Explanation of the columns in the double star list.

The data in this list are a compendium of the United States Naval Observatory's main catalog, neglected stars, notes, and alternate star name list. The data in your list are taken from these documents and filtered according to your submitted specifications.

Row color explanation:

• A pair shown in green means that the data for the pair are probably accurate.
• A pair shown in yellow means that the WDS has listed the pair as neglected or of uncertain identification.
• A pair shown in red means that the pair has not been observed since 1970, its last observation date is unknown, or that the WDS lists it as "dubious".

The USNO gives a detailed explanation of the neglected stars. Click here to go there.

The J2000 coordinates are formatted such that they can be copied into tools such as Aladin or WikiSky to display the DSS image at that location.

The WDS Id is a 10 digit string that reflects the low precision J2000 coordinate of the pair.

The Dsc Id gives the discoverer's initials or designator, and the number of the pair in their published list.

Const is the IAU 3 letter abbreviation of the constellation in which the pair is located.

Estimated magnitudes of the components

The estimated magnitudes of components in the WDS listing come from the discover's original estimates, which date back as far as the early 19th century. These are often in error by a significant amount when compared to modern photometry. While some efforts have been made by the WDS maintainers to correct these estimates, many remain as originally published.

This list tries to correct these spurious estimates by searching the Gaia DR 2 catalog for stars that correspond to the WDS stars, as described below.

A mv is the visual magnitude of the primary. Other bandpasses for a pair are described in the notes column.

A G mv is the visual magnitude (mvG) of the primary as derived from the Gaia DR 2 data if available. The algorithm used for this derivation was developed by Wilfried Knapp and is based on the other bandpasses observed by Gaia:

mvG = 3.9379083526304 +
      (0.269235360436179 * (g ^ 1.36701081887491) -
      (0.123879978164097 * (g - red)) -
      (0.943379695375539 * (g - b));

Here red, g, and b are the red, g, and blue bands observed by Gaia.

See the Gaia bandpass docs for more detail. Note that the Gaia data does not, in general, include and naked eye stars, and this tool excludes stars fainter than 18.0mv.

B mv is the visual magnitude of the secondary.

B G mv is the visual magnitude of the secondary, as derived from the Gaia DR2 data. To the caveats listed for the A star above, add that many of the B stars are so close to their primary as to not be seen by Gaia. At times in a crowded star field (e.g. a cluster) a Gaia secondary will be found that is not correlated with the WDS secondary.

Other columns

Spectra is the spectral type of the primary. At times the secondary's spectrum is listed as well. If the orbit of the stars are know, this field is shown in white

First and last θ are the the earliest and most recent position angles of the pair, in degrees. If the orbit of the stars are know, this field is shown in white

First and last ρ are the earliest and most recent separations, in arc seconds, of the pair.

First and last Obs are the first year the pair was observed and the year of the most recent observation.

Orbit: Pairs with known orbits or optical (linear):

• If there is a know orbit for the star, both the most recent observation and the value calculated for the present (true of date) position are shown in white.
• The most recent is the top number, true of date is the bottom figure. For orbits, the quality of the orbit is given by the number in parenthesis in the comments column. They vary from 1, definitive, to 5, indeterminate.
• Cyan numbers under the quality number indicate that the orbit has been diagrammed. Clicking these numbers will bring up the diagram in a new tab on your browser.

Pairs with linear plots:

• If there is a linear plot for the star, clicking the number under the "Linear" tag will bring up the plot in a new tab on your browser.

AKA (Also Known As) lists other common names for the pair.

Comments:

• Blue mags indicates that the pair's magnitude is photographic, Johnson, or other Blue band.
• Red mags indicates that the pair's magnitude is from the Johnson or other Red band.
• Dubious indicates that the pair is listed is probably an error in the original discoverer's listing.
• IR mags indicates that the pair's magnitude is its infrared magnitude. Usually 4-6 mags brighter than the visual magnitude.
• Linear indicates that linear elements for this pair have been determined, indicating that the pair is probably not physical.
• Low precision coordinates indicate that the precise position of the pair is not known.
• Neglected indicates that the pair is listed as neglected by the WDS.
• Optical indicates that the pair is probably not physical.
• Uncertain indicates that the identification of the pair is uncertain.
• Uncertain Position indicates that the pair's position is uncertain.

Notes: If a star has an entry in the WDS notes document, the word "Note##" where ## is the number of the note appears in this column. Clicking on it will take you to the text of that note.