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SAGUARO ASTRONOMY CLUB DOUBLE STAR DATABASE VERSION 2.1 dated Tuesday 25 March 1991 This compilation of data was begun in an effort to provide a comprehensive observing list for use at the telescope. This data is released for private use of anyone who wishes to use this database. Please do not sell this database in any form. The members of the Saguaro Astronomy Club (pronounced sa-war-oh) of Phoenix, Arizona have provided much of the effort to compile this database. However, it could not have been completed without the skill of a variety of people who are not SAC members. Thank you to all. Many members of our astronomy club have always enjoyed pretty multiple stars and in an effort to provide a large list of these objects, this project was begun. We are not foolish enough to believe that it is complete, but it should be a good starting point for even the most avid amateur double star observer. We were lucky enough to receive a copy of the Washington Double Star (WDS) catalog from Paul Brown in Canada. We wrote some programs to glean the best and brightest from that massive list and wound up with the data which you have in this database. The program was written to get all stars with magnitudes in the WDS that included a primary brighter than 9 and a secondary brighter than 13. If the stars were closer than 2 arc seconds then the magnitudes had to match within one magnitude. The authors of the SAC double star database think this has given us a list which will be useful to owners of modest telescopes. The database is distributed in ASCII text files which have been compressed using PKZip to save space. See the READ-ME.TXT file for more details on the contents of the distribution diskettes. We divided the database by RA hour, into five separate files. Each of the DBL21? data files has the same layout. Fields are separated by commas. Character fields are delimited with a double quotes. A description of the fields and what data they contain follows: Database Format Summary:
Details about each field follows: Field Number: 1 Name: NAME Size: 8 (Char) Name of the discoverer of this multiple system. The problems in this field are generally going to be with either the Herschel or Struve family of discoverers. William Herschel released his binary star findings is several catagories labeled with Roman numerals based on how difficult the star is too divide. This information was not available to us in the WDS, so you will find several stars labeled H 40 in the catalog, one would be H II 40, another H IV 40. This is an obvious reason that professional double star astronomers refer to these stars by their ADS or IDS numbers.
If the object was not listed in a preceding catalog, we used the Star designation. Field Number: 2 Name: STAR Size: 11 (Char) Designations by which this pair may be known. The same abbreviations as the CON field are used in this field. Generally, this will be the Bayer or Flamsteed designations. However, there are some variable star designations and proper names in this field. Field Number: 3 Name: RA Size: 7 (Char) Epoch 2000 position in hours and minutes of Right Ascension. Field Number: 4 Name: DEC Size: 6 (Char) Epoch 2000 position in Declination degrees and minutes. Field Number: 5 Name: CON Size: 3 (Char) Constellation in which the object is found in IAU format, given in the table below. Only upper case abbreviations are used for ease of programming using case-sensitive commands.
Field Number: 6 Name: COMP Size: 4 (Char) If this is a multiple system, which components of the triple (or more) are in this record. For instance, if this field has ABXD then this field of data applies to the star system D in relation to the brightest pair in this multiple star AB. Field Number: 7 Name: MAG1 Size: 4 (Char) Magnitude of the primary star. Field Number: 8 Name: MAG2 Size: 4 (Char) Magnitude of the secondary star. Field Number: 9 Name: SEP Size: 5 (Numeric) Separation of the pair in arc seconds. Field Number: 10 Name: PA Size: 3 (Char) Position Angle of the pair in arc degrees clockwise from North. Field Number: 11 Name: TIRION Size: 8 (Char) The charts in the Tirion Sky Atlas 2000.0 that map the area of sky in which the star is located. This is included so that a less detailed view of the area will be available to star hoppers. Field Number: 12 Name: U2000 Size: 15 (Char) The charts in the Uranometria 2000.0 that map the area of sky in which the star is located. It is not guaranteed that all multiple stars plotted on U2000 are contained in the database but we are trying. Field Number: 13 Name: SPEC Size: 3 (Char) Spectrum of the primary, or the binary pair if a spectroscopic binary. Field Number: 14 Name: YEAR Size: 4 (Char) Year the measures of this pair were taken. Field Number: 15 Name: ADS Size: 5 (Char) Number from the Aitken Double Star catalog, a common cross-reference. Field Number: 16 Name: NOTES Size: 54 (Char) Several abbreviations were used in the Notes section: cpm = common proper motion, the pair is moving through The Galaxy in the same direction and at the same speed. They are probably gravitationally bound together. eclp-bin = eclipsing binary, a system that is edge-on to Earth and the stars pass in front of each other, changing the total magnitude. orbit calc'd = an orbit (maybe a preliminarily one) has been calculated for this system. Several references in a large astronomical library will provide a drawing of the orbit. The more famous pairs are in Burnham's Celestial Handbook. spect-comp = spectrum composite, the two spectra of the binary form a single spectrum that is the addition of the stars in the multiple star system. sp-bin = spectroscopic binary, a pair whose spectra change as the motion of the system moves through different angles to the Earth. Many very close binaries are spectroscopic and cannot be separated visually at the eyepiece. var = variable, the magnitude of the star changes with time. HINTS ON USING THE SAC DOUBLE STAR DATABASE The layout of the data was thought out to try and let the user get the type of listing that is preferred with as few problems as possible. Users who have taken the time to write or call have said that a wide variety of database managers will make it easier for the sophisticated double star observer to utilize the data in a variety of forms. People have used dBase III, Paradox, PC File, PC File dB, Microsoft Works, Wampum and a few have used a word processor to search and sort the SAC database. It is even possible Import it into Lotus 123 as a Text file. Several people have considered burning it into a ROM for use in a telescope control program. Of course, if you do not need overly complex search routines, the provided SACDBL.EXE program from Dan Ward will suffice. It allows the user to make a fine observing list quickly. See the REPORTS.DOC file for more details. CONTRIBUTORS Dan Ward did error corrections, fine tuned the data field formats, wrote the install file, edited the documentation and developed the SACDBL report generator program included with this disk set. A.J. Crayon did error corrections and assisted indirectly in developing the install and observing list program because Dan recycled some code that he and A.J. had jointly developed in the past. Brian Skiff provided us with error checking data and gave us much input on what to include for each entry. Steve Stanford wrote the program which determined the Tirion and U2000 chart numbers. Steve Coe co-wrote the file you are reading and checked and entered data. Alan Gore parsed out the star names from the Notes as given in the WDS and checked and entered data. John and Tom McGrath checked and entered data. Kent Hepburn ran the precession and chart number programs. He also checked and entered data. Roger Wegehoft of Ashton-Tate provided some dBASE code to strip excess blanks out of the middle of some data fields, which allowed us to reduce the overall size of the database by over 500k! Wayne Gary provided valuable suggestions for fine tuning some of the fields formats. REVISION HISTORY Version 1.0 was the raw data from the output of a Quick Basic search routine that was written by Bill Anderson and Steve Coe and run against the Washington Double Star catalog as we received it. Version 1.1 was the output from Alan Gore's dBase III+ program to parse the star names from the NOTES. Version 1.2 contained the precessed values for position and added the chart numbers. Steve Stanford wrote the chart numbering program and Kent Hepburn interfaced it with the data from the WDS. Version 1.3 was a quick check to make certain that we had not lost any "famous" doubles while dealing with the above operations. Version 1.4 was the output of a comprehensive check that lasted several months trying to catch any errors, large or small, in the data or documentation. All the above versions were internal to the SAC and did not get a general release to the public. Versions 1.5 thru 1.8 were intermediate revisions done by Dan Ward to eliminate some data format inconsistencies. A few non-SAC members received copies of one or more of these versions. When Dan finished 1.9, the rest of the team went through it again to make one more check prior to release. Version 2.0 is hereby placed in the public domain. It is our first release of the double star database for general use. Version 2.1 is released to fix a problem that Quick Basic had with values of Declination near the equator. The algorithms in QB just don't understand negative zero!! A dec such as - 00 32 was forced to become positive. So we had to go through all the stars near the equator and check their declinations. FINAL NOTES We realize that such an undertaking could not possibly be completed without some errors or typos creeping into the database. We would like you to get in contact with us if you find any of three types of problems. One, just plain errors, either typos or problems we did not know about. Two, places in the database where we have no data in that field and you know what should go there. Three, ideas on how better to arrange the data or programs you have written to manipulate the data. It is hoped that over a period of time we can hunt down mistakes and make the database as error free as possible. Thank you for any help you can render in attaining that goal. Steve Coe 4919 W. Saguaro Dr. Glendale, Az. 85304 PH. (602) 939-3787 A. J. Crayon 13819 N. 37th Ave. Phoenix, Az. 85023 Ph. (602) 938-3277 Dan Ward can be reached on CompuServe at his ID number of 72040,3357. His address is included with the report generator program. |
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