Introduction
Design
Telescope Control System
CCD camera
Brorfelde Image Acquisition System
Guide camera
Input catalogue
Main specifications
Early plans of astronomical equipment at the Brorfelde Astronomical Observatory include building of a Schmidt telescope at the observatory workshop.
The following main data was decided by Professor Bengt
Strømgren in the autumn 1958:
Diameter of main mirror 75 cm, free opening 50 cm, focal
length 150 cm and with a "on/off" 15░ objective prism.
The design of the telescope started in 1961, done by the head of the mecanical workshop Mr.Poul Bechmann.
Soon after the work started, mostly in the observatory mecanical workshop, but some special and bigger parts for telescope,(and the Ø 6.8 Mtr. steel dome) was ordered from outside, e.g. optics, worm & wormwheels and bigger welded parts of the telescope and dome.
The concrete/stone part of the dome was designed by Professor Gotlib, and contain on the observing floor a observing room, a darkroom and a small "hot" room for the observer. In the basement toilet, main gears,motors and refrigerator for photografic plates is situated.
The telescope was installed in the dome in spring 1996 and soon after the test started.
Because of serius troubles between the main mirror material
(F2 glass) and aluminium it was at last desided to buy another
mirror made of a better material.(Zeoudur)
The new mirror has a diameter of 77 cm, the free opening is,
because of a deform corrector, cut to Ø45 cm.
After a long break, the telescope was tested during the season 1973/1974, and finally in 1975 the regular obsevations could start, using 150 x 150 x 1 mm photographic plates, with a field of 5░.2 on which it vas possible to reach stars down to mag.18.5.
During the years 1975 to 1991 the telescope was used continuously - observing many different fields, mostly direct photographic fields, but also a lot of objective prism exposures have been obtained.
The telescope has in the same period been used for education of students, who has done small projects on the telescope.
A modification in 1989 - 1990 include a complete TCS (Telescope Control System) with new direct drive motors, gears and encoders in Ra. and Dec.
The total number of photographic plates kept in the Brorfelde Schmidt plate archive from the period are about 2000 (excl. a lot of test/focus plates) (The archive is still in Brorfelde, placed in the main building basement)
The plates are also registered in "Wide-Field Plate Database" (WFPDB in SOFIA)
In 1991 it was again desided to modify the telescope, and during 1991/1992 the telescope was equipped with a JPL GRAF/Cassini 1024 x 1224, 12 micron pixel CCD camera which replaced the photographic system.
The CCD camera are controlled and operated by a Linux based PC program BIAS (Brorfelde Image Acquisition System)
Finally a CCD based guide camera (BAOCAM) was mounted on one of the guide telescopes on a x-y carrige.
In december 1992 the new system start to operate and has continued since.......
The telescope operate in a service mode and observers are requested to make a input catalogue .
Finally a lot of the most important main specifications for The Brorfelde Schmidt Telescope are listed.(updated late in 1995.)
Brorfelde 10/10/1996
Karl Augustesen (kalle@astro.ku.dk)
(See also NBI f. AFG )
Last updated January 23, 1997 by norup@astro.ku.dk