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Visible and Infrared Survey Telescope for Astronomy

VISTA Exposure Time Calculator

VISTA characteristics

Detectors 16 Raytheon VIRGO
(HgCdTe on CdZnTe substrate,
2048x2048 pixels)
Scale 0.34 ''/pix
F.O.V. 1.5°×1° (1)
Data volume 210 Gb/night
Filter Set Z Y J H Ks NB1.18μm

(1) 6 pawprints covering a filled tile

VISTA Focal Plane
(click on the image for more details)


VISTA is a 4-m class wide-field survey telescope equipped with an IR camera and located at ESO's Cerro Paranal Observatory in Chile. It is one of the most capable IR imaging survey instruments in the world. The most commonly used pages are:

The IR camera for VISTA is composed of 16 Raytheon VIRGO 2048x2048 20 micron pixel array detectors, with a pixel scale of 0.34" (f/3.25) and a field of view per exposure of 0.59 square degrees. Each detector is divided into 16 channels of 128x2048 pixels. The detectors are spaced at 90% and 42.5% of the detector width (see diagram). Six exposures (known as pawprints) are required to survey a contiguous area (tile) of 1.5 square degrees.

VISTA has eight filter housings including the broadband set ZYJHKs and a narrow band filter at 1.185μm. There is one filter wheel position available to hold a further filter. The eighth filter housing is blanked for darks.

Although the nightly data volume is quite variable, the average is expected to be about 250 GB with peaks of more than 600 GB.

Filters and Sensitivity

The following table lists the main properties of the VISTA filter set. Magnitudes are quoted in Vega. For more information and the filter profiles go to the filters documentation in our technical section.




Z Y J H Ks 1.18μm
Central Wavelength (μm) 0.88 1.02 1.25 1.65 2.15 1.18
FWHM (μm) 0.12 0.10 0.18 0.30 0.30 0.01

Magnitude Limit (5σ in 60s)(1)

21.3 20.7 20.2 19.3 18.2 18.7
Sky Brightness (mag/sq arcsec) 18.2 17.2 16.0 14.1 13.0 16.3

(1) 0.8" seeing in 2" diameter aperture. Calculated using the VISTA Exposure Time Calculator


Data Processing

CASU will be responsible for the processing of all data obtained with VISTA. The data will be shipped to Cambridge on disks as Rice-compressed multiextension FITS files ie. one FITS container file for all 16 detectors.


The manual for the VIRCAM data reduction pipeline is available online together with a tarball of the distribution. The VIRCAM pipeline software is provided as a point of reference and information for users of VISTA data. However, this does not include support for individual site installation and maintanence, nor requests for enhancements. Comments on the software and associated documentation should be sent to casuhelp or virvam at