Bruce telescope
The Bruce telescope is a special, powerful double astrograph of the State Observatory Heidelberg-Königstuhl (Baden-Württemberg), which the American philanthropist Catherine Wolfe Bruce (1816–1900) financed around 1895 at the request of Max Wolf of the observatory. Bruce dedicated a second, even larger instrument in 1900 to the Yerkes Observatory in the USA.
When scientific astrophotography was also able to record faint celestial objects in the last quarter of the 19th century , Wolf first developed such a photographic double telescope for his private observatory in 1890 . He began the visually difficult to observe dust fog to photograph the Milky Way with very long exposure times. Just a few years later, with the Bruce telescope, he made groundbreaking discoveries about the structure of the Milky Way and numerous previously unknown light and dark nebulae.
The two cameras mounted on a long focal length guide telescope (see picture) have an aperture of 40 cm and a focal length of 2 meters - both for dimensions that were unfamiliar at the time. All three instruments track the daily rotation of the starry sky with high precision by a common equatorial mount . The advantage of double photo telescopes is threefold: on the one hand, the long-exposure sky recordings are accelerated, on the other hand, simultaneous recordings in different color areas are possible. In addition, by comparing the photo plates in the so-called blink comparator, incorrect blackening in the film emulsion can be detected.
An even larger instrument of this type with a 61 cm aperture was financed by Bruce of the Yerkes Observatory in the USA. It has also contributed a lot to research in galactic astronomy , particularly through the work of Edward Emerson Barnard . Barnard came to Heidelberg in 1899/1900 for preliminary studies for this telescope.
Such double astrographs as the two Bruce telescopes were widespread until around 1980, but then became less important due to the shorter exposure times of CCD sensors and the first successful space telescopes .
literature
- GD Roth: Astronomie-Geschichte , Kosmos-Verlag, Stuttgart 1987
- Max Wolf: The nebulae at the pole of the Milky Way . Publ. Astrophysical. Institut Königstuhl-Heidelberg, Volume 1, pp. 125–176, Heidelberg 1902.