This is the home page of the SPIRE photometer simulator (SPS). The SPS is a piece of software developed to simulate the operation of the Spectral and Photometric Imaging Receiver on-board the ESA’s Herschel Space Observatory.
SPIRE, the spectral and photometric imaging receiver, is one of three instruments on-board the European Space Agency's (ESA) Herschel space observatory. It contains a three-band submillimetre camera and an imaging Fourier transform spectrometer (FTS), and uses arrays of hexagonally packed feedhorn-coupled bolometric detectors operating at a temperature of 300 mK. The photometer has a field of view (FoV) of 4 x 8 arcminutes, observed simultaneously in spectral bands centred approximately at 250, 350 and 500 μm. The angular resolution is determined by the telescope diffraction limit, with full-width-half-maximum (FWHM) beam widths of approximately 18, 25 and 36 arcseconds at 250, 350 and 500 μm respectively. Maximising the aperture efficiency of the feedhorns requires an aperture corresponding to an angle of 2λ/D on the sky, where λ is the wavelength and D is the telescope diameter. Consequently, the detector beams have an angular separation of approximately twice the FWHM beam size on the sky.
The ultimate purpose of the SPS is to produce simulated SPIRE photometer data (both science and housekeeping), derived from a realistic physical model of the instrument. This model can be used to “observe” a simulated astronomical sky, using any of the allowed photometer observing functions (POFs). The sensitivity results should be compatible with the photometer sensitivity model (SPIRE-QMW-NOT-000642) and the Herschel observation planning tool HSpot, but the SPS constitutes a much more sophisticated and versatile tool for evaluating the photometer performance. It should be noted however that since the telescope movement is not modelled in detail, the total observing time of a simulation must not considered to be accurate.