81 ON-LINE SERVICES AT CDS FOR DISTRIBUTION OF HIPPARCOS DATA D. Egret, F. Ochsenb ein, F. Genova CDS, Observatoire astronomique de Strasb ourg, 67000 Strasb ourg, France This is done through the development of a set of com- ABSTRACT plementary information services see e.g. Egret et al. 1995, Genova et al. 1996. CDS has b een implementing the following functional- ities for a timely distribution of Hipparcos and Tycho The common gateway to all these services is pro ducts, when they are released, in June 1997: the CDS home page on the World-Wide Web at http://cdsweb.u-strasbg.fr/ 1. Access will be given to the Hipparcos cata- We describ e here how these services can b e used for logues ESA 1997 through the VizieR catalogue gaining access to Hipparcos and Tycho data and cat- browser, allowing queries byany of the catalogue alogues. elds. A frequent use of the system will b e the extraction of Hipparcos or Tycho records related to a given area of the sky, de ned by its co ordi- nates or by the name of a central ob ject this last 2. ACCESS TO INDIVIDUAL RECORDS functionality making use of the SIMBAD name THROUGH RELATIONAL QUERIES resolver. 2. Access will be given to Hipparcos result cata- logues through the `Astronomer's Bazaar' ftp Access to Hipparcos and Tycho data will rst be access to the complete les. The system sup- provided through the new `VizieR' catalogue service p orts the transfer of compressed les in order to which allows the retrieval of individual data records optimize use of network bandwidth. from selections on table columns, or from p osition or ob ject name. 3. The Hipparcos and Tycho Catalogues will b e in- cluded within SIMBAD as so on as p ossible after VizieR Ochsenb ein 1997, the CDS service for astro- the June 1997 release date. The work has al- nomical catalogues, is the result of a joint e ort b e- ready b een prepared with the Input Catalogues; tween the Strasb ourg astronomical Data Centre and nevertheless, it will take some time b efore a the Information Systems Division of the Europ ean number of inconsistencies are investigated and Space Agency ESA{ESRIN in order to provide the solved. astronomical community with a dedicated to ol for retrieving astronomical data listed in published cat- 4. The Aladin interactive sky atlas, in its nal de- alogues and tables. velopment phase, will also supp ort access to the Hipparcos and Tycho data for photometric and astrometric calibration and for overlays on digi- Access to Hipparcos and Tycho result catalogues tized sky images. through VizieR will start with Hipparcos and Tycho main catalogues, as so on as they are released, and will also include Annex les for Double and Variable In the future, as CDS services continue to evolve, stars and Solar system Annexes. Functionalities in- more links will b e added b etween these services and clude selection of individual records, for a given area the asso ciated bibliographic services, allowing yet of the sky,orby parameter ranges on any eld. Full more p owerful supp ort for the usage of Hipparcos or do cumentation of the catalogues will b e available on- Tycho data pro ducts. line. Example: Extraction of Hipparcos or Tycho records Key words: Catalogues; CDS. for stars brighter than 9.0, having go o d astrometric quality,inagiven area of the sky, de ned by co ordi- nates or name of a central ob ject this last function- ality making use of the SIMBAD name resolver. 1. INTRODUCTION The interface is based on the use of World-Wide Web forms. The reference numb er for the Hipparcos and The ob jective of the Strasb ourg astronomical Data Tycho Catalogues ESA 1997 in the CDS system is Centre CDS is to provide on-line data and infor- I/239. mation for the world-wide astronomical community. 82 The release date for this service is Tuesday 17 June astronomical ob ject, thus o ering a unique p ersp ec- 1997, at the following address: tive on astronomical data. This is done through a http://vizier.u-strasbg.fr/ careful cross-identi cation of ob jects from catalogues, lists, and journal articles. The abilityto gather to- gether any sort of published observational data re- lated to stars or galaxies has made SIMBAD a key 3. ACCESS TO THE COMPLETE FILES FOR to ol used worldwide for all kinds of astronomical FTP TRANSFER studies. SIMBAD includes bibliographic references to pap ers citing the ob jects, thanks to a bibliographic survey covering the astronomical literature since 1950 Access to all Hipparcos and Tycho result cata- for stars, and since 1983 for extragalactic ob jects. logues distributed by ESA on CD-ROMs except The data base is kept up-to-date on a daily basis, as Epoch Photometry will b e provided through the `As- the result of the collab oration of CDS with bibliog- tronomer's Bazaar'. raphers in the Institut d'Astrophysique de Paris and the Paris and Bordeaux observatories Laloe 1995. The Astronomer's Bazaar Egret & Ochsenb ein 1994 isaWorld-Wide Web service allowing: In preparation for the release of Hipparcos data, a sp eci c e ort has b een undertaken at CDS in recent years to fold into the data base large astronomical to query the full list of available catalogues and stellar catalogues, together with their sp eci c identi- tables, bykeyword, or in browse mo de, in order ers and measurements, such as the PPM catalogue the select the relevant les, Roser & Bastian 1991. to display the corresp onding do cumentation, Functionalities include access to cross-identi cation, and to retrieve the complete electronic les measurements and complete bibliography for individ- eventually compressed, in ASCI I or FITS for- ual ob jects, called by name, or for lists of ob jects mat, from the anonymous ftp space of the CDS selected by criteria. server. Examples: More than 2000 catalogues and tables, for a total of several Gigabytes of data are currently available Selection of all A-typ e stars observed with the through this interface. International Ultraviolet Explorer IUE and measured by Hipparcos. Functionalities include the transfer of complete ASCI I les using the p opular File Transfer Proto- Search for recent bibliography of all RR Lyrae col ftp. The system supp orts the transfer of com- stars observed by Hipparcos. pressed les in order to optimize use of network band- width. Flexible Image Transp ort System FITS for- Several interfaces are available: World-Wide Web mat may b e generated on the y. forms, X-Window client, line-by-line command inter- face. Warning: some of the les are very large! When p ossible, CD-ROMs of the Hipparcos mission, dis- Hipparcos stars can b e found under their HIC or HIP tributed by ESA, should be preferred, as more ap- numb ers, Tycho stars under their TYC numb ers. propriate transfer media, for the large les of the Hipparcos and Tycho Catalogues. Release dates: HIC numb ers are already included in SIMBAD, and consequently integration of HIP stars The reference numb er for the Hipparcos and Tycho is approximately 99 p er cent complete. Gradual in- Catalogues ESA 1997 in the CDS system is I/239. clusion of Tycho entries will start in June 1997. The work has already b een prepared with the Tycho In- The release date for this service is Tuesday 24 June put Catalogue, and with the cross-identi cation of 1997, at the following address: the Tycho Catalogue with several ma jor catalogues http://cdsweb.u-strasbg.fr/Cats.html see Egret & Fabricius 1997; nevertheless, it will take some time b efore a numb er of inconsistencies are in- Mirror copies are also available at the NASA Astro- vestigated and solved. nomical Data Center: http://adc.gsfc.nasa.gov, and at the National Astronomical Observatory in SIMBAD is available at the following address: Tokyo: http://adac.mtk.nao.ac.jp http://simbad.u-strasbg.fr/ 4. ACCESS TO COMPLEMENTARY 5. ACCESS TO RELATED IMAGES OF THE INFORMATION FOR THE OBJECTS DIGITIZED SKY The SIMBAD data base is a powerful to ol for pro- The `Aladin' interactive sky atlas, now in its nal de- viding complementary information, when available in velopment phase see e.g. Bonnarel et al. 1997, will the published literature, for astronomical ob jects ob- include links to the Hipparcos and Tycho Catalogues. served by the Hipparcos space astrometry mission. The sp eci city of the SIMBAD data base see e.g. Aladin is a new pro ject nearing completion which al- Egret et al. 1991 is to organize the information p er lows the user to visualize on his/her own workstation 83 digitized images of any part of the sky,tooverlay en- REFERENCES tries from astronomical catalogues or user data les, and to interactively access the related data and in- Bonnarel, F., Ziaeep our, H., Bartlett, J.G., et al. formation from the SIMBAD data base for all known 1997, in IAU Symp. 179, New Horizons from ob jects in the eld. Multi-Wavelength Sky Surveys, in press Egret, D., Fabricius, C., 1997, ESA SP{402, this vol- The data base currently includes the rst Digitized ume Sky Survey DSS-I pro duced by the Space Telescop e Egret, D., Ochsenb ein, F., 1994, CDS Inform. Bull., Science Institute, covering the complete sky,asaset 44, 57 of slightly compressed images. Images of the second epoch survey DSS-I I; Lasket et al. 1996 are grad- Egret, D., Wenger, M., Dub ois, P., 1991, in ually b eing included.