COLUMN Format DATA
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1 - 10 A10 2000 Coordinates
11 - 17 A7 Discoverer & Number
18 - 22 A5 Components
24 - 27 I4 Date (first)
29 - 32 I4 Date (last)
34 - 37 I4 Number of Observations (up to 9999)
39 - 41 I3 Position Angle (first - XXX)
43 - 45 I3 Position Angle (last - XXX)
47 - 51 F5.1 Separation (first)
53 - 57 F5.1 Separation (last)
59 - 63 F5.2 Magnitude of First Component
65 - 69 F5.2 Magnitude of Second Component
71 - 79 A9 Spectral Type (Primary/Secondary)
81 - 84 I4 Primary Proper Motion (RA)
85 - 88 I4 Primary Proper Motion (Dec)
90 - 93 I4 Secondary Proper Motion (RA)
94 - 97 I4 Secondary Proper Motion (Dec)
99 - 106 A8 Durchmusterung Number
108 - 111 A4 Notes
113 - 130 A18 2000 arcsecond coordinates
Description of Data in the WDS
Columns 1- 10: The hours, minutes, and tenths of minutes of Right
Ascension for 2000, followed by the degrees and minutes of
Declination for 2000, with + and - indicating north and
south declinations. The positions given represent our best
estimates of these values. Where possible, these are based
on the ACRS and PPM data, with proper motion incorporated.
Columns 11- 17: The discoverer, identified by his one-to-three letter code,
and his discoverer's number, if assigned. The reference list
should be consulted first to identify individuals. However,
some discoverer designations do not appear in this list, for
various reasons, and a supplementary list is provided.
Columns 18- 22: Components, when the object has more than two. The Lick IDS
scheme has been discontinued, and components are now
referred to by the traditionally employed lower-case
letters. The rather awkward upper-case designations, e.g.
ABXC, have been changed to the form AB-C, etc. We have noted
some confusion on the part of observers and students alike,
as to how to designate components in multiple systems.
Traditionally, these have been designated in order of
separation, thus AB, AC,...., or in the cases where close
pairs are observed blended, AB-C, AB-D,.... In some
instances, differing resolution limits produce situations
where observations are intermixed, thus AC, AB-C, and so
forth (in all too many cases, carelessness on the part of
the observer does not permit us to determine with certainty
how the observation is to be interpreted). There are also
many instances where later observations have revealed a
closer companion; these are designated Aa, Bb, etc. In a few
cases wider, later discoveries have also been so denoted.
Columns 24- 27: The dates of the first and last observations of an object
29- 32: (of satisfactory accuracy), up to the present date.
Columns 34- 37: The number of measures of the object.
Columns 39- 41: Position angles in degrees for the dates listed in columns
43- 45: 26-34. Crude positions (e.g., NP) of the past have been
changed to their degree equivalent with an accompanying note
in the data line of the measurement database. Position
angles are unprecessed in this catalog (i.e., they are for
the mean date of observation).
Columns 47- 51: The distances in seconds of arc, and tenths, for the dates
53- 57: listed in columns 26-34. Some separations are treated by the
codes found in columns 100-101, or in the Notes.
Columns 59- 63: Magnitudes of the two components. See the Introduction for
65- 69: discussion.
Columns 71- 79: Spectral type of A, or of two components, if space permits.
See the Introduction for discussion.
Columns 81- 84: The components of the proper motion in seconds of arc per
85- 88: 1000 years, in right ascension reduced to great circle, and
in declination. Specifically, this catalog lists 15mu(alpha)
cos(delta), where mu(alpha) is in seconds of time, and
mu(delta) is in seconds of arc. Both quantities are reduced
to a time unit of 1000 years. The exceptions are those
objects coded P for which an explanation is given under the
description for Columns 108 to 111. + and - indicate
eastward and westward motions in Right Ascension, and + and
- those north and south in Declination. Where possible, this
comes from Tycho-2.
Columns 90- 93: Proper motion of the secondary, when known.
Columns 99-106: Durchmusterung number of the object in the system used by
the Henry Draper Catalogue: Bonn from +89 degrees to -22
degrees inclusive, Cordoba from -23 degrees to -51 degrees
inclusive, Cape Photographic from -52 degrees to -89
degrees inclusive. When a star is not contained in the
Durchmusterung proper to its declination zone, but is
contained in another Durchmusterung, this is so indicated
in the Notes. Other components having different
Durchmusterung numbers are also indicated in the Notes.
Columns 108-111: The following codes are contained in these columns:
N: Notes found in the Notes table.
B: Summary line gives blue (Johnson U or B, blue
photographic, etc.) magnitudes
C: Orbit and Linear solution. A published orbit exists
and this system has a Linear Solution as well. A "C"
code, then, indicates both an "O" and an "L" code.
D: Has measure in Delta-M catalog
I: Identification uncertain. Match of object at precise
position with WDS pair may or may not be correct.
Currently under examination.
K: Summary line gives K-band or other infrared (>1
L: Linear solution. Linear elements for this pair have
been determined. Linear Elements Catalog is
currently under devlopement.
M: Magnitude modified. Magnitudes have been corrected
to the Tycho-V scale based on other systems measured
by the discoverer and Tycho.
N: Notes found in WDSNOT MEMO of WDS
O: Orbit, briefly described in WDSNOT MEMO and has
entry in Orbit Catalog
P: 100-year proper motion in right ascension and
R: Summary line gives red (Johnson R or I, red
photographic, etc.) magnitudes
S: Statistically different parallax and proper motion
indicates that this pair is non-physical.
T: Statistically the same parallax within the errors and
similar proper motion or other technique indicates
that this pair is physical.
U: Proper motion or other technique indicates that this
pair is non-physical.
V: Proper motion or other technique indicates that this
pair is physical.
X: A "Dubious Double" (or "Bogus Binary"). This pair may
represent a positional typo in the original publication
(so we're looking in the wrong location), an optical
double disappearing due to radically different proper
motions, a plate flaw, or simply a pair not at a
magnitude, separation, etc., sufficiently similar to
those noted when the first measure was added (making
it too faint, too close, etc.). We would certainly like
to know about any circumstances where you have found or
Y: Statistically different parallax for the components
indicates they are non-physical.
Z: Statistically the same parallax within the errors would
indicate the components are physical.
have ascertained the mystery behind these pairs.
At present, column 108 is reserved for N, column 109 for
O, L, C, or X and column 110 for D. The other codes can
occur in any column.
Columns 113-130: The hours, minutes, seconds and tenths of seconds (when
known) of Right Ascension for 2000, followed by the degrees,
minutes, and seconds of Declination for 2000, with + and -
indicating north and south declinations. The positions given
represent our best estimates of these values. Where
possible, these are based on the Hipparcos and Tycho data,
with proper motion incorporated. While the arcminute
coordinate (columns 1-10) refer to the primary of a multiple
system, the arcsecond coordinate (columns 113-130) refer to
the primary of the subsystem. For example, while the BC pair
of an A-BC multiple will have the same 10 digit WDS
coordinate, the arcsecond coordinate of the BC pair will be
at the "B" position.