A Brief Description:
ARIES (Temporarily unavailable): NOTE: ARIES and the AO system are undergoing upgrades and are temporarily unavailable until sometime in 2019.

ARIES is a NIR diffraction limited imager and spectrograph which is fed by the MMT's AO beam. The wavelength range is currently 1 - 2.5um but will eventually be upgraded to 1 - 5um. Several modes of the instrument give an R range of 3,000 to 60,000 and imaging FOVs ranging from 20.0" to 104.4". It is a PI instrument. Please contact Don McCarthy. For instructions on how to propose to use ARIES please see here.  ARIES is almost always scheduled for bright time observations.

The Fundamental Capabilities:
Imaging Modes

CameraPixel ScaleField of ViewDiffraction limitedLimiting K mag*








0.1"/pix100"almost M22

* Limiting K magnitudes are estimated for sky-subtracted 10-sigma detections in 1 hour of total integration time in good conditions with 0.1" FWHM PSF at K band
Spectroscopic Modes

SlitDisperserCameraResolving PowerBandsLimiting K mag


low res gratingf/5.6500 - 2000JHKLM18

90" x 0.2"

low res gratingf/5.63000JHKLM16.5

90" x 0.4"

low res gratingf/5.61500JHKLM16.5

1" x 0.2"

echelle gratingf/5.630,000JHKLM13

1" 0.1"

echelle gratingf/10.350,000JHKLM12

Please Note that the LM band capabilities are not available currently. A large format 1-5 um detector is expected to be available in the future.

Further Information:

The Arizona Infrared imager and Echelle Spectrograph is designed to exploit the low thermal background and high optical throughput offered by the MMT's f/15 adaptive secondary system. With first imaging light achieved in 2003 and first spectra in 2007, ARIES is currently offered as a PI instrument. With three IR arrays, ARIES provides diffraction-limited imaging in the JHK(LM) atmospheric windows and long-slit and echelle spectroscopy at resolving powers from 1,500 to 50,000 (200 to 5 km/s). ARIES can also supply global wavefront tip/tilt information to the adaptive system using cryogenic pick-off mirrors to access field stars over a 90 arcsec diameter field at wavelengths from 1-2 microns.

ARIES consists of two dewars which share a common mount and vacuum. The 'purple dewar' is generally referenced as the imaging half of ARIES and also provides the spectrometer foreoptics. The 'green dewar' is generally referenced as the spectrometer half of ARIES. There is some cross-functionality between the two dewars: the imager contains a filter wheel that can provide slitless objective grism capabilities, and the spectrometer in turn has a grating selection mirror that can reference a flat mirror for wider field imaging.

To a greater or lesser degree, both halves of ARIES can be operated independently and simultaneously. Spectra of the science target can be acquired with the 'green' spectrometer while the spilt light in the slit plane can be imaged using the 'purple' camera.

Be aware that if you are applying to observe transits or obtain other time sensitive measurements with ARIES, it is unlikely that the instrument will be mounted at any time other than bright time. Please check whether your dates coincide with a bright moon phase before applying for time.

For further information please see the ARIES wiki.