The Maryland-Magellan Tunable Filter (MMTF) is a tunable narrow-band filter that is used in the IMACS spectrograph on the Baade (Magellan I) 6.5m telescope at Las Campanas Observatory, Chile. The MMTF is based on a Fabry-Perot etalon with clear aperture of 150mm. It operates in low orders (close plate spacings) to provide a transmission bandpass which is adjustable from about 10 to 30 A, and a central wavelength tunable from about 5000 to 9200 A. When used with the IMACS short camera, the field of view of the imager is about 27 arcminutes diameter and the diameter of the central monochromatic part of the field will be about 7-11 arcminutes for bandwidths 10-30 A respectively. The MMTF operates on similar principles to the Taurus Tunable Filter. The MMTF is made possible by a collaboration between the University of Maryland, the Carnegie Observatories, and Magellan, and is made possible by an NSF ATI grant (NSF AST-0242860), PI: Sylvain Veilleux. Co-Is and collaborators include Alan Dressler (OCIW), Joss Bland-Hawthorn (AAO), Bruce Bigelow (OCIW/Michigan), Michael Rauch(OCIW), David Rupke (Maryland), Patrick Shopbell (Caltech), Brian Sutin (OCIW/Skewray), Ian Thompson (OCIW), Stuart Vogel (Maryland), Benjamin Weiner (Maryland/Arizona), and Ray Weymann (OCIW).
This web page is under construction, and provides updates on the MMTF status. Eventually it will have full operating specs, documentation, and software; right now we have the first light images from commissioning, and some more-reduced pretty pictures and results.
Further information for observers considering Magellan proposals in semester 2007B.
The MMTF Fabry-Perot calculator. This calculator will help you solve the Fabry-Perot equations that determine wavelength as a function of controller setting (MMTF-Z) and radius in the image.
MMTF setup guide (VERY RAW DRAFT), v0.2 of documentation for setup and observing procedures with the MMTF.
Guide to Step 1 of reducing MMTF data. This guide provides scripts for processing and flatfielding IMACS CCD mosaic data and walks you through using them. This is step 1 in that it gets you flat-fielded images, but the wavelength calibration must still be done manually. Note that the CCD processing is not MMTF-specific, so the scripts may also be used to reduce any IMACS 8k x 8k CCD mosaic imaging data, e.g. standard broadband filters.
The first MMTF commissioning run at Las Campanas was carried out during the Magellan Baade telescope's engineering run June 8-10 2006.
Sections of first and second light images from the MMTF, of H-alpha
emission from the local galaxies NGC 4945 and NGC 5128.
Click for larger versions.
A variety of tests of the MMTF wavelength behavior and stability were done, and we obtained narrow-band H-alpha images of the local galaxies NGC 4945 and NGC 5128 to exercise data reduction methods. We observed several emission-line standards to obtain flux calibrations. We have some initial commissioning pictures and results and more to come.
Delivery: The MMTF 150mm etalon has been successfully coated with a broad-band reflective coating. After some shipping misadventures, the MMTF etalon and CS-100 controller arrived at OCIW offices in Pasadena in November 2005. Staff at Santa Barbara Street connected the Palomar CS-100 and MMTF etalon and verified that both are operational, and that the IMACS instrument software can command the CS-100 controller through its serial interface.
Testing: On January 25 - February 1 2006, we carried out a series of tests of the MMTF spectral properties, computer interface, and operation. A report on the testing results has been written; a few pictures are below and more are to be added.
Some pictures from MMTF testing in the lab at OCIW.
Review: A pre-ship review of the MMTF took place at OCIW on March 23 2006. Documents for the review are available. The MMTF is ready for commissioning.
Commissioning: The first MMTF commissioning run at Las Campanas was carried out during the Magellan Baade telescope's engineering run June 8-10 2006.
First Light: First light images with the MMTF in the IMACS spectrograph on the Magellan Baade telescope from June 9-10, 2006.
The Maryland-Magellan Tunable Filter project is a collaboration between the University of Maryland and the Observatories of the Carnegie Institution of Washington. Construction of the MMTF is funded by a grant from the National Science Foundation, Advanced Techniques in Instrumentation program, NSF AST-0242860.
For questions and comments on the MMTF, the primary contact is the PI, Prof. Sylvain Veilleux, veilleux at astro.umd.edu. For specific questions about these webpages, contact Benjamin Weiner, bjw at astro.umd.edu (current address: bjw at as.arizona.edu).
Department of Astronomy, University of Maryland
(current address for BJW: Steward Observatory, University of Arizona)
bjw at astro.umd.edu/as.arizona.edu, updated August 2006.