Some useful astronomical links

Thousand and one catalogs in Strasbourg: CDS

The first attempt at a systematic collection of information about astronomical objects and query them in an easy way was done at the Centre des Donneés Astronomiques de Strasbourg (CDS)
(http://cdsweb.u-starsbg.fr/CDS.html). Since 1983 the CDS is embarking in a project to "collect, homogenize, distribute and preserve [on-line] astronomical information" (F. Genova, personal communication). The information is not raw data but metadatabases created from observing logs, catalogs, papers and images.

The services available at the CDS include:

• SIMBAD


• vizieR


• Aladin
  
• Dictionary of Astronomical Nomenclature


• "Information & On-line Data in Astronomy" (Egret & Albrecht 1995) complementary on-line version


• Star*s pages


• Abstracts


• ADS mirror


• Opacity project atomic data


• CFHT documentation


• IUE ULDA (French host)

SIMBAD
SIMBAD (Set of Identifications, Measurements, and Bibliography for Astronomical Data) can be accessed from the WWW (at the CDS --
http://cdsweb.u-strasbg.fr/simbad.html or at the US node http://www.cfa.harvard.edu/simbad), via telnet or e-mail. SIMBAD has 5,000 individual user accounts in 55 countries. An IP control password will be available soon that will allow institutional access to the service. As it is necessary to have an account, prospective users in the US (charges assumed by NASA) should send a request to simbad@cfa.harvard.edu. Others (European charges are covered by ESO and ESA) should enquire at their libraries or question@simbad.u-strasbg.fr.

SIMBAD contains more than 1.5M objects, more than 4.3M identifiers and more than 95k references from 90 journals (since 1950 for stars and since 1983 for extragalactic objects). The data included in SIMBAD evolves constantly as the measurements are updated and more references included daily (in 1994 there were 500 new entries per month).

Its most important characteristic is the cross-identification of the objects. SIMBAD contains a cross-index to several hundred astronomical catalogs and logs of space observatories.

It can be queried by name, coordinates or reference code. SIMBAD is the result of a cooperative effort among several institutions. The bibliography is compiled by the Institute d'Astrophysique in Paris and the Bordeaux Observatory; the catalogs by the Observatoire du Midi Pyrenées, the Paris and Besançon Observatories, Astronomisches Recehen-Institut (Heidel berg) and Institute for Astronomy of the Russian Academy of Sciences; correction to the databases are made by the Montpellier Observatory.

As was the case with NED, SIMBAD can also be used in a client/server mode to retrieve essential information on objects to be included in other programs.

What started with SIMBAD was continued with an impressive collection of browsers and catalogs, a true Astronomer's Bazaar
(http://cdsweb.u-strasbg.fr/Cats.html).

VizieR
VizieR (http://cdsweb.u-strasbg.fr/cgi-bin/VizieR) is a collection of around 2400 catalogs (1800 already available on-line) that can be queried either by the specific entry on it, by author name, by keywords, wavelen gth of interest and the mission or through a map based on a neural network analysis of the keywords associated to the catalogs. With Hipparcos on line since May 1997 the use of VizieR has increased exponentially.
VizieR is a cooperative endeavor among the CDS, the Astronomical Data Center in the US, Russian Academy of Sciences Institute for Astronomy (INASAN), National Astronomical Observatory of Japan, the Beijing Observatory in China and the Indian Inter-University Centre for Astronomy and Astrophysics (IUCAA). The CDS created a standard that is followed by these data centers and (most importantly!) by the journals in the publication, presentation and distribution of the data.

Future enhancements include links to SIMBAD and other external archives.

Aladin
Aladin is an interactive sky atlas that includes images from the Digitized Sky Survey, and for some regions (the LMC, SMC and galactic plane for example) special images with 1" resolution. It also includes a cross identification tool of the objects in the image. Aladin is only available via and X-term version, a WWW port is being developed at the moment.

Dictionary of Nomenclature of Astronomical Objects
The Dictionary of Nomenclature of Astronomical Objects, an up-to date electronic version of the "Second reference dictionary of the nomenclature of celestial objects" (Lortet et al. 1994)
(http://simbad.u-stasbg.fr/cgi-bin/Dic)is a SIMBAD by-product.

Information & On-line Data in Astronomy
At the CDS there is an on-line version of the book "Information & On-line Data in Astronomy" (http://cdsweb.u-strasbg.fr/data-online.html) (Egret & Albrecht 1995). Each section of the book has links to most of the archives and centers of interest.

StarPages
StarPages (http://vizier.u-strasbg.fr/starpages.html) a collection of directories, dictionaries and astronomical databases:
- Starheads (http://vizier.u-strasbg.fr/starheads.html) list with around 4000 astronomers world wide
- StarWorlds (http://vizier.u-strasbg.fr/starworlds.html): lists more than 6000 organizations world wide
- StarBits ( http://vizier.u-strasbg.fr/starbits.html): lists of around 115,000 acronyms and abbreviations .