4.1 Optical archives
Several observatories archive routinely their data and make it available to the community. Most of these catalogs have a name resolver data query.
The ESO archive (http://archive.eso.org) contains all the NTT observations since April 1, 1991. Data can be requested after one year from the observation date. The data is stored uncalibrated, so remember to request the calibration files as well.
All infrared and optical images obtained with CFHT since late September 1992 are archived (http://cadcwww.dao.nrc.ca/cfht/menu.html). After the proprietary period of 2 years they are widely available through the WWW interface.
Around 430,000 observations obtained with the William Herschel Telescope, the Isaac Newton Telescope and Jacobus Kapteyn Telescope are archived by the Isaac Newton Group (http://ing.iac.es). The proprietary time for these data is one year.
The Save the Bits program started at NOAO in 1995. The images are stored in ExaByte tapes in FITS format (http://www.noao.edu). The proprietary period for KPNO and CTIO data is 18 months.