Hβ Photometer at the Danish 1.54-m
The Hβ Photometer was mounted on the instrument adaptor at the Cassegrain focus of the Danish 1.54-metre telescope in 1979. This two-channel photometer allowed simultaneous measurements of the Hβ line through a narrow (λHβN = 486.4 nm) and a wide filter (λHβW = 487 nm). By using a neutral-density filter it was also possible to measure bright standard stars fainter than V=4.0 (without the neutral-density filter) or V=1.0 (with the neutral-density filter).
Six diaphragms with different diameters (100, 30, 20, 10, 7 and 4 arcseconds) were available on a wheel that could be rotated by pushing a button on an auxiliary instrument control rack. The data output was saved on paper tape in ASCII.
The Hβ Photometer was decommissioned in the 1980s.
This table lists the global capabilities of the instrument.