Fourth Catalog of Interferometric Measurements of Binary Stars
William I. Hartkopf & Brian D. Mason
U.S. Naval Observatory, Washington, DC
Harold A. McAlister
Center for High Angular Resolution Astronomy
Georgia State University, Atlanta, GA 30303
Note: As of January 2018,
the Fourth Interferometric Catalog will no longer be maintained. This change,
after 35+ years, is due to staffing limitations at USNO (primarily the
retirement of WIH). Over the coming months, the observations of single stars /
never-resolved pairs will be copied to a new WDS "single-star supplement", whose
format will be similar to that of the WDSS. All measures of resolved pairs will
be copied to the main WDS catalog as needed. Preliminary versions of the "WDSSSS"
will be posted; your comments and suggestions regarding content, format, etc.
will be welcome, as always.
Note: In April 2020 coordinates
were corrected, WDS components were added and other errors, ambiguities and
inconsistencies were removed as part of another project producing a more correct
final version of this catalog. No new data were added.
The following description is adapted from a paper by Hartkopf et al.
(2001, AJ, 122, 3480.)
The Fourth Catalog of Interferometric Measurements of Binary Stars
includes all published measures of binary and multiple star systems obtained by
high-resolution techniques (speckle interferometry, photoelectric occultation
timings, etc.), as well as negative examinations for duplicity. A brief summary
and statistical analysis of the contents of the catalog follow.
The Fourth Catalog of Interferometric Measurements of Binary Stars began
in 1982 as an internal database at the Georgia State University Center for High
Angular Resolution Astronomy (CHARA), tabulating binary star observations made
using the technique of speckle interferometry by that group's speckle camera.
The Speckle Catalog soon grew to encompass other published speckle
efforts, then all published astrometric and photometric data for binary stars
(and single stars observed in duplicity surveys) obtained by other high angular
resolution techniques (lunar occultations, adaptive optics, eyepiece
interferometry, Hipparcos, etc.) as well. This extended the catalog's baseline
of observations back by nearly a century, to the efforts of Schwarzschild &
Villiger (1896). Results of surveys based on various infrared speckle or
imaging techniques were later added, as well, even though some of these don't
really qualify as high resolution.
Two printed editions of the catalog were published in the 1980's (McAlister &
Hartkopf 1984, 1988), and web versions have been available since the early
1990's (Hartkopf et al. 2001a, 2001b). After the speckle efforts at CHARA
were suspended in the late 1990's (in order to devote more resources to their
long-baseline interferometry project) one of the authors (WIH) transferred the
catalog (still nicknamed the Speckle Catalog in honor of its origins) to
the U.S. Naval Observatory, whose own speckle efforts had begun earlier in the
Although the catalog is updated regularly, statistics are updated on only an
occasional basis. The table below summarizes the contents of the catalog as of
9 January 2018. In addition to the astrometric totals presented here, the
catalog includes 73,894 observations of photometric data only.
Figures 1 - 3 illustrate the distribution of
catalog data with time, separation, and declination, respectively.
Fourth Interferometric Catalogue Statistics (as of 09 January 2018)
Number of resolved stars: 66,225
Number of never-resolved stars: 27,330
Total number of stars: 93,555
Median separation 0".89
Breakdown of data by method:
resolved unresolved total
Tycho 40,871 1,001 41,872
Hipparcos 13,880 16,798 30,678
USNO Speckle 22,294 4,758 27,052
CHARA Speckle 18,527 6,479 25,006
Other speckle, AO, etc 31,686 14,466 46,152
Eyepiece interferometry 3,085 700 3,785
Occultation 1,825 770 2,595
Multi-aperture interferometers 3,276 1,053 4,329
Hubble 2,040 3,638 5,678
Other techniques 25,582 43,126 68,708
TOTAL 163,066 92,789 255,855
Of the resolved total, 2,473 are vector separations (from either
occultations or one-dimensional IR speckle).
The catalog is divided into 24 one-hour right ascension
bands, as follows:
00 hrs ...
01 hrs ...
02 hrs ...
03 hrs ...
04 hrs ...
05 hrs ...
06 hrs ...
08 hrs ...
09 hrs ...
10 hrs ...
11 hrs ...
12 hrs ...
13 hrs ...
14 hrs ...
16 hrs ...
17 hrs ...
18 hrs ...
19 hrs ...
20 hrs ...
21 hrs ...
22 hrs ...
The entire catalog is also available in plain text
and gzipped plain text versions. Sizes are
roughly 44 and 8MB, respectively.
Entries for each system are comprised of two parts: an identification line
containing designations from various catalogs, followed by individual measures
sorted in order of observation date (see the format
file). Major changes with this version include coordinates to 0.01s in RA and
0".1 in DEC, improvements in the formatting of filter information to allow
longer wavelengths, and the addition of technique codes. The ID line format was
changed slightly in July 2007 to allow additional space for long names (e.g.,
Each observation includes a reference code linked to a
reference file. Similarly, systems having notes are flagged with links to a
notes file. An additional change in July 2007
provided links to the Sixth Orbit Catalog for pairs with published visual or
A common notes file is used for all USNO double star catalogs (WDS, plus
the Interferometric and Orbit catalogs). As a result, the notes file will
include systems in addition to those in this catalog. Also, because the
notes file is much larger, it has been divided into 24 smaller files for
faster linking to the individual catalog measurements files.
Your comments regarding either style or substance are welcome. Please
report any errors you run across in the catalog to usnowds-AT-gmail.com .
- Anderson, J.A. 1920, ApJ 51, 263
- Hartkopf, W.I., Mason, B.D., McAlister, H.A., Turner, N.H.,
Barry, D.J., Franz, O.G., & Prieto, C.M. 1996 AJ, 111, 936
- Hartkopf, W.I., McAlister, H.A. & Mason, B.D. 2001a,
Third Catalog of Interferometric Measurements of Binary Stars, CHARA
Contrib. No. 4, http://www.ad.usno.navy.mil/wds/int3.html
- Hartkopf, W.I., Mason, B.D., Wycoff, G.L., & McAlister, H.A. 2001b,
Fourth Catalog of Interferometric Measurements of Binary Stars,
- Horch, E.P., Franz, O.G., & Ninkov, Z. 2000, AJ 120, 2638
- McAlister, H.A. & Hartkopf, W.I. 1984, Catalog of
Interferometric Measurements of Binary Stars, CHARA Contrib. No. 1
- McAlister, H.A. & Hartkopf, W.I. 1988, Second Catalog
of Interferometric Measurements of Binary Stars, CHARA Contrib. No. 2
- Merrill, P.W. 1922, ApJ 56, 40
- Schwarzschild, K. & Villiger, W. 1896, Astr. Nach. 139, 353
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