Sun Sky Lunar Multiband Photometer

Remote sensing instruments




Numerous applications take advantage of the aerosol charateristics and atmospheric optical properties provided by the CE318 photometer

  • Climate and climate change studies
  • Air quality monitoring and forecast
  • Near real time detection of volcanic ash plumes
  • SDS (Sand Dust Storm) monitoring and forecast
  • Calibration of satellite instruments
  • Validation of satellite aerosol products
  • Correction of satellite images
  • Calibration of Ocean Color satellite borne instruments

User's benefits

Precision and high reliability

  • Day and night measurements
  • Improved high angular resolution tracking
  • Most wide-spread and scientifically validated multiband photometer
  • Several standard and entirely automatic scenarios of measurements
  • High measurement stability on the long term, even in harsh climatic conditions

Proven robustness under any climate

  • More than 1000 instruments operating around the world
  • Continuous operating even under extreme climatic conditions
  • Reinforced protection against lightning
  • High robustness and resistance to corrosion (over 15 years)
  • Reduced maintenance

Flexibility of use

  • Suitable for long-term installation within observation networks as well as for field campaign measurement
  • Operates without any human attendance in a fully automated way with its own solar generator
  • Large number of communication media: PC link, mobile phone (GSM/GPRS), Satellite for isolated locations


MicroAmps® technology

The CE318 photometer takes advantage from the unique Cimel MicroAmps® technologies, that result in meeting several very demanding yet complementary specifications:

  • Minimize electrical power consumption
  • Use secure, highly redundant communications protocols
  • Maximize the versatility of printed circuit boards
  • Minimize the number of connectors

These Micro-Amps® technologies result in CE318 photometer exceptional performances widely proven under any sort of climate, in terms of operating reliability.

Optical sensor head

  • Includes two detectors in order to cover the entire spectrum from 340 nm to 1640 nm
  • 1 Optical channel for each detector
  • Narrow and precisely defined field of view (1.3°) for measurements of aureole very near from the sun
  • High precision single-band filters inserted in the optical paths
  • Motor-driven filter wheel for nine (possible up to twelve) single band filters
  • Second motor-driven filter wheel adds polarization filters (in three directions) for models with polarization
  • Silicon photodiode detector for the UV and visible spectrum, and InGaAs detector for IR.
  • Extremely sensitive, low-noise electronic conversion, operating in a large temperature range
  • A dual external collimator mounted on the head eliminates all stray lights

 High precision robot

Automated robot

  • Two high-resolution driven systems with an original backlash integral adjustment due to a Cimel custom technology
  • High sensitivity tracking system based on a four-quadrant detector

Control unit 

Accuracy enhancement

  • Drives the tracker with higher resolution and faster motions
  • Equipped with a built-in barometer to automatically register the local atmospheric pressure
  • Now connected to a pyranometer for additional measurement and transmission of the global solar radiation

Better convenience of use

  • The internal memory includes an SD card with virtually unlimited capacity (no risk of data loss).
  • Larger and backlit built-in display for better reading and navigation through enhanced menus in all lightning conditions
  • Built-in GPS for automatic data localization and time synchronization

All control, data acquisition, storage and communication functions are integrated within a single metallic and hermetic control box, of high robustness.



The instrument performs preprogrammed tasks,  according to various scenarios:

  • Direct solar measurements: sun tracking and triggering of a multi-band measurement triplet
  • Sky measurements: positioning according to a main plan or to almucantar and triggering of a measurement cycle at several angles
  • Nighttime lunar measurements (when moonillumination is higher than 50%): periodic lunar tracking and triggering of a multiband measurement triplet

Keyboard-display interface is available to the users for configuring the instrument and checking operation.


  • Measurement data are automatically stored by the control unit
  • Stored data may be transferred directly by several methods:

- Automatic real time transfer, through an RS-232 fixed line connection, to a local PC equipped with PhotoGetData software

-For operation on isolated sites, a DCP transmitter may be added (see Options) with plug & play connection to automatically send data via the Data Collection System through meteorological satellites like Meteosat / MSG (Europe), GOES (Americas), FengYun (China), INSAT (India), Himawari (Japan). The user must request time slots to the DCS satellite operator

-Manual collection, through a USB line connection (temporary connection only), with a laptop equipped with PhotoGetData software

-Automatic real time transfer by GPRS to a FTP site

Data acquisition

The photometer is supplied with the PhotoGetData software, that may be installed on a PC equipped with Windows (7 or 8) operatinf system.

It offers the following functions:

  • Automatic acquisition of raw data through RS-232
  • Manual acquisition of raw data through USB line
  • Automatic data display
  • Automatic conversion and storage as ASCII files
  • Set up of photometer parameters
  • Update of photometer firmware

Data processing

Data processing covers several steps:

  • Application of calibration parameters
  • Cloud screening and data quality check
  • Calculation of spectral Aerosol Optical Depths and sky radiance
  • Retrieval of physico-optical parameters of aerosols and atmosphere

Several algorithms have been developped by the scientific community for this process.

AERONET is recognised by the worldwide scientific community as the reference network for the production of aerosol and atmosphere physico-optical parameters. It operates an almost fully automated process that generates operational checks and quality-assured final products.

See AERONET site (www.aeronet.gsfc.nasa.gov) for more details.

CE318-T photometers that operate within AERONET may send data through any of the 4 above-mentionned methods.


For photometers that do not operate within AERONET, Cimel provides the DIAAMS software that may be run on a PC equipped with Windows (7 or 8) operating system.

DIAAMS offers the following features:

  • User friendly graphic interface
  • Fully automated operation (near real time) or manual mode
  • Cloud detection and data filtering
  • Retrieval of aerosol and atmosphere physico-optical parameters
  • Graphic display
  • Data export combination with Cimel LiDAR measurements to provide aerosol vertical profiles

This software is based on the retrieval software developped by the Grupode Física de la Atmósfera of the University of Granada.

The following data may be retrieved:

  • Daytime and nighttime (lunar) Aerosol Optical Depths (AODs) and water vapor content
  • Aerosol size distribution
  • Complex refractive index
  •  Percentage of spherical particles
  •  Volume concentration
  • Effective radius of particles
  • Spectral phase functions and  asymmetry parameters
  • Single Scattering Albedo

Technical features

Specifications Value
Measurement Irradiance precision  < 0.1%
Field of view (full)  1.3°
Smallest scattering angle (from the sun) for sky measurements
Spectral range 340 to 1640 nm standard (depending on sensor head model)
Long term drift of single band filters’ transmission rate  < 1%/year
Robot Number of axes and angular scanning  2 axes for whole sky angular scanning (0°-360°, 0°-180°)
Mechanical precision  0.003°
Solar tracking precision (automatic tracking)  0.01°
Power supply  Solar panel  < 2 Wp
Environmental conditions Temperature range  -30°C to 70°C
Humidity range  0 to 100% RH
General Total weight with tripod infrastructure 38 kg



Post processing and deployment

CE318 deployed in Tamanrasset (Algeria)

Deployment of CE318 photometers on a scientific observation base

CE318 deployed in polar environment

Models & Options

Head models

Several sensor head models are available, according to desired application:

Reference Description Characteristics Applications
 TS9  Standard model  340, 380, 440, 500, 675, 870, 937, 1020, 1640 nm  Standard
TP9  Polarized model  340, 380, 440, 500, 675, 870, 937, 1020, 1640 nm

Polarization in 3 directions

 Polarized & non polarized measurements
TU9 BRDF measurements 380, 440, 550, 675, 740, 870, 937, 1020, 1640 nm  Satellite calibration
TU12   BRDF measurements  415, 440, 490, 555, 675, 702, 740, 782, 870, 937, 1020, 1640 nm Satellite calibration
TV12 (SEAPRISM) Measurement of radiances emerging from the water surface 400, 412.5, 442.5, 490, 510, 560, 620, 665, 779, 865, 937, 1020 nm Ocean Color Program (Satellite validation)

Other options

Sales reference Description Characteristics Applications
Heated-robot Supply of a Robot with built-in heating system, instead of standard robot Recommended for very cold climates (prevents mechanical robot blockage due to icing) Cold & polar climates
Satellite-Kit T440-KIT-318 DCP Satellite transmission system Transmitter, GPS, antenna, solar generator, enclosure, 2 m mast, anchorage system Remote sites