1 I/193 Page 1 - - *********************************************************** * * * * * * * * * PPM South Star Catalogue * * * * * * * * * *********************************************************** - - compiled by 0 U. Bastian (1) and S. Roeser (1) - in collaboration with 0 L.I. Yagudin (2) and V.V. Nesterov (3) - with contributions from 0 D.D. Polozhentsev (2), Kh.I. Potter (2), R. Wielen (1) and Ya.S. Yatskiv (4) - - 0 1) Astronomisches Rechen-Institut, Heidelberg, 2) Pulkovo Observatory, St. Petersburg, 3) Sternberg Institute, Moscow, 4) Kiev Observatory, Kiev. - - 0 Heidelberg, October 1992 1 Page 2 - - *********************************************************** * * * * * Introduction to PPM South * * * * * *********************************************************** - - 0 Preface ======= 0 The idea of this introduction to PPM South is to deliver a short explanation together with the catalogue itself. It briefly describes the way in which PPM South was constructed and the contents of the catalogue on magnetic tape. It should not be understood as a detailed description of the work performed in the construction of the catalogue. This will be given in a forthcoming paper (Roeser et al., 1993). - - 0 Contents ======== - 1. Scope of PPM South 3 2. Construction of the catalogue 4 3. Properties of PPM South 8 4. Practical usage of PPM South 12 5. List of Critical Comments on Individual Stars 13 6. List of Remarks on Individual Stars 18 7. Explanation of the machine-readable version 20 0 References 23 Acknowledgements 25 1 Page 3 - 1. Scope of PPM South ===================== 0 PPM South gives positions and proper motions of 197179 stars south of about -2.5 degrees declination. Its main purpose is to provide a convenient, dense and accurate net of astrometric reference stars on the southern celestial hemisphere. This net is designed to represent as closely as possible the new IAU (1976) coordinate system on the sky, as defined by the FK5 star catalogue (Fricke et al., 1988). In other words, it is a representation of this system at higher star densities and fainter magnitudes. 0 Until recently the SAO Catalogue served the same purpose. There are three major reasons to replace SAOC now: 0 1) SAOC is a representation of the now obsolete FK4 system of positions and proper motions. Astronomers should have a direct access to the FK5 system. 0 2) The accuracy of positions and proper motions in SAOC is no longer satisfactory. Astronomers should have a more accurate tool. Over more than a century astrometrists have accumulated a vast treasure of measured star positions. The fact that much of this treasure is now available in machine-readable form and the power of present-day computers make it easy to analyse and combine this amount of data. 0 3) Proper motions in SAOC were derived from only two separate source positions per star. This lack of redundancy lead to a large number of coarse errors in that catalogue. With more than two measurements per star such errors can be largely avoided. In this way astronomers now get a more reliable astrometric tool. 0 PPM South is the southern-hemisphere complement to the PPM Star Catalogue (Roeser and Bastian, 1991), which covers the northern hemisphere, plus a strip between the equator and about -2.5 degrees declination. At the border line a continuous transition between the northern and southern part was tailored in such a way that no overlap, nor gaps, nor double entries occurred. 0 The star density of PPM South is slightly higher than that of its northern counterpart. The accuracy of the present-epoch positions is roughly twice that in the north. In fact, all of PPM South is as precise as the "High-Precision Subset" of PPM (north). So, for the first time in the history of astronomy, the practical coordinate system is denser and more precise on the southern than on the northern hemisphere. 0 Compared to SAOC the mean star density is higher by a factor of 1.5, but between the equator and -20 degrees declination it is higher by a factor of 2. The accuracy of present-epoch positions 1 Page 4 - and proper motions is higher by a factor of 6 to 10, depending on declination. 0 The high present-epoch accuracy of PPM South is due to the inclusion of the recently completed FOKAT-S and CPC-2 catalogues. FOKAT-S (Yagudin et al., 1993) is a fourfold coverage of the southern sky, photographed around 1984 in a Soviet-Bolivian cooperation. CPC-2 (Zacharias et al, 1992) also is a fourfold coverage of the southern sky, photographed around 1966 at the Cape of Good Hope. 0 The data files following this Introduction to PPM South are analogous and complementary to the resp. files of PPM (north). Combining the corresponding files will provide the user with a catalogue of 378910 reference stars on the whole sky. - - 2. Construction of the catalogue. ================================= 0 The construction of the catalogue proceeded in much the same way as described in the Introduction to PPM (north). Only few, yet important changes to that procedure were made, and will be mentioned below. - Step 1: Compilation of the star list. 0 The star list for PPM South was constructed starting from the preliminary version of FOKAT-S (Bystrov et al., 1989) which contains 203135 stars. All stars of FK5 (Basic FK5 plus Bright Extension), SRS and SAOC south of -2.5 degrees declination were added, if not already included. In the course of the work a few thousand stars had to be deleted (because either they are non-existent or already in PPM North, or else have no satisfactory observational history). On the other hand, a number of close companions to FOKAT-S stars and a small list of stars of special interest were added. This gave the final list of 197179 stars. - Step 2: Identification of stars in the source catalogues 0 The complete list of source catalogues is given in Chapter 3, below, along with an explanation of their abbreviations, with bibliographic references and some statistics. 0 The stars in each of the source catalogues were identified with 1 Page 5 - the objects of the star list. This was done in a fully automatic process. Problem cases recognized in this process were investigated manually to detect typing errors in the source catalogues, to correctly identify double star components, to avoid the effect of grossly incorrect positions in the star list etc. 0 Prior to the identification of Astrographic Catalogue data (given as original x,y plate coordinates) a plate reduction had to be performed, see step 4, below. - Step 3: Construction of a preliminary system of positions and proper motions. 0 A preliminary system of positions and proper motions is necessary to eliminate systematic deviations between the individual source catalogues. For this purpose we used the SRS catalogue (Smith et al., 1989) with the preliminary proper motions given there. Nominally it is a representation of the FK4 system. For observational epochs before 1920 this turned out to be too sparse and too inaccurate. Therefore the GC (Boss, 1936) was added, after removal of the systematic deviations between SRS and GC, both in positions and proper motions. - Step 4: Reduction of source catalogues to the preliminary system 0 Zonal systematic deviations as well as magnitude- and colour-de- pendent systematic deviations between each of the source catalogues and the preliminary system were determined and eliminated. The zonal corrections were done by a two-dimensional moving-average filter technique, as sketched by Roeser (1990). 0 For the reduction of the Astrographic Catalogue plates an intermediate compilation catalogue of 144 787 stars was constructed from all source catalogues except AC. Two versions of it were published as "Preliminary PPM South" (Bastian et al., 1990) and "Preliminary PPM South, Version 4/91" (on the CD-ROM of NASA's Astronomical Data Center, 1991). But even with this catalogue it was not possible to fully exploit the high inherent quality of the raw AC data in a normal single-plate astrometric reduction. 0 A three-stage procedure was applied, therefore: - 1) A first-order single-plate reduction is performed. The resulting celestial coordinates are used to cross-identify the stars on overlapping plates. - 2) A first-order plate-overlap solution follows as second stage. Each plate is connected to all immediately overlapping plates. This gives a more rigid and more precise plate-to-sky transformation. The accuracy of the resulting celestial 1 Page 6 - coordinates is no longer dominated by the reference catalogue, but by the inherent accuracy of the plate measurements. - 3) The residual differences, both to the reference catalogue and to the overlapping plates, are investigated thoroughly. Systematic defects of the measured plate coordinates (such as magnitude equations, higher-order distortions, coma, or colour equations) can be detected and corrected in this way. If necessary, stages 2 and 3 were repeated. - Step 5: Determination of weights for the source positions 0 In any least-squares adjustment, weights have to be assigned to individual measurements, according to their mean errors. Magnitude-dependent mean errors of the positions were determined for each source catalogue. Different approaches were used, according to need. The following paragraph gives but a few examples. 0 For early-epoch catalogues the mean errors were preferentially taken from Eichhorn (1974). However, investigation of the Yale zone catalogues yielded that some of them, especially the latest ones, were in fact much better than estimated by Eichhorn. For the Carlsberg Meridian Circle catalogues (CMC 1985-1991) the differences to FK4 were investigated by R. Bien (1988). Extrapolation to fainter magnitudes was possible using information given within the CMC catalogues. For Astrographic Catalogue zones the differences between positions of the same star measured on different (overlapping) plates were investigated. For SRS the mean errors given by its authors (Smith et al. 1989) were used, with some modification for the bright stars. 0 All weights were chosen to be conservative estimates, in order to ensure that the accuracy of PPM South will not be overestimated. - Step 6: Least-squares adjustment 0 A standard weighted least-squares adjustment of the mean positions and proper motions was performed for each star - separately for right ascensions and declinations. Automatic tests for unduly large scatter among the measurements (based on the chi-square sum) and automatic elimination of obvious outliers (based on appropriately normalized individual residues) were implemented. All stars having bad chi-square sums beyond a certain significance limit, but still not showing obvious outliers, were marked as "problem cases" (see flag 'P' in byte 127 of the machine-readable catalogue). This occurred in about 1500 cases. 1 Page 7 - Step 7: Manual treatment of difficult cases 0 The automatic outlier elimination deleted about 9000 measured coordinates (out of more than 2.5 million). Tight restrictions however, were imposed on this automatic process in order to avoid spuriously "good" results. This created almost 1000 "difficult cases" that were treated manually. A majority of these turned out to be coarse errors in the source catalogues, mixed-up double star components etc. For about 200 objects no satisfactory solution could be found. These were added to the "problem cases" of step 6, giving a total of 1724 PPM stars with flag 'P'. - Step 8: Transformation from the preliminary to the final system 0 The positions and proper motions derived so far had to be transformed from the preliminary system (described above) to the new IAU (1976) coordinate system, as defined by FK5. 0 Comparison of our preliminary system with final IRS (Corbin 1991), on the system of FK4, showed that there were almost no relevant differences. The sole exception are the proper motions in right ascension south of -70 degrees declination. Incidentally, however, the preliminary SRS system is closer to an undisturbed sphere than the final IRS system for present epochs. This follows from the comparison of preliminary PPM South with provisional HIPPARCOS results (Lindegren, 1992). 0 Therefore we decided to apply no changes at all to the preliminary system. The plots of Lindegren (1992) thus give a good indication of the regional deviations of the PPM system from a perfect coordinate sphere for present epochs. They also show that the PPM system is indeed very close to the FK5 system, both on the southern and on the northern celestial hemisphere. 0 The transition from FK4 system to FK5 system followed exactly the same procedure as was used in the construction of FK5 (Fricke et al., 1988). - Step 9: Introduction of FK5 data for FK5 stars 0 For the stars contained in FK5 Part I (the Basic Fundamental Stars) and in FK5 Part II (the Bright Extension Stars), PPM gives the original FK5 data. These were introduced by simply copying them from the machine-readable version of FK5. - Step 10: Provision of cross-references and auxiliary data 0 In addition to the astrometric data PPM gives cross-references to other star catalogues, magnitudes, spectral types and a number of 1 Page 8 - flags for each star. 0 Cross-references were determined by different methods, ranging from direct cross-identification (based on positions only) to simply copying historic work done by others (in the cases of catalogues having low positional accuracy such as DM and HD). Cross-references are given explicitly for six catalogues: Bonner Durchmusterung and Cordoba Durchmusterung (abbreviated DM), SAO Catalogue, Henry Draper Catalogue (HD) and Cape Photographic Durchmusterung (CPD). Three more cross-references are given implicitly by flags (see chapter 7, explanation of the machine-readable version): 0 Flag 'F' in byte 130 denotes the stars contained in FK5 (Part I plus the Bright Extension). 0 The double star flag 'D' (byte 128) was created by cross-referencing PPM with the Catalogue of Components of Double and Multiple Stars (Dommanget, 1988). 0 The magnitudes given are mostly V magnitudes, copied from CPC-2. They are indicated by flag 'V' in byte 131. V magnitudes from FK5 are given for the FK5 stars (flag 'F'). The magnitudes for the remaining 33 000 stars of PPM South are an inhomogeneous collection from various sources. 0 The majority of spectral types are HD data. Again, FK5 data were copied for FK5 stars. 0 Various sorts of auxiliary information are given in the List of Critical Comments and in the List of Remarks (see Chapters 5 and 6) and indicated by the 'C' and 'R' flags. - - 3. Properties of PPM South =========================== - Random errors + _____________ 0 The table below shows a summary of the error budget of PPM South. Each line of the table gives the following data for different declination zones: The number of stars in the zone, the average number of source positions per star, the average number of stars per square degree, the average of the mean epochs (for right ascension and declination), the average of the mean errors of proper motion (for right ascension and declination) and the 1 Page 9 - average of the mean errors of position at epoch 1990 (again for right ascension and declination). Units are seconds of arc and seconds of arc per century, respectively. At the bottom of the table the corresponding values for SAOC are given for comparison. 0 Note that the accuracy of all PPM South is as high as that of the High-Precision Subset of PPM (north). - Table 1: Error budget of PPM South 0 Zone No. No. Dens. mean ep. mean err. mean err. stars obs. /sq.d. 1900+ prop. mot. pos. 1990 0 -2.5- -20 60657 5.6 10.2 62.3 62.1 0.28 0.28 0.11 0.11 -20 - -40 62048 6.6 10.3 63.8 62.4 0.32 0.31 0.11 0.11 -40 - -60 47121 5.8 10.5 60.5 60.4 0.31 0.32 0.12 0.12 -60 - -90 27353 7.0 10.2 58.6 60.9 0.27 0.30 0.11 0.11 0 total 197179 6.1 10.3 61.8 61.6 0.30 0.30 0.11 0.11 0 SAOC,south 126000 2.0 6.5 30 30 1.5 1.5 1.2 1.2 - Note that (on average) more than 6 measured positions are available per star. This redundancy allowed us to discover (and avoid) a large number of gross errors in the source catalogues. It ensures that PPM South contains very few coarse errors for stars with 4 or more positions (more than 90 percent of all stars). For 1801 PPM South stars the redundancy was not sufficient to resolve discrepancies between the source positions. They are indicated as unreliable by the 'P' or 'C' flags mentioned above. We kept these stars in PPM South, because for the majority of them the PPM data will still be correct to a few tenths of an arcsec. And even the rest will be within a few arcsec at most. - Source catalogues + _________________ 0 More than 1 250 000 source positions (i.e. right ascensions and declinations) entered into the least-squares adjustments for PPM South. The following table lists the various groups of source catalogues used and the total number of positions taken from each group. More information on many of the catalogues as well as bibliographic references are given in the book by Eichhorn (1974). 1 Page 10 - Table 2: Source Catalogues 0 Astrographic Catalogue 482 000 FOKAT-S 203 000 CPC-2 172 000 Yale zone catalogues 128 000 "AGK1" 126 000 CPC 62 000 Sydney SSC 22 000 CMC4, CMC5 20 000 SRS 19 000 Perth Cat. of Astrogr. Ref. St. 9 000 Melbourne Gen. Cat. 3 to 5 8 000 0 Total 1 251 000 0 Here, "AGK1" stands for the different catalogues of the "Catalog der Astronomischen Gesellschaft, Zweite Abtheilung" and its South American extension, the catalogues Cordoba A to D and La Plata A to F. - Numbering. + __________ 0 The assignment of running numbers to the stars is a straightfor- ward continuation of that for PPM (north). It starts with number 181732 for the first star and ends with number 378910. As in PPM (north) the stars are arranged in bands of 10 degrees width in declination. Within each of these bands they are ordered according to right ascension. This arrangement was also used in the SAO Catalogue. 0 As a side remark we mention that in Preliminary PPM South the stars had running numbers starting with 500001. This was to ensure that no confusion with the final PPM number can arise. Furthermore, it ensures that any data taken from the preliminary catalogue can be easily recognized as such. - Systematic Errors + _________________ 0 We did our very best to ensure that PPM is on the system of FK5. Such a goal, however, can be reached to a certain accuracy only. We estimate that the residual systematic deviations between PPM South and the FK5 system have a typical size of 0.05 arcsec for the positions at mean epoch and of 0.2 arcsec per century for the proper motions. 0 These numbers do not hold, however, for a few special groups of objects: The very blue stars (spectral types B2 and earlier), the very faint stars (fainter than about 11.5 in photographic magnitude) and those very bright stars (brighter than about 7) 1 Page 11 - that are not in FK5. Because these groups are very small by number it was neither possible to check our preliminary system to the desired accuracy, nor could we correct the individual source catalogues to this system with the desired accuracy. So we just do not know anything about possible systematic errors for these small groups. - Missing bright stars + ____________________ 0 PPM and PPM South are not intended to be an inventory of the sky, but to provide a practical coordinate system on the sphere. This is why no special efforts were taken to make them complete to some limiting magnitude. Nevertheless, it would clearly be advantageous if all bright stars were included. We plan, therefore, to produce a supplementary star list, containing the few hundred objects brighter than magnitude 8.0 which are missing now. - Some Statistics + _______________ 0 PPM South gives 125 420 SAOC numbers. This corresponds to more than 99 percent of all SAOC stars in the celestial region covered by PPM South. It gives 121 817 HD numbers, corresponding to roughly 75 percent of all HD stars in the region. 190 061 stars carry either a BD or a CoD number, 136 586 stars have a CPD number and 151 018 have a spectral type. 0 There are 12 376 double star flags ('D'), 1724 problem cases ('P' flags), 77 critical comments ('C' flags) and 33 less important remarks ('R' flags). The 'R' flags refer to double star companions and to variable stars mostly. They are not in any way intended to be exhaustive or complete. 0 The number of FK5 stars ('F' flags) in PPM South is 1160. In passing, we note that in PPM (north) inadvertantly no 'F' flags and no FK5 data were given for two stars: FK5 3942 = PPM 161 and FK5 1270 = PPM 178197. 1 Page 12 - 4. Practical usage ================== 0 PPM South gives positions for a standard epoch (J2000) and a standard coordinate system (mean equator and equinox for J2000 in the new IAU (1976) system of astronomical constants. 0 To apply the catalogue as astrometric reference at a different observational epoch, but still in the J2000 coordinate system, proper motions must be taken into account. For most purposes a simple linear formula (position difference equals epoch difference times proper motion) is sufficient. But note that this procedure will give inaccurate results close to the pole. Better formulae are given e.g. by Murray (1983) and in the introduction to FK5. 0 To apply PPM South as astrometric reference for a different equator and equinox, but still in the IAU (1976) system of astronomical constants, precession has to be taken into account. The relevant formulae and numerical values are given e.g. by Lieske (1979) and in the introduction to FK5. 0 Note that simply precessing from J2000 to B1950 will still not give results in the old (FK4) astronomical coordinate system. This differs from the new IAU (1976) system by a correction to the precessional constant, a correction to the position of the vernal equinox, by the treatment of elliptical aberration and by complicated zonal corrections. In general, this adds up to about an arcsec in position and several tenths of an arcsec per century in proper motion. In the region between -60 and -80 degrees declination the difference between the FK4 and the FK5 system is especially large. It amounts to 1.6 arcsec in right ascension at epoch 2000, and to about 1 arcsec/century for the proper motion in right ascension. 0 In File 3 of the machine-readable version we therefore publish positions and proper motions for equinox and epoch B1950 on the system of FK4, as we did for PPM (north). 0 Application of proper motion and precession still gives mean positions. In order to derive apparent positions for PPM objects one has to apply nutation, aberration, stellar parallax, and relativistic light bending, in addition (see e.g. Murray, 1983). For most practical uses of PPM these effects can be ignored. But PPM South contains a small number of stars with fairly large parallaxes. They are not indicated in the catalogue. 0 For each star PPM South gives mean errors for right ascension and declination at their respective mean epochs T. Standard error propagation calculus can be used to calculate the mean error PPM position for an epoch t different from the mean epoch: Denoting the mean error of one coordinate at mean epoch by E(T), the mean 1 Page 13 - error of proper motion by E(PM), the mean error of position at epoch t is given by 0 2 2 2 2 E(t) = E(T) + E(PM) * (T-t) 0 Using more PPM stars in an application will usually give better results because of the partial cancellation of the purely accidental errors of the PPM data. However, this improvement will never get beyond the systematic errors of PPM, as discussed in the previous chapter. - - 5. List of Critical Comments on Individual Stars ================================================ 0 The following list gives, for each star included: The PPM number and a critical comment. 0 All stars included in this list carry the 'C' flag. Their astrometric data should be regarded as unreliable. - 187259 See remark to PPM 187260. 0 187260 Double star. Companion is PPM 187259. Components may be mixed up. 0 198815 Northern component of ADS 9728. Proper motion derived from 3 positions around 1900 and a re- constructed one for the CPC-2 epoch. The position of this star in Yale16 is wrong. CPC-2 contains the southern component in duplicate. 0 206258 Seems to be double. Probably there is another star a few arcsec to the south east. 0 209551 Double star SAO 147542 / SAO 147543. Components possibly mixed up in photographic source catalogues. 0 218925 Double star, photographic source catalogues measured combined image. 0 219535 Western component of a 3 arcsec double. SAO data grossly wrong due to mixing of components. 0 220938 Companion to PPM 220939 1 Page 14 - 0 220939 Companion to PPM 220938. Not properly resolved in the photographic source catalogues. 0 221658 Double star ADS 7423. Bright component is SAO 155267. Fainter companion, about 9 mag, 5 arcsec to the south. Not properly resolved in the photographic source catalogues. 0 222456 Double star. Companion is PPM 222457. Components may be mixed up. 0 232367 Double star. Companion is SAO 160197. Components may be mixed up. 0 236431 Seems to be double, with a separation of 2 to 3 arcsec. 0 240280 Double star SAO 165078 / SAO 165077. Components possibly mixed up in photographic source catalogues. 0 241502 Double star ADS 16688. Separation around 5 arcsec. All photographic source catalogues measured a combined image. 0 252684 Double star. Companion is PPM 252685. Components may be mixed up. 0 252685 Double star. Companion is PPM 252684. Components may be mixed up. 0 252900 Close companion to SAO 174237. SAO 174237 is not in PPM, is about 1 mag brighter than PPM 252900 and situated about 5 arcsec to the north of PPM 252900. 0 254989 Seems to be double. Separation 3 to 4 arcsec. SAO proper motion grossly wrong. Components mixed up in the source catalogues. 0 259116 Double star. Companion is PPM 259117. Components may be mixed up. 0 259117 See remark to PPM 259116. 0 261849 Double star, photographic source catalogues measured combined image. 0 263277 South-eastern component of a 4 arcsec pair having roughly equal magnitudes. 0 263375 Double star. Companion is PPM 263376. Components may be mixed up. 1 Page 15 - 0 263376 Double star. Companion is PPM 263375. Components may be mixed up. 0 265426 Double star. Companion is SAO 159864. Components may be mixed up. 0 266532 May be double. Suspected separation 2 to 3 arcsec in right ascension. 0 266613 Double star. Companion is SAO 185199. Components may be mixed up. 0 268784 Double star. Companion to PPM 268785. SAO 187168. SAO data wrong due to mixing of components. 0 268785 Double star. Companion to PPM 268784. SAO 187168. SAO data wrong due to mixing of components. 0 268984 Double star. Companion is PPM 268985. Components may be mixed up. 0 268985 See remark to PPM 268984. 0 275452 Double star. Companion is SAO 192230. Components may be mixed up. 0 278376 Double star. Companion is SAO 193927. Components may be mixed up. 0 283089 Double star. Companion is SAO 197176. Components may be mixed up. 0 283868 Double star. Companion is PPM 283869. Components may be mixed up. 0 283869 See remark to PPM 283868. 0 286548 This is SAO 200445, the brighter, north-eastern component of a double. The companion is SAO 200444. Separation about 8 arcsec. 0 286920 Double star. Companion is SAO 200759. Components may be mixed up. 0 291906 Double star, photographic source catalogues measured combined image. 0 293743 Double star. Companion is SAO 206544. Components may be mixed up. 1 Page 16 - 294532 Double star. Companion is PPM 294533. Components may be mixed up. 0 294533 See remark to PPM 294532. 0 294735 Double star. Companion is PPM 294737. Components may be mixed up. 0 294872 Double star. Companion is SAO 207516. Components may be mixed up. 0 297036 Double star Co 222. Magnitudes 8 and 9, separation about 3.5 arcsec in p.a. 120 degrees. Photographic source catalogues measured combined images. 0 297085 Double star, photographic source catalogues measured combined image 0 297133 Seems to be double, with a separation of 2 to 3 arcsec. 0 298436 See remark to PPM 298437. 0 298437 Double star. Companion is PPM 298436. Components may be mixed up. 0 310971 Double star. Companion is PPM 310972. Components may be mixed up. 0 310972 Double star. Companion is PPM 310971. Components may be mixed up. 0 312674 Double star. Companion is SAO 219509. Components may be mixed up. 0 313226 Double star, identity of components unclear. Therefore the proper motion, both in PPM and in SAO, may be wrong. 0 314660 Double star. Companion is SAO 221478. Components may be mixed up. 0 320653 Double star. Companion is SAO 225845. Components may be mixed up. 0 322346 See remark to PPM 322347. 0 322347 In star cluster NGC 6231. Double star. Companion is PPM 322346. Components may be mixed up. 0 323229 Double star. Companion is SAO 228247. Components may be mixed up. 1 Page 17 - 0 323811 See remark to PPM 323812. 0 323812 Double star. Companion is PPM 323811. Components may be mixed up. 0 326265 Double star. Companion is SAO 230259. Components may be mixed up. 0 328272 Double star, the companion is PPM 328273. Not well separated, some photographic source catalogues measured combined images. 0 328273 See remark to PPM 328272. 0 330419 Seems to be a close double, components mixed up. 0 335814 Double star. Companion is PPM 335815. Components may be mixed up. 0 335815 See remark to PPM 335814. 0 339408 Eta Carinae complex 0 342157 Double star. Companion is SAO 241075. Components may be mixed up. 0 343102 Double star. Companion is SAO 241950. Components may be mixed up. 0 345433 Double star. Companion is SAO 227281. Components may be mixed up. 0 350797 Double star Dunlop 246, SAO 247739 and SAO 247738. Magnitudes 6 and 7, separation about 9 arcsec in p.a. 260 degrees. Photographic source catalogues measured combined images. 0 352179 Double star. Companion is PPM 352180. Components may be mixed up. 0 352180 Double star. Companion is PPM 352179. Components may be mixed up. 0 354885 30 Doradus nebula and cluster, NGC 2070 0 358676 Double star. Companion is SAO 251382. Components may be mixed up. 0 367144 Globular cluster Dunlop 62, NGC 362. 1 Page 18 - - - 6. List of Remarks on Individual Stars ====================================== 0 The following list gives, for each star included: The PPM number and a remark. In contrast to the Critical Comments these remarks are not of direct relevance to astrometry. 0 All stars included in this list carry the 'R' flag. 0 184482 Omikron Ceti, 2-10 mag 0 188303 Sigma Ori A, 4.0-6.0 mag 0 191848 T Hya, 7.3-13.8 mag 0 198814 Southern component to PPM 198815. 5 measured positions, somewhat discordant in declination. 0 218852 Spectral type K5 + M3ep 0 219584 Northern component of ADS 6553. Companion of similar brightness 5 arcsec to the south. 0 223226 U Hya, 4.8-5.9 mag 0 223323 The cross-identifications given are from SIMBAD data base. But according to SAOC this star is BD -13 3193 = HD 92677. 0 225675 R Crv, 5.9-14.0 mag 0 236273 Double star ADS 12699; a fainter companion lies about 5 arcsec to the north west. 0 239702 Double star. The companion is SAO 164830, about 5 arcsec to the north east. 0 243352 Double star. Companion is SAO 166652, 5 arcsec to the north. 0 259064 SAO 179935, brighter component of double ADS 8183. The fainter component is PPM 259065. 0 259065 Companion to PPM 259064 = SAO 179935. SAO data grossly wrong due to mixing of components. 0 283489 Double star. Companion is SAO 197558. 1 Page 19 - 0 295347 SU Sco, 11.5-14 mag 0 311594 variable, 3.4-6.2 mag 0 320951 Double star. Companion is SAO 226131. 0 321275 Double star. Companion is SAO 226443. 0 329505 Double star. Companion is SAO 231718. 0 339070 YZ Car, 9.0-10.7 mag 0 339090 UX Car, 8.1-9.1 mag 0 339405 SV Vel, 8.8-10.8 mag 0 344085 U Nor, 8.6-9.2 mag 0 349722 Double star. Companion is SAO 247198. 0 352298 Double star. Companion is SAO 248345. 0 354005 Double star. Companion is SAO 248985. 0 356979 SAO proper motion for this star is grossly wrong. 0 357553 Double star. Companion is SAO 250696. 0 358986 Southern component of an 8 arcsec pair. 0 359025 UU Mus, 9.4-10.3 mag 0 365147 Y Pav, 5.7-8.5 mag 0 377688 Double star. Companion is SAO 257158. 1 Page 20 - 7. Explanation of the machine-readable version of PPM South =========================================================== 0 The machine-readable version of PPM South contains 3 physical files. 0 The three files are: 0 - File 1: The text of this introduction to PPM South 0 - File 2: The catalogue as an easily readable table, 197179 records, in the same format as PPM (north). 0 - File 3: The catalogue in the format in which the preliminary version of PPM (north) was delivered in 1988. 0 The remainder of this chapter gives very short descriptions of these three files. It describes the formats of the files together with a short description of the contents. - The tables defining the individual files give the following information for each data item: 0 - name of the item (mnemonic) - position of the item within each record (first and last byte) - FORTRAN format - explanation - maybe a remark 0 In addition there is information on record length etc. at the top of each table. - File 1: The Introduction to PPM South + _____________________________________ 0 This is a text file, given in exactly the same format as the printed Introduction to PPM South. Record length is 133 bytes, but only 76 bytes are actually used (the remaining being always blank). This file can be used to produce printed versions of the introduction on any printer able to interpret the paper feed characters '1' (form feed), ' ' (single line feed), '0' (double line feed), '-' (triple line feed) and '+' (no line feed). Page headings, page numbering etc. appear as in the printed introduction. Just submit the file to your printer. The printed pages contain 66 lines at maximum. 1 Page 21 - File 2: PPM South as an easily readable table + _____________________________________________ 0 This is the main file giving the catalogue proper. Record length is 133 bytes. The stars are arranged in bands of 10 degrees width in declination. Within each of these bands they are ordered according to right ascension. This arrangement was also used in the SAO catalogue. You can use this file to produce a rough printed version of PPM South by just submitting it to a printer capable of printing 133 characters per line. No page headings, form feed characters etc. are included, of course. 0 PPM 2 - 7 I6 designation of the star in PPM South starting with No. 181732, see chapter 3. DM 10 - 18 A9 designation of the star in the Bonner Durchmusterung (for zones from -02 to -22 degrees) or in the Cordoba Durch- musterung (zones -23 to -89 degrees). Mag 20 - 23 F4.1 magnitude, see chapter 3. Sp 25 - 26 A2 spectral type, see chapter 3. R.A. 28 - 39 F2.0,1X,F2.0,1X,F6.3 Right Ascension for the equinox and epoch J2000.0, on the system of FK5, given in hours, minutes and seconds of time. Sign 42 - 42 A1 Sign of declination ('+' or '-'). Dec. 43 - 53 F2.0,1X,F2.0,1X,F5.2 Declination for the equinox and epoch J2000.0, on the system of FK5, given in degrees, minutes and seconds of arc. PMA 56 - 62 F7.4 proper motion in right ascension for epoch and equinox J2000.0, on the system of FK5, given in seconds of time per Julian year. PMD 64 - 69 F6.3 proper motion in declination for epoch and equinox J2000.0, on the system of FK5, given in seconds of arc per Julian year. N 71 - 72 I2 number of individual published positions used for the derivation of the position and proper motion given SA 74 - 75 F2.0 mean error of right ascension at the mean epoch of right ascension, multiplied by the cosine of declination, given in units of 0.01 seconds of arc. SD 77 - 78 F2.0 mean error of declination at the mean epoch of declination, given in units of 0.01 seconds of arc. SPMA 80 - 83 F4.1 mean error of the proper motion in right ascension, multiplied by the cosine of 1 Page 22 - declination, given in units of 0.001 seconds of arc per Julian year SPMD 85 - 88 F4.1 mean error of the proper motion in declination given in units of 0.001 seconds of arc per Julian year EPA 90 - 94 F5.2 weighted mean epoch of the measured positions used for the derivation of R.A. and PMA, given in years since 1900.0 EPD 96 - 100 F5.2 weighted mean epoch of the measured positions used for the derivation of Dec. and PMD, given in years since 1900.0 SAO 102 - 107 I6 designation of the star in the SAO Catalogue HD 109 - 114 I6 designation of the star in the Henry Draper Catalogue CPD 117 - 125 A9 designation of the star in the Cape Photographic Durchmusterung Flags 127 - 131 5A1 Five flags - possible values: 127 P problem case, preferably not to be used as astrometric reference star. 127 C a critical comment is given in the List of Critical Comments. Not to be used as astrometric reference star. 128 D double star, preferably not to be used as astrometric reference star. 129 - Not used, void for consistency with PPM (north). 130 F member of FK5, mostly bright stars, original FK5 data are given. 131 R a remark is given in the List of Remarks on Individual Stars. 131 V the magnitude is a photographic V magnitude copied from CPC-2. 0 Be careful not to miss the sign of the declination (byte 42) while transforming this formatted file into a numeric file on your computer. - File 3: The catalogue in the format of the preliminary PPM + __________________________________________________________ 0 File 3 gives a version of PPM South for equinox and epoch B1950.0, FK4 system (see items RA50, Dec50, PMA50 and PMD50 in the table below). It contains the J2000.0 version also. This file was added for the convenience of those users that received the preliminary PPM (north) on tape. To transfer File 3 to their home computer they can use exactly the same reading routine as for the preliminary PPM (north). 1 Page 23 - Record length is 138 bytes. 0 2 - 4 A3 3 characters 'PPM' PPM 5 - 10 I6 Mag 11 - 16 F6.1 Sp 19 - 20 A2 Flag 22 - 22 A1 problem flag, see description of File 2, byte 127 RA50 24 - 38 D15.8 radians Right ascension for equinox and epoch B1950, FK4 system Dec50 40 - 54 D15.8 radians Declination for equinox and epoch B1950, FK4 system PMA50 56 - 67 D12.5 radians/tropical century Proper motion in R.A. for equinox and epoch B1950, FK4 system PMD50 69 - 80 D12.5 radians/tropical century Proper motion in Dec. for equinox and epoch B1950, FK4 system R.A. 82 - 96 D15.8 radians Right ascension for equinox and epoch J2000, FK5 system Dec. 98 - 112 D15.8 radians Declination for equinox and epoch J2000, FK5 system PMA 114 - 125 D12.5 radians/julian century Proper motion in R.A. for equinox and epoch J2000, FK5 system PMD 127 - 138 D12.5 radians/julian century Proper motion in Dec. for equinox and epoch J2000, FK5 system - - References. =========== 0 Boss, B. (1936): General Catalogue of 33342 Stars for the Epoch 1950. Vols. I to V. Carnegie Institution of Washington, Washington 1936. 0 Bystrov, N.F., Polozhentsev, D.D., Potter, Kh.I., Zalles, R.F., Zelaya, J.A. and Yagudin, L.I. (1989): On the FOKAT catalog. Astron. Zh. 66, 425. 0 CMC (1985-1991): Carlsberg Meridian Catalogue La Palma, Numbers 1 to 5. Copenhagen University Observatory, Royal Greenwich Observatory and Real Instituto y 1 Page 24 - Observatorio de la Armada, San Fernando. 0 Corbin, T. (1991): International Reference Stars Catalog, Washington, US Naval Observatory, 1991. 0 Eichhorn, H. (1974): Astronomy of Star Positions, Frederick Ungar Publ. Co., New York. 0 Fricke, W., Schwan, H., Lederle, T. (1988): Fifth Fundamental Catalogue (FK5). Part I. The Basic Fundamental Stars. Veroeff. Astron. Rechen-Institut Heidelberg Nr.32. 0 IAU (1976): IAU Transaction XVI B, Reidel Publ., Dordrecht 1977. 0 Lieske, J. (1979): Precession matrix based on IAU(1976) system of astronomical constants, Astron. Astrophys. 73, 282. 0 Murray, C.A. (1983): Vectorial Astrometry, Adam Hilger Ltd., Bristol, UK. 0 Roeser, S. The System of the PPM Catalogue. Proc. IAU-Symp. 141 Inertial Coordinate System on the Sky. Ed.: J.H. Lieske and V.K. Abalakin. p. 469. Kluwer,Dordrecht, 1990. 0 Roeser, S., Bastian, U. (1991): PPM Star Catalogue, Astronomi- sches Rechen-Institut, Heidelberg, Vols. I and II, printed by Spektrum Akademischer Verlag, Heidelberg 0 Roeser, S. et al. (1993): The Construction of PPM South, in preparation. 0 Smith, C.A., Corbin, T.E. Hughes, J.E., Jackson E.S., Khrutskaya, E.V, Polozhentsev, A.D., Polozhentsev, D.D, Yagudin, L.I., Zverev, M.S. (1989): The SRS catalog of 20488 star positions: culmination of an international cooperative effort, in: IAU Symp. No. 141, Inertial Coordinate System on the Sky, Leningrad, Oct. 17-21, 1989. 0 Yagudin, L.I. et al. (1993): The FOKAT-S Star Catalogue, in preparation. 0 Zacharias, N., de Vegt, C., Nicholson, W., Penston, M., 1992: CPC-2 - the Second Cape Photographic Catalogue. Astron. Astrophys. 254, 394. 1 Page 25 - Acknowledgements ================ 0 This work was supported by Deutsche Forschungsgemeinschaft, Academy of Sciences of the USSR, Russian Academy of Sciences and Ukrainian Academy of Sciences in the framework of the collaboration project "Astrometric Star Catalogues". 0 We gratefully acknowledge help from our colleagues Wayne Warren, Heiner Schwan, Maria Erbach and Eberhard Roehl.