1. Jacobus Kapteyn (1851-1922)

2. Until the Second World War Astronomy was an Optical Science: all observations were made with instruments working in the visible (with usually the eye as a detector). As a result of modern technology, this has changed enormously.

5. Gamma-Ray (CGRO) X-Ray (HEAO-1) Infrared (IRAS) Radio (various places) Visual (Lund)

6. X-rayUVVisual IR (IRAS) Radio (VLA)

7. X-rayVisible IR (ISO) Radio

8. Very few people in our field can still afford to work without the Internet. Astronomers are using it all the time for the following things: 1 Communication (email) 2 To obtain all kinds of Software 3 To retrieve observational data from telescope archives (satellites and ground-based) 4 Teaching 5 Publish their preprints and papers 6 Read and obtain journals in astronomy 7 Run CPU-intensive work at computers elsewhere 8 Hear the most recent results 9 To obtain their observations from satellites and remote observing (service). 10 Etc.

9. Available at present:  Satellites (HST, Chandra, IUE, IRAS, etc.)  Ground-based telescopes - Survey Telescopes (2MASS, POSS, etc.) - General Observer Telescopes (ESO, La Palma, UKIRT, CFHT, JCMT, VLA)  Object-oriented - Galaxies: NASA Extragalactic Database (NED); LEDA - Nearby Galaxies: Hypercat (specialised) - Stars: SIMBAD

10.  Most Popular Journals (including back-issues until 19 th century): NASA ADS  Electronic preprint server (ArXiv.org)  Hubble Space Telescope publish relations service

11. Very often used:  Data Reduction and Analysis: AIPS, ESO-MIDAS, IDL, IRAF, PROS, STARLINK, STSDAS  Document Preparation: LaTeX, TeX  Modelling: NEMO, CLOUDY, DUSTY, TINYTIM  Subroutine Libraries: FITSIO, NAG, Numerical Recipes  Math Routines: Maple, StatCodes  Utilities:...

12. References: The electromagnetic spectrum: http://www.ipac.caltech.edu/Outreach/Multiwave/ (at IPAC) Data Archives: Satellites: reachable through STScI ( http://archive.stsci.edu/ ) ESO: http://archive.eso.org/ La Palma: http://archive.ast.cam.ac.uk/ingarch/ UKIRT: http://archive.ast.cam.ac.uk/ukirt_arch/ CFHT: at CADC (http://cadcwww.dao.nrc.ca/) together with a lot of Other archives VLA: http://www.aoc.nrao.edu/vla/vladb/ Etc. Object oriented: Simbad (stars): http://simbad.u-strasbg.fr/Simbad LEDA (nearby galaxies): http://leda.univ-lyon1.fr/ Hypercat (nearby galaxies): http://www-obs.univ-lyon1.fr/hypercat/

13. References: Journals in Astronomy: all on NASA ADS ( http://adswww.harvard.edu/index.html ) This site has several mirrors across the world. Preprints: http://arXiv.org/ also with several mirrors Public Outreach: http://oposite.stsci.edu/ (very nice!) Software in Astronomy: a large amount of software can be found at the Linuxastro site: http://bima.astro.umd.edu/nemo/linuxastro/