OMC - Optical Monitoring Camera

The Optical Monitoring Camera (OMC) observes the optical emission of objects and dedicated to fine spectroscopy allowing to map the universe.

OIP, as a subcontractor to Centre Spatial de Liège (CSL, B), has designed and developed the OMC objective. OMC was successfully flown on the ESA scientific Integral mission.

Optical Monitoring Camera

The Optical Monitoring Camera (OMC) is a standard optical refractor enhanced with baffles and covers, that is part of the INTEGRAL (International Gamma-Ray Astrophysics Laboratory) Payload. The OMC observes the optical emission of objects and dedicated to fine spectroscopy.

The Optical Monitoring Camera consists of a passively cooled CCD (2055 x 1056 pixels, imaging area: 1024 x 1024 pixels) working in frame transfer mode. The CCD is located in the focal plane of a 50 mm (diameter) lens including a Johnson V-filter to cover the 500 – 600 nm (CCD: 850 nm) wavelength range. The OMC is mounted close to the top of the INTEGRAL payload module structure.

The OMC consists of 3 sub-systems:

  1. the optical system (based on a 6-lens objective mounted in a titanium alloy barrel)
  2. the baffle (consist in a 600mm length aluminium alloy cylinder surrounding the optical system and including internal vanes to provide the necessary straylight reduction)
  3. the cover system (consists of a door mechanism and a forebaffle. The door is closed on ground and during launch to prevent the optics from contamination. The mechanism was operated only once in flight).

The OMC observes the optical emission from the prime targets of the Integral main gamma-ray instruments with the support of the X-Ray Monitor JEM-X. The OMC offered the first opportunity to make long observations in the optical band simultaneously with those at X-rays and gamma-rays. This capability provided invaluable diagnostic information on the nature and the physics of the sources over a broad wavelength range. Multi-wavelength observations are particularly important in high-energy astrophysics where variability is typically rapid. The wide band observing opportunity offered by Integral is of unique importance in providing for the first time simultaneous observations over seven orders of magnitude in photon energy for some of the most energetic objects in the Universe, Supernova explosions, active binary systems, black hole candidates, high energy transients, serendipitous sources and gamma-ray bursts.



  • Wavelength range: 500 – 600nm (by Johnson V-filter)
  • Detector: 50 mm lens + CCD (2055 x 1056 pixels), imaging area = 1024 x 1024 pixels
  • Pixel size: 13 x 13µm
  • Field of view: 4.979° x 4.979°
  • Aperture: 5cm diameter
  • Focal length: 153.7mm (f/3.1)
  • CCD Quantum Efficiency: 88% at 550nm
  • CCD full well capacity: ~120 000 electrons/pixel
  • Angular resolution: 23″ Gauss PSF
  • Typical integration times: 10 s – 50 s – 200 s
  • Sensitivity (3 sigma in 10 x 200 s): 18.1 mag (v)



Solution: Camera

Type: High Resolution

Application field: Science – Stars – Mapping the universe

Mission: Integral (ESA)

Life: Operational (launch 2002)


The ESA scientific mission INTEGRAL (The INTErnational Gamma-Ray Astrophysics Laboratory) is dedicated to the fine spectroscopy and fine imaging of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent monitoring in the X-ray (3-35 keV) and optical (V-band) energy range.

  • INTEGRAL is an ESA mission in cooperation with Russia and the United States.
  • INTEGRAL is detecting some of the most energetic radiation that comes from space. It is the most sensitive gamma-ray observatory ever launched.
  • INTEGRAL is providing new insight into the most violent and exotic objects of the Universe, such as black holes, neutron stars, active galactic nuclei and supernovae.
  • INTEGRAL is also helping us to understand processes such as the formation of new chemical elements and mysterious gamma-ray bursts, the most energetic phenomena in the Universe.
  • INTEGRAL also has an optical camera and X-ray detector, energy range 3 to 35 keV, for simultaneous observations across the electro-magnetic spectrum.

INTEGRAL was successfully launched with a Russian PROTON launcher on 17 October 2002 from the Baikonur Cosmodrome, Kazachstan.

OIP’s Participation

OIP, as a subcontractor to Centre Spatial de Liège (CSL, Liège, Belgium), was involved in the design, development, manufacture and test of (1) the OMC cover, (2) the OMC baffle, (3) the OMC Optical System and (4) the overall OMC system during phase C/D.

CSL was responsible for the optical and straylight cancellation design, the lens barrel, the baffle manufacturing, the door mechanism and environmental tests. The participation of the Liège University and of the Centre Spatial is supported through a PRODEX contract with the Belgian Science Policy Office.


All subsystems were delivered in time to CSL (B), under a very stringent (aggressive) schedule. The OMC instrument was assembled and tested at CSL.

The instrument was successfully flown and is still fully operational (after several mission extensions). The mission end is scheduled for December 31st, 2018, a decision which is subject to a mid-term review in 2016).


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