27 research outputs found
Preadvies voor herstel en ontwikkeling van vochtige bossen op de pleistocene zandgronden
Dit preadvies geeft inzicht in de sleutelprocessen en factoren die bepalend zijn voor behoud en ontwikkeling van natuurwaarden in vochtige bossen. Ook zijn de mogelijkheden in kaart gebracht om via herstelbeheer, regulier beheer en omvormingsbeheer te komen tot herstel van natuurwaarden in het geval sleutelprocessen en factoren verminderd of niet meer werkzaam of aanwezig zijn
UV and EUV Instruments
We describe telescopes and instruments that were developed and used for
astronomical research in the ultraviolet (UV) and extreme ultraviolet (EUV)
regions of the electromagnetic spectrum. The wavelength ranges covered by these
bands are not uniquely defined. We use the following convention here: The EUV
and UV span the regions ~100-912 and 912-3000 Angstroem respectively. The
limitation between both ranges is a natural choice, because the hydrogen Lyman
absorption edge is located at 912 Angstroem. At smaller wavelengths,
astronomical sources are strongly absorbed by the interstellar medium. It also
marks a technical limit, because telescopes and instruments are of different
design. In the EUV range, the technology is strongly related to that utilized
in X-ray astronomy, while in the UV range the instruments in many cases have
their roots in optical astronomy. We will, therefore, describe the UV and EUV
instruments in appropriate conciseness and refer to the respective chapters of
this volume for more technical details.Comment: To appear in: Landolt-Boernstein, New Series VI/4A, Astronomy,
Astrophysics, and Cosmology; Instruments and Methods, ed. J.E. Truemper,
Springer-Verlag, Berlin, 201