The Astronomical Institute Utrecht houses the astrophysics research group of Utrecht University. Its program revolves predominantly around all aspects of observational and theoretical stellar research. The objects investigated range from studies of the nearest star, the Sun, to distant star clusters, and from young stars, to the end products of stellar evolution, supernova remnants, white dwarfs, and neutron stars. Extragalactic research is incorporated through a close collaboration with SRON, Netherlands Institute for Space Research.

The institute has a long history that dates back to the founding of an observatory in Utrecht in 1642, and among its members it counts famous scientists as Pieter van Musschenbroek (1692-1761), inventor of the first capacitor, and Marcel Minnaert (1893-1971), who was responsible for the famous Utrecht Atlas of the solar spectrum, and who invented the curve of growth method for doing quantitative spectroscopy. One of its most famous alumni is Henk van de Hulst (1918-2000), who as a student at Utrecht University made his seminal calculation of the 21 cm hydrogen transition, which is the most widely used transition used in radio astronomy.

Originally astronomical research was done in the center of Utrecht, and since 1854 it was housed in Observatory the "Sonnenborgh", built on top of an bastion and part of the defense wall around the city center of Utrecht.  Since 1987 the institute is situated at the University campus, Uithof. The rich history of stellar research in Utrecht can be seen in the old observatory "Sonnenborgh".

You are looking at the new web presence of the Astronomical Institute Utrecht, launched on November 1, 2009. For reference purposes, the old web site remains accessible at: http://www.astro.uu.nl/siu/.