MMTF: The Maryland-Magellan Tunable Filter

This paper describes the Maryland-Magellan Tunable Filter (MMTF) on the Magellan-Baade 6.5-meter telescope. MMTF is based on a 150-mm clear aperture Fabry-Perot (FP) etalon that operates in low orders and provides transmission bandpass and central wavelength adjustable from ~5 to ~15 A and from ~5000 to over ~9200 A, respectively. It is installed in the Inamori Magellan Areal Camera and Spectrograph (IMACS) and delivers an image quality of ~0.5" over a field of view of 27’ in diameter (monochromatic over ~10’). This versatile and easy-to-operate instrument has been used over the past three years for a wide variety of projects. This paper first reviews the basic principles of FP tunable filters, then provides a detailed description of the hardware and software associated with MMTF and the techniques developed to observe with this instrument and reduce the data. The main lessons learned in the course of the commissioning and implementation of MMTF are highlighted next, before concluding with a brief outlook on the future of MMTF and of similar facilities which are soon coming on line.

💡 Research Summary

The Maryland‑Magellan Tunable Filter (MMTF) is a Fabry‑Perot (FP) based imaging spectrograph installed in the Inamori Magellan Areal Camera and Spectrograph (IMACS) on the 6.5‑meter Magellan‑Baade telescope. It employs a 150 mm clear‑aperture FP etalon operated in low orders, which allows the central wavelength to be tuned continuously from roughly 5000 Å to beyond 9200 Å while the instrumental bandpass can be set anywhere between about 5 Å and 15 Å. This combination of a wide spectral range and a narrow, adjustable bandpass makes MMTF a versatile tool for narrow‑band imaging of specific emission lines (e.g., Hα,