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Astronomical observatories

The research presented on these pages is based on observations conducted with a number of telescopes around the world. As explained based on the example of spiral galaxies with gaseous halos, observations at different wavelengths can provide us with various pieces of information. These we combine, like in a jigsaw puzzle, in order to gain a panchromatic view of astronomical objects. The observations come from telescopes that specialize in various types of observations. Mostly the specialization is based on their capability to collect photons of particular wavelengths. But there are also other specializations, for example for achieving the highest possible angular resolution. In the following, the observatories used for my research are presented, grouped by the wavelength regimes they work in. Some information is also provided on observatories in other wavebands or that I have not (yet) used for my research, so as to give a somewhat more complete picture. However, it is quite evident that one cannot provide a complete list of all observatories in this framework.

The subdivision of the electromagnetic spectrum into wavelength regimes is in part just a matter of convention, but there are also natural causes for a logical subdivision. The most important determining factor in this subdivision is the transparency of our atmosphere:

One can see that the atmosphere is transparent in only two wavebands: the optical and the radio regime. There is another band near 10 micrometer wavelength (which is in the so-called "mid-infrared" regime) and a few more narrow windows down to 1 micrometer at which also more than 90% of the incoming light can pass through.

In using specialized telescopes for observations of radiation with various wavelengths we are following a good example established by mother nature: The adaptation of our eyes to the maximum of solar light emission, which lies in the area that we call (quite suggestively) "visible light" (or also "optical light"). One can truely consider the wavebands in which the atmosphere is transparent "windows" to the Universe through which we are looking.

Conversely, the plot above makes it evident that most cosmic radiation does not penetrate our atmosphere to reach the ground. This is very fortunate for us, because if energetic UV or even X-ray emission could reach the Earth's surface, there would be no life. Therefore, atmospheric opacity is a blessing for mankind; but it is a hassle for astronomers! In the wavebands where our atmosphere is opaque we cannot observe the sky from the ground - which is the reason for building costly satellites to complete our view of the sky from above the atmosphere in wavebands that would otherwise remain unaccessible to us, but where we can gain valuable new information that is not available from observations conducted from the ground. The following table lists observatories according to the wavebands they work in. For basic information on the astronomical research conducted in the various wavebands, please refer to the page on multi-waveband observational astronomy.

Disclaimer: Please note that the selection of observatories presented here in pictures is by no means systematic or ranked in any way. Most of those shown in photos I have visited and the photos were taken by myself. Ground-based observatories that I have not visited yet are normally listed without pictures. And even then, there are lots more and I cannot do them all justice (neither can I visit them all...).