Six-Channel uvby-H_β Photometer at the Danish 1.54-m

The Six-Channel uvby-H_β Photometer was mounted on the instrument adaptor at the Cassegrain focus of the Danish 1.54-metre telescope in the late 1980s. The adapter housed a field viewer with a field of 3.5 × 3.5 arcminutes² and an integrating TV system. The TV system was also used via a periscope system for centring the star in the photometer diaphragm.

The Six-Channel uvby-H_β Photometer was a rebuilt version of the H_β Photometer together with the Four-Channel uvby Photometer. It included the H_β section and filters were added to make it very similar to the Four-Channel uvby Photometer that was mounted at the Cassegrain focus of the Danish 0.5-metre telescope.

Six diaphragms with diameters of 110, 32, 16, 10, 7 and 4 arcseconds were available to the photometer.

Stars brighter than V=6.5 could not be observed without using a neutral-density filter. If the density filter was inserted the limit was V=4.0.

A photometric data acquisition system similar to that of the Danish 0.5-metre telescope was available to this photometer. With the help of the integrating TV system, stars at least down to V=15.5 could be seen and centred in the diaphragm.

The Six-Channel uvby-H_β Photometer was decommissioned in the 1990s.