HD (S0): HENRY DRAPER star catalog, edition 1985 (19930406)
FILES:
Name Magnitude range Dec (2000) range #Stars Dataset
hd70.s0 -1.6 <= mag <= 7.0 -90 <= Dec <= +90 15631 S-11
hd7180.s0 7.1 <= mag <= 8.0 -90 <= Dec <= +90 31521 S-11
hd8185.s0 8.1 <= mag <= 8.5 -90 <= Dec <= +90 32522 S-11
hd8690.s0 8.6 <= mag <= 9.0 -90 <= Dec <= +90 50287 S-11
hd91n.s0 9.1 <= mag <=12.1 0 <= Dec <= +90 19721 S-12
hd91s1.s0 9.1 <= mag <=12.1 -30 <= Dec < 0 36358 S-12
hd91s2.s0 9.1 <= mag <=12.1 -90 <= Dec < -30 46083 S-12
hd_nomag.s0 NO MAGNITUDES -90 <= Dec <= +90 40033 S-12
CONTENTS: Henry Draper Catalog, edition 1985
DATASET: The above files are contained in the datasets S-11 and S-12, as indicated above (the version of each is 19930406). Dataset S-11 contains a total of 129961 stars. Dataset S-12 contains a total of 142195 stars. Availability on HyperSky CD-ROM: Vol. 1 (1993)
DESCRIPTION: These datafiles contain the HENRY DRAPER CATALOG. Begun in the early 1900s, the intent of the catalog was to provide spectral classifications of all stars down to the faintest possible magnitude limits of the object-prism plates available at the time. This goal was achieved with complete coverage down to about magnitude m(pg)=9 in the original catalog published by Cannon and Pickering (1918-1924). The catalog was subsequently extended to fainter stars in selected areas of the sky. These extensions were published by Cannon in 1936, and by Cannon and Mayall in 1949. The "HD" prefix is used here for stars in both the catalog and its extensions. A single prefix is possible because the HD star numbering system is extended uniformly from the original HD through the extensions. Consequently any HD number is unique, regardless of its membership in the original catalog or the extensions. Elsewhere the prefix "HDE" is sometimes applied to stars from the extension catalogs.
The HyperSky files are based on the machine-readable version of the HD catalog provided on the NASA/GSFC Astronomical Data Center (ADC) cd-rom "Selected Astronomical Catalogs", Volume 1. The ADC version, dated 1985, contains the concatenation of the original HD catalog and the first volume of its extensions, corrected for all errors known as of Feb 1985. The last extension volume (HD stars 272151-359083) is not included because no machine readable version of this extension existed as of 1985. The HyperSky files contain a grand total of 272156 HD stars.
SELECTION EFFECTS FOR STARS FAINTER THAN 9TH MAGNITUDE
As mentioned above, the HD catalog offers essentially complete coverage down to about magnitude 9. Below 9th, the HD extensions were directed at selected areas, and do NOT cover the sky uniformly. These areas are most dramatically illustrated in the HyperSky datafile containing the HD stars without magnitudes: hd_nomags.s0. Although this file contains a sparse scattering of stars throughout the sky, it contains HUGE concentrations of stars from in certain specific rectangular (roughly square) regions. You can see these regions easily by starting HyperSky with ONLY hd_nomags.s0, or perhaps loading just one other bright star file, flamstd.s0 for instance. Below are some notable regions saturated with stars from file hd_nomag.s0:
Center Region Square Height Features
RA= 5.5h, Dec=-69.5 Dorado 10 deg Large Magellanic Cloud
RA= 6.1h, Dec=+18.5 Ori,Tau,Gem,Aur 32 deg winter Milky Way
RA=19.1h, Dec=+15.0 northern Aql 10 deg summer Milky Way
RA=20.0h, Dec=+37.5 central Cyg 10 deg summer Milky Way
Such selection effects are less pronounced but still present in the HD HyperSky files for stars fainter than 9th that have magnitudes: hd91n.s0, hd91s1.s0 and hd91s2.s0. These files give a generally broader coverage of the entire sky, but high concentrations of stars are still evident in many areas. A few (of many) examples can be found in southern Gemini, around the Pleiades, and in several areas around the north pole. In each of these areas there are distinctly rectangular regions roughly 5 degrees square that contain large numbers of HD stars fainter than 9th magnitude.
DATA: The HyperSky datafiles contain the following data from the HD catalog:
POSITION: Right Ascension and Declination are based on the 1900 catalog values, precessed to equinox 2000. The 1900 HD positions are accurate to 0.1m of RA and 1 arc second of Declination. Thus the precessed RA and Declinaton are also limited to this accuracy.
MAG: Both photovisual and photographic magnitudes are provided in the HD catalog. The HyperSky files use photovisual magnitudes. In rare cases when a photovisual magnitude is not available, but the photographic magnitude is available and used, the comment "pg" will appear on a line below the star identification.
TY: The HD catalog provides for a three-letter spectral type. In the vast majority of cases this type will be only two letters (eg, "A0"), which are displayed under the TY heading. If a third HD spectral type letter exists, the complete type will be displayed on a line below the star identification, (eg, "A0p").
IDENTIFICATION: The HD number of the star.
COMMENTS: The comment lines contain the following information, provided if available for each HD star or object:
* Durchmusterung catalog identification:
Prefixes indicate the specific Durchmusterung as follows:
BD = Bonner Durchmusterung
CD = Cordoba Durchmusterung
CP = Cape Photographic Durchmusterung
* Object identification notes: The ADC version of the HD catalog uses special magnitude values to identify special objects. Consequently no true magnitude is available for these objects, so all such objects will appear in HyperSky HD file hd_nomag.s0. For objects in this file, one of the following single-word comments may appear: "nebula", "variable", "nova", "cluster".
For example, by using file hd_nomag.s0 in conjunction with the Burnham Celestial Handbook cross-reference (HyperSky dataset M-1), you can identify the Tarantula nebula in the Large Magellanic Cloud as HD 38268 = CP-69 456. This object is marked as a "nebula" in the HD catalog.
* Alternate magnitude type: If the HD magnitude provided by HyperSky is photographic instead of photovisual, the short comment "pg" will appear.