FK4 AND FK4 SUPPLEMENT DESCRIPTION (File 1 of 8) This document describes the eight files that make up the revised version of the FK4 machine-readable catalog. There are seven data files in addition to this descriptive file. The files contain FK4 data for 1950, 1955, 1960, 1965, 1970, 1975, and the FK4 Supplement. The 1950 and 1975 files contain the complete FK4 catalog (1535 stars), ordered by FK4 catalog number; four other files contain data for the 52 polar stars only, in the same order that those stars appear on pages 112-123 of the printed catalog. 1. FK4 Main Catalog All FK4 data files have 134-byte records and share the same format. The Supplement file is different in structure and contains 55-byte records. Below are the first 6 records of FK4 1950 (columns 1-69, then 70-134), column scale above each part: 000000000000000000000000000000000000000000000000000000000000000000000 000000000111111111122222222223333333333444444444455555555556666666666 123456789012345678901234567890123456789012345678901234567890123456789 0001 215 A0p 000547841+0310224+0000945+001038+0000508220011004 0002 242 F5 000629735+0320384+0002790+006787+0010615530027010 0003 394 K0 000652775+0304407-0001404+001236-0001311810053026 0004 508 F0 000742744+0312012+0001695+000063+0000121920021011 0005 556 K0 000902232+0304604-0000662+000087 0000018010032018 00000000000000000000000000000011111111111111111111111111111111111 77777777778888888888999999999900000000001111111111222222222233333 01234567890123456789012345678901234567890123456789012345678901234 +28485212+198779-000100-01583 0000222018005001270016BD+28 4 +58522677+198579-000111-01766-0050625024008001470017BD+58 3 -46012371+198565-000109-01771 0001390054024001580021CD-46 18 +45473894+200361-000119+00049 0001852028012001690023BD+45 17 -28044140+200474-000130+00204 0001592044025001970028CD-28 26 The additional descriptive data to the right of the table below is included to illustrate the format of the data in the catalog data files for any given quantity. It is the data contained in the first record of file 2 (1950 data). Data Files (Files 2,3,4,5,6 and 7 of 8) Bytes Format Description 1- 4 I4 FK4 star number. File is ordered by this number. 1 5- 8 F4.2 Magnitude; if a range is given in the book, this 2.15=215 contains the brighter magnitude (to 0.1). 9 A1 If 'V', the star is variable. 10- 13 A4 If a range of magnitudes is given in the book, this contains '-' in 10 and the fainter mag. in 11-12 (F2.1). Similarly, if both components of a double star are catalogued, byte 10 contains '+' and the magnitude of the secondary is in 11-13 (F3.2). Normally 10-13 are blank. 14- 16 A3 HD spectral type. A0p 17- 20 A4 If both components of a double star are catalogued, byte 17 contains '+' and 18-20 contain the HD spectral type for the secondary. If the entry is for a single star whose spectrum varies, byte 17 contains '-' and 18-20 contain the second spectral type. Normally 17-20 are blank. 21- 29 I2,I2, Right ascension (epoch and equinox of the file), F5.3 00h05m47s.841 = 000547841 30- 37 F8.3 d(RA)/dT, time seconds per tropical century. +310s.224/cy = +0310224 38- 45 F8.3 1/2 d2(RA)/dT2, time seconds per (trop cy)**2. 38- 45 +0s.945/(cy)**2 = +0000945 46- 52 F7.3 Proper motion in RA, time seconds per trop cy. 46- 52 +1s.038/cy = +001038 53- 58 F6.3 d(p m in RA)/dT, time sec per (trop cy)**2. 53- 58 +0s.005/(cy)**2 = +00005 59- 62 F4.2 Mean epoch in RA, in years. The first two digits of the year are omitted. 1908.22 = 0822 63- 66 F4.4 Std dev in RA at mean epoch, time seconds. 63- 66 0s.0011 = 0011 67- 69 F3.3 Std dev in pm in RA, time sec per trop cy. 67- 69 0s.004/cy = 004 70- 78 A1,I2, Declination (epoch and equinox of file), I2,F4.2 +28 48'52".12 = +28485212 79- 85 F7.2 d(Dec)/dT, arc seconds per tropical century. 79- 85 +1987".79/cy = +198779 86- 92 F7.2 1/2 d2(Dec)/dT2, arc seconds per (trop cy)**2. 86- 92 -1".00/(cy)**2 = -000100 93- 98 F6.2 Proper motion in Dec, arc seconds per trop cy. 93- 98 -15".83/cy = -01583 99-102 F4.2 d(p m in Dec)/dT, arc sec per (trop cy)**2. 99-102 0".00/(cy)**2 = 000 103-106 F4.2 Mean epoch in Dec, in years. The first two digits of the year are omitted. 1902.22 = 0222 107-109 F3.3 Std dev in Dec at mean epoch, arc seconds. 107-109 0".018 = 018 110-112 F3.2 Std dev in pm in Dec, arc sec per trop cy. 110-112 0".05/cy = 005 113-117 I5 Catalog number of star in the Boss GC. 113-117 127 = 00127 118-121 I4 Catalog number of star in the N30 catalog. 118-121 16 = 0016 122-131 A2,A8 Durchmusterung number of the star, in the form DMSZZNNNNN, DM='BD', 'CD', or 'CP', S='+' or '-' BD+28 4 132-134 F3.3 Parallax of star, arc seconds. Usually this field is blank. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 2. FK4 Supplement (File 8 of 8) 0000000001111111111222222222233333333334444444444555555 1234567890123456789012345678901234567890123456789012345 0293200100036 52 K2 000156545-000030-10471585-00034012 0293200200044 62 G0 000216199+006324+34224868+00985034 0293200300048 66 G5 000226561+000641+27234796+00051 0293200400075 57 K0 000307744+000276+13070505-00024 Again the descriptive data to the right of the table illustrates the format of the data fields. This data is the first record of the supplement file (file 8) Cols. Format Description First Star 1- 4 4X Record identifier, always 0293 for this file. 0293 5- 8 I4 FK4Sup star number. File is ordered on this number. 2001 9-13 I5 Catalog number of star in the Boss GC. 00036 14-16 F3.1 Magnitude. 5.2 = 52 17-20 A4 HD spectral type. Byte 17 is the prefix (blank except for #3505, which is 'c'); 18 is the class; 19 is the subclass; and 20 is the suffix (usually blank, but may be 'p' or 'e'). Two stars have type ' Oe5'. 21 A1 Double star indicator. If '2', the star is double. However, unlike the main FK4, there is no information about the secondary. 22-30 I2,I2, Right ascension (epoch and equinox 1950.0), F5.3 HHMMSS.SSS. 00h01m56s.545 = 000156545 31-37 F7.3 Proper motion in RA, time seconds per trop cy. -0s.030/cy = -000030 38-46 A1,I2, Declination (epoch and equinox 1950.0), I2,F4.2 sDDMMSS.SS. -10 47'15".85 = -10471585 47-52 F6.2 Proper motion in Dec, arc seconds per trop cy. -0".34/cy = -00034 53-55 F3.3 Parallax, arc seconds. This field is present for only a few of the records, and is not present in the printed catalog. 0".012 = 012 The file contains 1987 records for 1987 stars. -------------------------------------------------------- -------------------------------------------------------- 3. History The original machine-readable catalog consisted of seven files broken down by left and right pages for 1950 and 1975, left and right pages for the circumpolar stars, and a file for the supplement. The catalog was supplied to W. M. Owen, Jr. of the Jet Propulsion Laboratory (JPL) in January of 1989. Modifications to the data and format were made at JPL to correct miscellaneous errors, convert old BCD coding to ASCII representation, add Durchmusterung numbers and trigonometric parallaxes, and combine the left and right pages to single files containing one logical record per object in a uniform format. The revised catalog was then returned to the ADC at NASA GSFC, where the descriptive file (also prepared mostly at JPL) was modified. (The logical record length of the Supplement file was changed from 80 bytes to 55 bytes per record at the ADC because bytes 56-80 were blank.) The revised catalog was then archived permanently. Wayne H. Warren Jr. Astronomical Data Center 1989 March Modified by: Susan E. Gessner 1990 December