Description: The Multi-purpose Photometer (MPF)
was built by J. Tinbergen at Leiden University. In this instrument light
passes through an optional calibrator and is focussed on to a single or
double diaphragm; the latter is for sky-chopping. After passing through
an optional polarizer for linear polarimetry, the beam continues through
two optional neutral density wedges and three optional neutral density
filters to the collimator and an electro-mechanical shutter. The dichroic
beam-splitter assembly yields up to six beams; three beams between 3000
and 6000 Å, the other three between 4500 and 9000 Å. Each of
these beams is then split again, normally by a neutral beam-splitter, to
form a pair for Hß type photometry. The final beams pass through
three-position filter slides and Fabry lenses to the photocathodes.
Publications: research or technical papers, etc.