The two Gemini Multi-Object Spectrographs (GMOS), one on each telescope, provide 0.36-0.94 µm long-slit and multi-slit spectroscopy and imaging over a 5.5 square arcminute field of view. Each GMOS is also equipped with an Integral Field Unit (IFU) making it possible to obtain spectra from a 35 square arcsecond area with a sampling of 0.2 arcseconds. The Nod-and-Shuffle mode, which enables superior sky subtraction, is available with both GMOS-N and GMOS-S in most spectroscopic modes.

The GMOS were built by a collaboration of the Astronomy Technology Centre at the ROE, the University of Durham in the UK and the Herzberg Institute of Astrophysics in Canada. GMOS-N was delivered in July 2001 with GMOS-S following in December 2002.

The Instrument Scientists for GMOS are German Gimeno (GMOS-S) and Julia Scharwächter (GMOS-N).

Gemini staff who also support GMOS-N include Kristin Chiboucas and Jason Chu. The GMOS-N team can be contacted at gmos_n_science 'at' gemini.edu.

 Announcements

New Red-Sensitive CCDs manufactured by Hamamatsu Photonics were installed at GMOS-S in June 2014; more information regarding these CCDs is available on the GMOS-S Array (Hamamatsu) webpages. The GMOS-N e2v deep depletion devices were replaced by Hamamatsu CCDs in February 2017. See the Status and Availability webpage for more details on the Hamamatsu project.

In order to allow observers to take advantage of the wavelength regime opened up by the new detectors, we have installed two new filters (Z and Y) for imaging and band limited spectroscopy in the far red at both GMOS. These new filters are available now. See the GMOS filters webpage for more details.

See the Status and Availability page for current instrument configurations.

GMOS Science Highlights

How to Use These Pages

The GMOS pages are organized as follows:

• Status and Availability: Modes available in the current and upcoming semesters; current grating and slit configurations.
• Nod-and-Shuffle: All you ever wanted to know about this remarkable GMOS capability - including when and how to use it.
• Imaging: GMOS is not just a MOS, or an S; it is a camera too; info on camera properties, filters and detectors.
• Spectroscopy Overview: Introduction and properties of gratings, blocking filters, and detectors.
• Long-slit Spectroscopy
• Multi-object Spectroscopy (including mask-making)
• Integral Field Spectroscopy
• ITC, Sensitivity and Overheads: Sensitivity tables, integration time calculator, and details of observing overheads.
• Guiding Options: The GMOS OIWFS and how to use it; when to use the peripheral wavefront sensors with GMOS.
• Calibration: Info on GCAL, flats and arcs, standard stars, and baseline calibrations.
• Observation Preparation: How to configure GMOS in the Observing Tool; observing strategies and checklists.
• Data Format and Reduction: Examples of GMOS data and links to data reduction resources.
• Documents: GMOS optical layout; design documents and references.