Introduction to CPC2 release 2 ============================== The second release of the CPC2 data (Second Cape Photographic Catalogue) contains the following files: readme.cpc = this file cpc2_2.m = the main catalog, 266629 stars cpc2_2.a = appendix, 8040 stars paper.ps = journal paper describing this release cpc2_chk.f = simple Fortran source code to check data This introduction describes the following: 1) What is the CPC2_2 ? 2) Example lines 3) The catalog format 4) Catalog statistics In case of problems or questions, please contact Dr. Norbert Zacharias / AD U.S. Naval Observatory 3450 Mass.Ave. N.W. Washington DC 20392 e-mail: nz@usno.navy.mil ============================================================== 1) What is the CPC2_2 ? ----------------------- The CPC2 is an astrometric, photographic catalog covering the Southern Hemisphere (-90 <= DC <= +2 degree) to a limiting magnitude of about 10.5 in a visual-red bandpass of 530-640 nm. The same x,y and photometry data has been used as with the first release of the CPC2 (de Vegt et al. 1993, A&A Supl 97, 985; Zacharias et al. 1992, A&A 254, 397). This release 2 is based on a complete new plate-by-plate reduction using the Hipparcos Catalogue (ESA, 1997, SP-1200). Details can be found in the corresponding paper (Zacharias et al. 1999, AJ). This release 2 does not contain proper motions. The positions given are on the Hipparcos system (equinox J2000) and for the mean epoch of observation, which is between 1961.7 and 1973.2. This catalog is mainly intended to be combined with other astrometric catalogs to derive proper motions. It also serves as a cross-check for individual stars, giving a high precision position at its epoch. The main catalog (cpc2_2.m) contains the 266629 "good" stars with a formal error in the position of 200 mas or less (average is 53 mas) and with at least 2 plates (4 images) used for the position. The appendix catalog (cpc2_2.a) contains all single image stars and those with a formal error in the position of 201 to 499 mas (8040 stars in total). The remaining 1462 stars of the release 1 are no longer given in this release due to unsolved problems. 2) Example lines ---------------- For easier reading of the format description (see below) the first and last 5 lines of the main and appendix catalog are duplicated here: cpc2_2.m: CPC2 mag RA SPD sx sy nu epRA epDC ------------------------------------------------------- 10023 87 484827421 607449 17 36 10 70808 70827 10026 104 18267827 681919 19 62 7 70900 70885 10024 81 537107841 782928 17 28 10 70809 70832 10028 66 787998323 822048 28 16 9 71065 71030 10016 105 325910460 1168541 113 5 2 70655 70614 ------------------------------------------------------- 923114 100 1191141695 331876677 104 19 2 70570 70570 920175 88 89442269 331886622 31 64 2 70280 69853 923109 96 1190825143 331911102 55 35 2 70570 70570 923093 95 1187528251 331983541 81 79 2 69656 69532 920105 94 56476147 332021643 104 78 2 68921 68921 ------------------------------------------------------- cpc2_2.a: ------------------------------------------------------- 10029 103 801505240 719825 85 98 1 71380 71380 10022 104 454295589 916656 86 116 1 71881 71881 10042 104 1184217132 1354135 81 88 1 71861 71861 10030 103 760299628 1945235 89 106 1 71114 71114 10017 106 409127262 2280215 88 105 1 71881 71881 ------------------------------------------------------- 923285 102 1240121637 331992477 96 145 1 70832 70832 923295 95 1244635516 332004384 36 241 2 70118 70157 920254 96 121294579 332023671 104 131 1 68945 68945 923264 103 1231590010 332035761 191 237 1 70758 70758 923266 91 1232596644 332091570 225 250 1 70758 70758 ------------------------------------------------------- 3) The catalog format --------------------- All data given is in positive integers. All columns are filled, and at least one blank is between each column, thus an easy unformatted READ statement can be used. column unit description ----------------------------------------------------- CPC2 original CPC2 star number mag 1/10 CPC2 photographic magnitude RA mas right ascension at epoch epRA SPD mas south pole distance at epoch epDC = declination + 90 degree sx mas formal standard error in RAcosDC sy mas formal standard error in DC nu number of used plates epRA 1/1000 yr mean epoch of RA (-1900) epDC 1/1000 yr mean epoch of DC (-1900) 4) Catalog statistics --------------------- The result from running the cpc2_chk.f program is: input file name: cpc2_2.m number of lines: 266629 minimal and maximal values for each column: 10001 5 518 607449 0 1 2 61698 61698 923307 126 1295974454 332021643 200 200 12 73215 73483 input file name: cpc2_2.a number of lines: 8040 minimal and maximal values for each column: 10007 9 147398 719825 1 1 1 61696 61696 923300 124 1295778454 332091570 499 499 6 72291 72111