The High-Speed UBVRI Photometer MCCP
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Das MCCP am 0.8m Teleskop auf dem Wendelstein.
For precise multicolour aperture photometry of fast variable phenomena
the Multi-Channel Multi-Colour Photometer
MCCP has been developed.
This instrument uses three optical fibers which are positioned by
computer control onto three light sources
(e.g. the variable star, a nearby comparison and the sky background)
in the focal plane of the telescope.
The fiber ends repectively form the entrance slits of three
prism-spectrographs.
The individual spectra are projected on fiber bundels which allow to
select 5 overlapping broad band regions corresponding to the
Kron-Cousins UBVRI colours.
The colour channels of each lightsource feed 5 photon counting
photomultipliers which are thermoelectrically cooled to -20 degree
Celsius.
The output signals are recorded by a real time multi-tasking VME-Bus
computer system.
This measuring method yields simultaneous UBVRI data of three light
sources with a maximum time resolution of 1 ms.
Peripheric devices include an on-line graphics system which allows to
monitor selected light curves and an autoguider system which controls
the star centering in the fiber diaphragms.
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Schematic drawing of th MCCP
Specifications of the MCCP:
Simultaneous measuring channels: | 3 |
Diameter of measuring diaphragms: | 0.6/0.8/1.0 mm |
Simultaneous colour channels: | 3 x UBVRI |
Detectors: | 15 HAMAMATSU Photomultipliers |
Time resolution: | <= 1 ms |
Max. count rate per channel: | <= 2 10E5 cts/s |
Typical dark count rates: | <= 5 cts/s |
Spectral range: | 350 - 900 nm |
App. brightness range: | V = 8...15 mag.( at 80cm telescope) |
For further details see:
Barwig,H., Schoembs,R., Buckenmeyer,C., 1987:
"A multi-channel multi-colour photometer for high time resolution",
Astron. Astrophys., 175, 327.
Mantel,K.H., Barwig,H., 1994:
"Multichannel-Multicolour Photometry - experiences from a long term
observing campaign",
in Proc. of the NATO Advanced Research Workshop on "The Impact of
Long-Term Monitoring on Variable Star Research", November 1993, Ghent,
Belgien, NATO ASI series C436, eds. C.Sterken, J.de Groot, 329.
Barwig,H., Mantel,K.H., Kiesewetter,S., 1998:
"Impact of Fiber Optics on Photometry - Design of two High-Speed
Multichannel Instruments", in Proc. of the meeting held in Puerto
de la Cruz, Canary Islands, Spain, 2-4 December 1997 on
"Fiber Optics in Astronomy III", eds. S.Arribas, E.Mediavilla,
F.Watson, Astronomical Society of the Pacific, Conference Series, Vol.
152, 320.
Last revision: July 2001
email: Heinz Barwig (hbarwig@usm.uni-muenchen.de)