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The MPIfR Bolometer array

The 19-channel MPIfR bolometer array which was installed at the telescope in February 1996 will be again available this winter. The horns are located at the center and on the sides of two concentric hexagons with beam spacings tex2html_wrap_inline928 . Each channel has a sensitivity of tex2html_wrap_inline930 mJy s tex2html_wrap_inline789 under good weather conditions and a HPBW of 11''.

The bolometer will normally be operated by wobbling at 2 Hz the secondary mirror in azimuth. As the array if fixed in Nasmyth coordinates, the orientation of the 19 beams with respect to the sky and to the chopping direction changes with elevation. Special software is made available at the telescope for data reduction (NIC [11] and MOPS [12]). Last winter, due to alignment problems and poorly understood interferences, it turned out difficult to reliably detect and map sources with fluxes of less than 2-3 mJy per beam. The reasons for this are currently under study at MPIfR. Observers should be aware of these limitations and carefully plan their observations of weak sources (please contact IRAM for more informations).