Taurus – A Wide Field Imaging Fabry-Perot Spectrometer

Extract

TAURUS, an imaging Fabry-Perot system, was developed as a collaborative project by the Royal Greenwich Observatory and Imperial College London and is capable of obtaining seeing-limited velocity field information over a 9 arcminute field on a 4 m telescope. At the detector (the IPCS) the image of the source is modified by the fringe pattern of the capacitatively stabilized servo-controlled Fabry-Perot. As the Fabry-Perot is scanned, this fringe pattern tracks radially across the field and each pixel of the detector maps out a spectral line profile within the bandpass of the “blocking” interference filter. At each F-P spacing a picture (Typically 256 × 256 pixels) is recorded on computer disk. 100 pictures make up a complete scan, covering for example 1,200 km sec⁻¹ free spectral range (this range in practice depends on the particular etalon). In this manner a 3 D data cube of the field is built up where (X, Y, Z) are typically (256 pixels, 256 pixels, 100 steps).