio observations than the others. In selecting the
information to be included in the Radio Science Index, we have attempted to
include all relevant data from the FITS headers, within limitations imposed by
standards set by the Halley Watch. The detailed format of the Radio Science
index is given in Table VI.
Table VI. IHW Radio Science Network Index Format
______________________________________________________________________________
Field Keyword Type Format Notes
______________________________________________________________________________
1 OBJECT C A20
2 FILE-NUM N I6
3 DATE-OBS D A8 IHW Date Format
4 TIME-OBS N F6.3
5 LONG-OBS C A9
6 LAT-OBS C A9
7 SYSTEM C A8
8 OBSERVER C A24
9 COMMENT ADD. OBS. C A60 May exclude some observers
10 SUBMITTR C A24
11 SPEC-EVT L L1
12 DAT-FORM C A8
13 DIS-CODE C A12
14 DAT-TYPE C A6
15 OBSVTORY C A10
16 TELESCOP C A10
17 LOCATION C A30
18 INSTRUME C A20
19 CENTFREQ N F11.4 in MHz
20 BANDWIDT N F11.4 in MHz
21 BEAMSIZE N F6.4
22 BEAMELON N F6.3
23 BEAMROTA N F6.1
24 BEAMEFF N F6.3
25 EQUINOX N F8.3
26 RAOFF N F7.4
27 DECOFF N F7.4
28 MOLECULE C A10
29 TRANSITN C A20
30 RESTFREQ N F11.4 in MHz
31 RES-SPEC N F11.4 in kHz
32 HISTORY LIMIT N F11.4 in Jy/Beam
33 HISTORY LINEPEAK N F11.4 in Jy/Beam
34 HISTORY ERR-PEAK N F11.4 in Jy/Beam
35 HISTORY LINE-VEL N F11.4 in m/s
36 HISTORY ERR--VEL N F11.4 in m/s
37 HISTORY LINE-WID N F11.4 in m/s
38 HISTORY ERR--WID N F11.4 in m/s
39 HISTORY LINEAREA N F11.4 in Jy/Beam * m/s
40 HISTORY ERR-AREA N F11.4 in Jy/Beam * m/s
41 HISTORY LINEMEAN N F11.4 in m/s
42 HISTORY ERR-MEAN N F11.4 in m/s
43 HISTORY CONTFLUX N F11.4 in Jy/Beam
44 HISTORY ERR-FLUX N F11.4 in Jy/Beam
45 DATE-BEG D A8 Date Format
46 DATE-END D A8 Date Format
47 HISTORY NWINDOW N I2
48 HISTORY WINDOW (1) D A8 Start Date of 1st Window (Date
Fmt)
49 HISTORY WINDOW (1) N F5.3 Start Time of 1st Window
50 HISTORY WINDOW (N) D A8 End Date of Last Window (Date Fmt)
51 HISTORY WINDOW (N) N F5.3 End Time of Last Window
52 HISTORY POINTERR N F10.2 in arcsec
53 HISTORY CALMETH C A20
54 HISTORY CALSRCE (1)C A15 Name of Cal Source 1
55 HISTORY CALSRCE (1)N F10.3 Value of Cal Source 1
56 HISTORY CALSRCE (1)C A15 Units of Cal Source 1
57 HISTORY CALSRCE (2)C A15 Name of Cal Source 2
58 HISTORY CALSRCE (2)N F10.3 Value of Cal Source 2
59 HISTORY CALSRCE (2)C A15 Units of Cal Source 2
60 HISTORY TSYSTEM N F7.1 Value Only
61 HISTORY TRCVR N F7.1 Value Only
62 HISTORY TAUZENTH N F4.2
63 BITPIX N I2
64 NAXIS N I2
65 BSCALE N F15.9
66 BZERO N F10.4
67 BUNIT C A15
68 BLANK N I6
69 DATAMAX N F10.4
70 DATAMIN N F10.4
71 NAXIS1 N I4
72 CDELT1 C A15
73 CRPIX1 C A15
74 CRVAL1 C A15
75 CTYPE1 C A25
76 NAXIS2 N I4
77 CDELT2 C A15
78 CRPIX2 C A15
79 CRVAL2 C A15
80 CTYPE2 C A25
81 NAXIS3 N I4
82 CDELT3 C A15
83 CRPIX3 C A15
84 CRVAL3 C A15
85 CTYPE3 C A25
86 NAXIS4 N I4
87 CDELT4 C A15
88 CRPIX4 C A15
89 CRVAL4 C A15
90 CTYPE4 C A25
91 NAXIS5 N I4
92 CDELT5 C A15
93 CRPIX5 C A15
94 CRVAL5 C A15
95 CTYPE5 C A25
96 NAXIS6 N I4
97 CDELT6 C A15
98 CRPIX6 C A15
99 CRVAL6 C A15
100 CTYPE6 C A25
101 PATH:VOLUME C A8 CD-ROM VOLUME NAME
102 PATH:YEAR SUBDIRECT C A5 YEAR SUBDIRECTORY
103 PATH:MON. SUBDIRECT C A3 MONTH SUBDIRECTORY
104 PATH:DAY SUBDIRECT C A3 DAY SUBDIRECTORY
105 PATH:HOUR SUBDIRECT C A3 HOUR SUBDIRECTORY
106 FILENAME C A8 FILENAME
______________________________________________________________________________
4. THE RADIO SCIENCE NETWORK PRINTED ARCHIVE
In addition to the FITS presentation of the Radio Science Network data,
an additional format is available in the printed archive. This format
provides most of the information that is necessary to make use of the data, as
well as the "data summary" information included in the FITS headers, such as
the line peak intensity and width for spectral line observations. The format
of the printed archive for the Radio Science Network is shown below.
4.1 Printed Format I: OH Subnetwork and Spectral Line Subnetwork
Since the OH Subnetwork and the Spectral Line Subnetwork contain the same
data type, it is most economical to print both subnetworks together in the
same subsection of the Radio Science part of the archive. Detailed
description of this format is in Table VII.
Table VII. Printed Format I
______________________________________________________________________________
Col. FITS Field Field Notes
Keywords Format Header
______________________________________________________________________________
1 DATE-OBS,TIME-OBS DD.TTTTT Date(UT)
10 FILE-NUM I6 RSN#
17 MOLECULE A5 Mol
23 DAT-TYPE (4th character) A1 DT Denotes Subnetwork
25 RESTFREQ (MHz) I6 Freq
32 RES-SPEC (kHz) I4 Res
37 HISTORY TSYSTEM (K) I5 Tsys
43 BEAMEFF (per cent) I2 BE
46 BEAMSIZE (arcsec) I4 HP
51 DIS-CODE (8th character) A1 BS Denotes beam shape
53 Radial Offset of I4 rho
Beam from Nucleus (arcsec)
58 Position Angle of I3 PA
Radial Offset (deg)
For Limits:
62 A "<" symbol A1
63 HISTORY LIMIT (Jy/Beam) F6.1 Line Peak if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
80 A "-" symbol A1 Width
91 A "-" symbol A1 Velocity
For Detections:
63 HISTORY LINEPEAK (Jy/Beam) F6.1 if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
69 A "plus or minus" symbol A1 Line Peak
70 HISTORY ERR-PEAK (Jy/Beam) F5.1 if value>10Jy/Beam
or F5.3 if value<10Jy/Beam
76 HISTORY LINE-WID (km/sec) F4.2
80 A "plus or minus" symbol A1 Width
81 HISTORY ERR--WID (km/sec) F4.
86 HISTORY LINE-VEL (km/sec) F5.2
91 A "plus or minus" symbol A1 Velocity
92 HISTORY ERR--VEL (km/sec) F4.2
For All:
97 SYSTEM A8 System
106 OBSERVER A23 Observer
130 COMMENT NOTE A2 Note
______________________________________________________________________________
4.2 Printed Format II: Continuum Subnetwork
The data in the continuum subnetwork are fundamentally different from the
spectral line data in the previous section. Thus they require anopther
format, listed in Table VIII.
Table VIII. Printed Format II
______________________________________________________________________________
Col. FITS Field Field Notes
Keywords Format Header
______________________________________________________________________________
1 DATE-OBS,TIME-OBS DD.TTTTT Date(UT)
11 FILE-NUM I6 RSN#
18 DAT-TYPE (4th character) A1 DT Denotes Subnetwork
20 CENTFREQ (MHz) I6 Freq
27 BANDWIDT (MHz) I4 Res
34 HISTORY TSYSTEM I5 Tsys
40 BEAMEFF (per cent) I2 BE
43 BEAMSIZE (arcsec) I4 HP
48 DIS-CODE (8th character) A1 BS Denotes Beam Shape
50 Radial Offset of I4 rho
Beam from Nucleus (arcsec)
55 Position Angle of I3 PA
Radial Offset (deg)
For Limits:
60 A "<" Symbol A1
61 HISTORY LIMIT (Jy/Beam) F6.1 Flux Density if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
For Detections:
61 HISTORY CONTFLUX (Jy/Beam) F6.1 if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
67 A "plus or minus" symbol A1 Flux Density
68 HISTORY ERR-FLUX (Jy/Beam) F5.1 if value>10Jy/Beam
or F5.3 if value<10Jy/Beam
For All:
75 SYSTEM A8 System
84 OBSERVER A30 Observer
116 COMMENT NOTE A2 Note
______________________________________________________________________________
4.3 Printed Format III: Occultation Subnetwork
Since the occultation data in this archive is of the same type as the OH
and Spectral Line Subnetworks, they are presented in the same format.
Detailed description is in Table IX.
Table IX. Printed Format III
______________________________________________________________________________
Col. FITS Field Field Notes
Keywords Format Header
______________________________________________________________________________
1 DATE-OBS,TIME-OBS DD.TTTTT Date(UT)
10 FILE-NUM I6 RSN#
17 MOLECULE A5 Mol
23 DAT-TYPE (4th Character) A1 DT Denotes Subnetwork
25 RESTFREQ (MHz) I6 Freq
32 RES-SPEC (MHz) I4 Res
37 HISTORY TSYSTEM (K) I5 Tsys
43 BEAMEFF (per cent) I2 BE
46 BEAMSIZE (arcsec) I4 HP
51 DIS-CODE (8th Character) A1 BS Denotes Beam Shape
53 Radial Offset of I4 rho
Beam from Nucleus (arcsec)
58 Position Angle of I3 PA
Radial Offset (deg)
For Limits:
62 A "<" symbol A1
63 HISTORY LIMIT (Jy/Beam) F6.1 Line Peak if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
80 A "-" symbol A1 Width
91 A "-" symbol A1 Velocity
For Detections:
63 HISTORY LINEPEAK (Jy/Beam) F6.1 if value>10Jy/Beam
or F6.3 if value<10Jy/Beam
69 A "plus or minus" symbol A1 Line Peak
70 HISTORY ERR-PEAK (Jy/Beam) F5.1 if value>10Jy/Beam
or F5.3 if value<10Jy/Beam
76 HISTORY LINE-WID (km/sec) F4.2
80 A "plus or minus" symbol A1 Width
81 HISTORY ERR--WID (km/sec) F4.2
86 HISTORY LINE-VEL (km/sec) F5.2
91 A "plus or minus" symbol A1 Velocity
92 HISTORY ERR--VEL (km/sec) F4.2
For All:
97 SYSTEM A8 System
106 OBSERVER A23 Observer
130 COMMENT NOTE A2 Note
______________________________________________________________________________
4.4 Printed Format IV: Radar Subnetwork
There is only one radar observation in the archive, but for consistency
we have made a printed format for it. The format follows the Continuum
Subnetwork format and is described in Table X.
Table X. Printed Format IV
______________________________________________________________________________
Col. FITS Field Field Notes
Keywords Format Header
______________________________________________________________________________
1 DATE-OBS,TIME-OBS DD.TTTTT Date(UT)
10 FILE-NUM I6 RSN#
18 DAT-TYPE (4th character) A1 DT Denotes Subnetwork
20 CENTFREQ (MHz) I6 Freq
27 BANDWIDT (MHz) I4 Res
34 HISTORY TSYSTEM I5 Tsys
40 BEAMEFF (per cent) I2 BE
43 BEAMSIZE (arcsec) I4 HP
48 DIS-CODE (8th character) A1 BS Denotes Beam Shape
50 Radial Offset of I4 rho
Beam from Nucleus (arcsec)
55 Position Angle of I3 PA
Radial Offset (deg)
61 HISTORY XSECTION F6.1
67 A "plus or minus" symbol A1 Cross Sect. In units of km**2
68 HISTORY ERR-XSEC F5.1
75 SYSTEM A8 System
84 OBSERVER A30 Observer
116 COMMENT NOTE A2 Note
______________________________________________________________________________
5. UNITS IN THE RADIO SCIENCE ARCHIVE
We have attempted to use a fixed set of standard units for the values
given in the IHW archive. These units are given in Table XI. Where these
units are not used, as in the printed archive, the index tables, or in certain
values in the HISTORY section of the FITS headers, attention is explicitly
called to the change of units.
Table XI. IHW Radio Science Units
_______________________________________
Angle Degrees
Length Meters
Time Seconds
Frequency Hertz
Velocity Meters/Second
Flux Density Jansky/Beam*
Radar Cross Section Square kilometers
_______________________________________
* 1 Jansky = 1.0 x 10(-26) Watts per
square meter per Hertz
The adoption of the flux density unit, Jansky per beam, deserves some
additional comment. This unit is well defined: the signal is described in
terms of the flux density of a point source which would produce the same
signal observed from the comet. The explicit use of "per beam" in the unit
acknowledges that the coma is possibly resolved by the beam to an unknown
extent. Some observatories, such as the VLA, have naturally already adopted
this choice of units since they use celestial point sources to calibrate the
instrument. All continuum observations also use Janskys to express their
results regardless of how the data are actually internally calibrated. Thus,
in both of these cases, the Jansky is the obvious choice of unit. For
spectral line work on large single antennas, however, results are typically
expressed in "antenna temperature" since they are calibrated by comparing the
observed signal to a calibration signal of known noise temperature. In recent
years, this unit has become rather confusing as a result of efforts to convert
a relatively well defined observed quantity into a more physically meaningful
unit which gives an approximation to the true brightness temperature of the
source. Thus, various forms of "corrected" antenna temperature are in use at
different observatories, and it is often not clear which corrections have been
made to the data. We therefore favor a system in which the calibration is
achieved by direct comparison of the cometary signal to celestial sources of
known flux density, and the natural unit for such a comparison is the unit of
flux density, the Jansky. Thus, all observations in the archive have been
converted to these units using data provided by the observers.
6. CALIBRATION
Although we have converted the data in the archive to a common unit of
flux density, we have made no attempt to recalibrate data to a common flux
density scale. The calibration scale for radio astronomy is well established
at centimeter wavelengths, and in general, well known standard sources were
used by the network observers. For wavelengths shorter than about 1
centimeter, however, the calibration becomes less precise as atmospheric
attenuation becomes significant in the observations. In most cases,
comparisons to celestial sources are more indirect and observers rely on
absolute calibration schemes as their primary method. Ultimately, though,
even these techniques use known sources, such as the planets, to calibrate the
system, and we have attempted to archive information about these calibration
sources with each observation.
Calibration information that is supplied to us by the observer is given
in the HISTORY section of the FITS header. The HISTORY CALMETH keyword
provides an ASCII string with a brief description of the calibration method
used. Three methods are commonly used: (1) STANDARDS indicates that the data
were calibrated through direct comparison to standard sources; (2) NOISE TUBE
indicates that the data were primarily calibrated by injecting power from a
noise source into the receiver; (3) CHOPPER WHEEL indicates that the "chopper
wheel" method was used; (4) ABSOLUTE calibration is used for the radar
observations presented in this archive and is based on measurements of antenna
and transmitter properties rather than on astronomical standards. This latter
method uses the comparison of the noise power from an ambient temperature load
to that produced by the sky emission to make an estimate of the optical depth
of the atmosphere, and it is commonly used at millimeter wavelengths.
Even in the cases of NOISE TUBE and CHOPPER WHEEL calibration, where
celestial sources are not initially used to calibrate the data, the final
calibration is generally made with celestial sources. Whenever a standard
source is used for this purpose, its name and assumed flux density are given
in the HISTORY CALSRCE keywords. More than one of these keywords may exist
in the header if more than one calibration source is used. For planetary
sources, the assumed brightness temperature is given rather than the flux
density since planetary flux densities vary with distance to the object.
Finally, the system temperature (defined to be the total system noise
temperature including receiver noise and atmospheric and ground pickup) and
the receiver temperature (defined to be the noise temperature of the receiver
alone) are given in the HISTORY TSYSTEM and HISTORY TRCVR keywords; the
atmospheric opacity at zenith is given in the HISTORY TAUZENTH keyword where
appropriate.
7. THE OBSERVERS
Many people have made substantial contributions to the success of the
Radio Science Network of the International Halley Watch. First of all, we
wish to thank the observers who have submitted data to the archive, since
if it were not for their interest and assistance, there would be no archive
at all. These observers are listed in Table XII. We also appreciate those
who attempted to observe comet P/Halley even if they did not get useful data.
In many cases, these early attempts paid off in our later studies of comet
Halley.
Table XII. IHW Radio Science Observers
_____________________________________________________________________________
Observer Affiliation
_____________________________________________________________________________
Abraham, Z. Instituto de Pesquisas Espaciais, Brazil
Altenhoff, W. Max Planck Institut fur Radioastronomie, FRG
Andersson, Ch. Onsala Space Observatory, Sweden
Arnal, E. Instituto Argentino de Radioastronomia, Argentina
Bajaja, E. Instituto Argentino de Radioastronomia, Argentina
Batelaan, P. Jet Propulsion Laboratory, USA
Batrla, W. University of Illinois, USA
Baum, S. University of Maryland, USA
Berulis, J. Lebedev Physical Institute, USSR
Biggs, J. University of Sydney, Australia
Bird, M. Universitat Bonn, FRG
Bockelee-Morvan, D. Observatoire de Paris-Meudon, France
Boriakoff, V. Cornell University, USA
Botti, C. Instituto de Pesquisas Espaciais, Brazil
Bourgeois, G. Observatoire de Paris-Meudon, France
Bretas Filhd, F. Instituto de Pesquisas Espaciais, Brazil
Butner, H. University of Texas, USA
Bystrova, N. Special Astrophysical Observatory, USSR
Campbell, D. National Astronomy and Ionosphere Center, Puerto Rico
Cancoro, A. Instituto de Pesquisas Espaciais, Brazil
Cersosimo, J. Instituto Argentino de Radioastronomia, Argentina
Claussen, M. University of Massachusetts, USA
Cohen, J. University of Manchester, UK
Colom, P. Observatoire de Paris-Meudon, France
Colomb, F. Instituto Argentino de Radioastronomia, Argentina
Comoretto, G. Osservatorio Astrofisico Arcetri, Italy
Cordes, J. Cornell University, USA
Crovisier, J. Observatoire de Paris-Meudon, France
de Pater, I. University of California, Berkeley, USA
Del Ciampo, L. Instituto de Pesquisas Espaciais, Brazil
Despois, D. Universite de Bordeaux, France
Destombes, J. Universite de Lille, France
Duncan, R. CSIRO Division of Radiophysics, Australia
Ekelund, A. Onsala Space Observatory, Sweden
Ekelund, L. Onsala Space Observatory, Sweden
Encrenaz, P. Observatoire de Paris-Meudon, France
Falchi, A. Osservatorio Astrofisico Arcetri, Italy
Forster, R. CSIRO Division of Radiophysics, Australia
Forveille, T. Universite de Grenoble, France
Frerking, M. Jet Propulsion Laboratory, USA
Friehe, K. Instituto de Pesquisas Espaciais, Brazil
Gagliardi, L. Osservatorio Astrofisico Arcetri, Italy
Galt, J. Dominion Radio Astrophysical Observatory, Canada
Gaylard, M. Hartebeesthoek Radio Astronomy Observatory, South Africa
Gerard, E. Observatoire de Paris-Meudon, France
Gossachinskij, I. Special Astrophysical Observatory, USSR
Gulkis, S. Jet Propulsion Laboratory, USA
Harmon, J. National Astronomy and Ionosphere Center, Puerto Rico
Haschick, A. Haystack Observatory, USA
Hasegawa, T. Nobeyama Radio Observatory, Japan
Hoban, S. University of Maryland, USA
Huchtmeier, W. Max Planck Institut fur Radioastronomie, FRG
Irvine, W. University of Massachusetts, USA
Judaeva, N. Special Astrophysical Observatory, USSR
Kaifu, N. Nobeyama Radio Observatory, Japan
Kaufmann, P. Instituto de Pesquisas Espaciais, Brazil
Kinzel, W. University of Massachusetts, USA
Kitamura, Y. Nobeyama Radio Observatory, Japan
Klein, M. Jet Propulsion Laboratory, USA
Krevsa, E. Max Planck Institut fur Radioastronomie, FRG
Kuiper, T. Jet Propulsion Laboratory, USA
Lewis, M. National Astronomy and Ionosphere Center, Puerto Rico
Losovski, B. Lebedev Physical Institute, USSR
Madden, S. University of Massachusetts, USA
Malzoni, M. Instituto de Pesquisas Espaciais, Brazil
Martin, C. Instituto Argentino de Radioastronomia, Argentina
Matthews, H. Hertzberg Institute of Astrophysics, Canada
Mazzaro, R. Instituto Argentino de Radioastronomia, Argentina
Melad, I. Instituto de Pesquisas Espaciais, Brazil
Mirabel, I. University of Puerto Rico, Puerto Rico
Montiero do Vale, J. Instituto de Pesquisas Espaciais, Brazil
Morras, R. Instituto Argentino de Radioastronomia, Argentina
Nelson, G. CSIRO Division of Radiophysics, Australia
Norris, R. CSIRO Division of Radiophysics, Australia
Ohishi, M. Nobeyama Radio Observatory, Japan
Olalde, J. Instituto Argentino de Radioastronomia, Argentina
Palagi, F. Osservatorio Astrofisico Arcetri, Italy
Palmer, P. University of Chicago, USA
Persson, G. Onsala Space Observatory, Sweden
Petroni, M. Instituto de Pesquisas Espaciais, Brazil
Pickett, H. Jet Propulsion Laboratory, USA
Poppel, W. Instituto Argentino de Radioastronomia, Argentina
Reynolds, J. University of Sydney, Australia
Scalise, E. Instituto de Pesquisas Espaciais, Brazil
Schaefer, M. Jet Propulsion Laboratory, USA
Schloerb, P. University of Massachusetts, USA
Schmidt, J. Max Planck Institut fur Radioastronomie, FRG
Schraml, J. Max Planck Institut fur Radioastronomie, FRG
Sestokas, B. Instituto de Pesquisas Espaciais, Brazil
Shang, Q. Yunnan Observatory, People's Republic of China
Shapiro, I. Harvard-Smithsonian Center for Astrophysics, USA
Silva, A. Instituto Argentino de Radioastronomia, Argentina
Snyder, L. University of Illinois, USA
Sorochenko, R. Lebedev Physical Institute, USSR
Stumpff, P. Max Planck Institut fur Radioastronomie, FRG
Suzuki, H. Nobeyama Radio Observatory, Japan
Swade, D. University of Massachusetts, USA
Tateyama, C. Instituto de Pesquisas Espaciais, Brazil
Terasranta, H. Helsinki University of Technology, Finland
Terzian, Y. Cornell University, USA
Thum, C. Institut de Radioastronomie Millimetrique, Spain
Tofani, G. Osservatorio Astrofisico Arcetri, Italy
Tolmachev, A. Lebedev Physical Institute, USSR
Turner, B. National Radio Astronomy Observatory, USA
Urpo, S. Helsinki University of Technology, Finland
Vilas Boas, J. Instituto de Pesquisas Espaciais, Brazil
von Kap-Herr, A. Max Planck Institut fur Radioastronomie, FRG
Walmsley, M. Max Planck Institut fur Radioastronomie, FRG
Wang, J. Yunnan Observatory, People's Republic of China
Wannier, P. Jet Propulsion Laboratory, USA
Webber, J. Haystack Observatory, USA
Winnberg, A. Onsala Space Observatory, Sweden
Wootten, A. National Radio Astronomy Observatory, USA
Zimmermann, P. Universitat zu Koln, FRG
Zinchenko, I. Lebedev Physical Institute, USSR
_____________________________________________________________________________
8. ACKNOWLEDGEMENTS
F. P. Schloerb and W. M. Irvine, as leaders of the radio astronomy
effort, have been aided in their effort by a number of students, post-docs and
secretaries at the University of Massachusetts during the course of our
involvement with the IHW. We gratefully acknowledge the efforts of R.
Bassett, M. Claussen, C. Clemens, R. Molloy, G. Moriarty-Schieven, D. Swade,
and L. Tacconi-Garman, who have provided assistance to the project at various
times throughout its duration.
As leaders of the Radio Science effort, Schloerb and Irvine would also
like to acknowledge especially two of the other members of the Discipline
Specialist Team listed in Table I. W. M. Kinzel, the manager of the Radio
Science Archive, has made a substantial and noteworthy contribution of time
and effort to the actual archiving of the data while serving as a graduate
student at the University of Massachusetts. The archive that exists today
would have been impossible to complete without his participation in the
project. Finally, we would like to thank particularly our Co-Discipline
Specialist E. Gerard for his continued leadership in the field of cometary
radio astronomy, his enthusiastic support of the International Halley Watch,
and his efforts on our behalf.
F. Peter Schloerb and William M. Irvine
Discipline Specialists for Radio Science
Five College Radio Astronomy Observatory
Department of Physics and Astronomy
University of Massachusetts
Amherst, MA 01003