Pictures

Hubble Space Telescope

http://hubblesite.org/newscenter/

2MASS Messier Catalog Gallery
http://www.ipac.caltech.edu/2mass/gallery/messiercat.html

Astrophysical Data System (NASA ADS)
http://adswww.harvard.edu/

Anglo-Australian Observatory Astronomical Images
http://www.aao.gov.au/images.html/

Astronomy Picture of the Day (GSFC)
http://antwrp.gsfc.nasa.gov/apod/astropix.html

Galaxy Cluster Mug Shots
http://www.astr.ua.edu/white/mug/cluster/clusters.html

NOAO Image Gallery
http://www.noao.edu/image_gallery/

Planetary Photojournal NASA
http://photojournal.jpl.nasa.gov/

SDSS Art shots
http://www.sdss.org/data/artclick/artframe.htm

SDSS Image Gallery
http://www.sdss.org/gallery/index.html

UA Astronomical Image Galleries
http://crux.astr.ua.edu/choosepic.html

VLT Astronomical Images - Index
http://www.eso.org/outreach/info-events/ut1fl/astroimages.html

Observatories/Missions

Anglo-Australian Observatory
http://www.ast.cam.ac.uk/AAO/

Carnegie Observatories
http://www.ociw.edu/

CFHT
http://www.cfht.hawaii.edu/

Chandra X-ray Observatory Center
http://chandra.harvard.edu/

CTIO
http://www.ctio.noao.edu/

CWRU Astronomy Department
http://burro.astr.cwru.edu/dept/

Dominion Astrophysical Observatory
http://www.hia.nrc.ca/facilities/dao/

ESA Hubble Information Centre
http://sci.esa.int/hubble/index.cfm

European Southern Observatory
http://www.eso.org/

European Space Agency
http://sci.esa.int/science-e/www/area/index.cfm?fareaid=1

Gemini Observatory
http://www.gemini.edu/

Harvard-Smithsonian Center for Astrophysics
http://cfa-www.harvard.edu/

Isaac Newton Group of Telescopes
http://www.ing.iac.es/

Indiana University Astronomy Department
http://astrowww.astro.indiana.edu/

JWST - Gallery - Telescope
http://jwstsite.stsci.edu/gallery/telescope.shtml

Kitt Peak National Observatory
http://www.noao.edu/kpno/

Konkoly Observatory
http://www.konkoly.hu/

Lick Observatory
http://www.ucolick.org/

Lowell Observatory
http://www.lowell.edu/

Lund Observatory
http://www.astro.lu.se/

McDonald Observatory
http://www.as.utexas.edu/mcdonald/mcdonald.html

Mount Stromlo and Siding Spring Observatory
http://msowww.anu.edu.au/

Mount Wilson Observatory
http://www.mtwilson.edu/

NASA
http://www.nasa.gov

NASA Infrared Telescope Facility
http://irtf.ifa.hawaii.edu/

NOAO
http://www.noao.edu/

NRAO
http://www.nrao.edu/

Palomar Observatory
http://astro.caltech.edu/observatories/palomar/public/index.html

SIRTF
http://sirtf.caltech.edu/

Sloan Digital Sky Survey
http://www.sdss.org/

SOFIA
http://sofia.arc.nasa.gov/

South African Astronomical Observatory
http://www.saao.ac.za/

Steward Observatory, University of Arizona
http://www.as.arizona.edu/

Subaru Telescope, NAOJ
http://www.subarutelescope.org/

Two Micron All Sky Survey (2MASS)
http://www.ipac.caltech.edu/2mass/

UK Schmidt Telescope
http://www.aao.gov.au/ukst/

United States Naval Observatory
http://www.usno.navy.mil/

Vatican Observatory
http://clavius.as.arizona.edu/vo/

Very Large Array
http://www.aoc.nrao.edu/vla/html/VLAhome.shtml

Very Large Telescope
http://www.eso.org/projects/vlt/

WIYN
http://www.noao.edu/wiyn/

Yerkes Observatory
http://astro.uchicago.edu/yerkes/

 
Miscellaneous

American Astronomical Society (AAS)
http://www.aas.org/

Astronomical Society of the Pacific (ASP)
http://www.astrosociety.org/

Bad Astronomy (Phil Plait)
http://www.badastronomy.com/bad/index.html

Digital Sky
http://www.cacr.caltech.edu/SDA/digital_sky.html

International Dark-Sky Association
http://www.darksky.org/ida/ida_2/

SEDS
http://www.seds.org/

USNO Data Services
http://aa.usno.navy.mil/AA/data/