BEARS is a 5x5 channels SIS heterodyne receiver array for the Nobeyama 45 m telescope. BEARS was installed at the Nobeyama 45 m telescope in 1998. Details about BEARS are described in Sunada et al. (2000, SPIE 4015, 237) and Yamaguchi et al. (2000, SPIE 4015, 614).
| Number of beams | 5 x 5 (25 beams) |
|---|---|
| Beam separation | 41.1" grid spacing |
| Frequency range | 82 - 116GHz |
| IF frequency | 2.0 - 2.6 GHz (600MHz band width) |
| Operation | DSB mode |
Autocorrelators (MAC) can be used for observations with BEARS. You can select one of five modes. Details about MAC are described in Sorai et al. (2000, SPIE 4015, 86).
| Spectrometer | Band width | Ch | Resolution* |
|---|---|---|---|
| AutoCorrelators | 512 MHz | 1024 | 500 kHz |
| AutoCorrelators | 32 MHz | 1024 | 31.25 kHz |
| AutoCorrelators | 16 MHz | 1024 | 15.63 kHz |
| AutoCorrelators | 8 MHz | 1024 | 7.81 kHz |
| AutoCorrelators | 4 MHz | 1024 | 3.91 kHz |
* Resolution depends on the window function of FFT, which you can select when you make the observation table. Frequency resolution of Autocorrelator depends on both the band width and the window function you selected. You can select from four window functions- none(x1.21), hanning(x2.00), hamming(x1.82), and brackman(x2.30). Frequency resolution are calculated by the next equation;
Frequency resolution = Bandwidth / 1024 x factor(window function).
For example, in the case of the 32 MHz bandwidth and the window function "none", the resulting resolution is 37.8 kHz.
You can use three observing modes; position switching, frequency switching and on-the-fly.