The Multi-Aperture Spectroscopic Telescope (MAST)
The Multi-Aperture Spectroscopic Telescope (MAST) is a novel system that is being developed for the Weizmann Astrophysical Observatory. Its main purpose will be the spectroscopic classification and follow-up of targets discovered by LAST and ULTRASAT using the broad-band, high-throughput DeepSpec spectrograph. In addition, MAST will be equipped with a high-resolution spectrograph, called HighSpec, for various galactic science cases.
DeepSpec covers a spectral range of 350 to 850 nm and will have a resolution of ~500. In a 5-minute exposure the system can reach a limiting magnitude of 19, while it is 20.5 for a 30min exposure.
HighSpec, on the other hand, provides high-resolution spectra of certain emission lines (Ca-II, Mg b and H-alpha) and can be used to measure radial velocities. It will be used for the study of galactic sources such as binary white dwarfs, flaring M stars, to search for star-black hole binaries.
The MAST array will consist of 20 prime-focus 60-cm telescopes which will have a collecting power equivalent to a single 2.7m telescope. MAST will be located next to LAST in similar enclosures. The base has already been constructed.
The telescopes will each be equipped with a guiding camera and fiber feed, developed by our group, that allows to couple light from a source into a 25-micron, few-mode optical fiber with a measured transmission of 90% for an F/3 beam. The plate scale of the MAST telescopes is 0.1 arcsec/micron which means that each fiber has a sky coverage of 2.5 arcsec. The median seeing at the site, tested over a year, is 1.3 arcsec. While this implies that we do not take full advantage of the seeing conditions in Neot Smadar, the selected fiber core gives us some margin for guiding errors.
All fibers will lead to a long-slit unit that can be plugged into one of two planned spectrographs and the traces of all telescopes can later be combined to increase the sensitivity to faint sources. Currently, we are designing two complementary instruments: DeepSpec is a broad-band, high-throughput instrument, and HighSpec will have a high resolution of R~22000 in three 10nm bands.