Double Star Program

The Washington Double Star Catalog (WDS) maintained by the United States Naval Observatory is the world's principal database of astrometric double and multiple star information. The WDS Catalog contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 149104 systems based on 1899327 means as of Tue Jun 11 06:14:05 EDT 2024 .


The availability of large astrometric catalogs and the admirable acumen of users has led to the republishing of the same measures and identification of the same measures and identification of the same "new" systems by multiple data-miners. This has significantly increased the amount of work needed to properly incorporate these data into the USNO double star catalogs. Therefore, in the future, data mining results will be added to the WDS and WDSS at the discretion of the catalogers. Furthermore, preference will be given to data prepared by those specifically associated with the original catalog project.

As can be seen in the figure below, the WDS and the other catalogs we maintain are being added at a prodigious rate. A great deal of this work is coming from data mining, especially DR2 from Gaia. While this can be useful, it is always there to be mined, and based on some private discussions it is possible that the best and final Gaia astrometric solution will not be produced until DR4 or later.

WDS Growth

Further actual observations cannot be replicated. The observations you make tonight cannot be made tomorrow night or next week. Given the slow-motion of many of the pairs we look at, to first order, this claim is absurd. However, it does get to the crux of the issue: your observations are a unique dataset that cannot be replicated.

As a result, we have generated a list of pairs that need to be observed. This can be regenerated each time there is a major addition to the WDS, These lists include pairs which either are unconfirmed or pairs which have not been measured in many years ("many" set arbitrarily at 20 years). In the initial formulation two lists would be generated:

The above lists are in WDS summary line format.

For these neglected pairs, even a non-detection can be useful if your observing capability is much greater than the parameters of the pair in question. For the neglected pairs where date - last is a very large number, the pair may be lost or miscataloged, and it may involve detective work or the perusal of old articles. This type of investigative work may be found especially appealing.

If the WDS and associated databases were helpful for your research work, the following acknowledgment would be appreciated:

"This research has made use of the Washington Double Star Catalog maintained at the U.S. Naval Observatory.''

A notification of references to relevant papers is appreciated.