(infrared observatory-satellite with 3.5-meter reflector)
Herschel Space Observatory (often just called Herschel) is a
3.5-meter Cassegrain reflector reflective infraredtelescope
in space at the L2 Lagrangian point.
It was launched by the European Space Agency
in 2009 and used until 2013 when it ran out of coolant.
The project was originally called
FIRST for Far Infrared and Submillimetre Telescope.
Instruments:
PACS "Photodetecting Array Camera and spectrometer"