8° incidence
365 to 970nm 
7 wavelengths 
0.01% resolution
0.1% accuracy



CT-7:   high precision, handheld, reflectometer-scatterometer  365nm-970nm

CT-7 is an instrument dedicated to monitoring of the coating quality of the high grade optical surfaces like telescope mirror.

CT-7 measures the specular reflection and the scatter using seven wavelengths spanning from UV to near IR.

The incidence angle is set to 8° from normal which is close approximation of the work configuration of telescope mirrors and a practical minimum for such compact instrument.

CT-7 is delivered with factory calibration and a reference gauge. In addition, as CT-7 is in essence an optical caliper, it can be set to fit your laboratory standard and repeat the measurements at the remote location.

The current model reaches repeatability of 0.01% fully beneffiting from it's high precision optical head stability.

Measurements are performed in such manner that the risk of damaging the precious mirror surface is minimized. The measure starts after a countdown of a few seconds, allowing gently placement of the instrument on the mirror. A three point isostatic contact is provided by spherical white Teflon touching feet. Moreover, the small incidence angle of the measuring beams makes the result little sensitive to the measurement distance so that the instrument can stand on an optical tissue.

Configurations of the instrument and data retrieval are facilitated by PC application CT-7 Console.

   See CT7 Flyer

Measuring reflectivity of a telescope mirror.

CT-7 facts:

Optical scheme of CT-7

Protective tissue
Taking a measurement with a protective tissue.


Release: 2010,
Major revisions: 2012, 1015
Last revision: Feb, 2018

Reflectivity    0-100.00% 
Scatter         0-20.0%  ( TIS for lambertian surfaces)
7 LED sources 365-970nm:
8° incidence
Reflectivity 8° from normal in incidence plane (specular)
Scatter    14° from normal, perpendicular to incidence plane


Power Source:
– Rechargeable Li-ION
– Duration > 200 measurements
– Charge Time ~ 3 hours
External: USB 5V 500mA

Data Transfer and control:

USB 2.0

Temperature Range:

Operations -30°C to + 45°C
Storage -40°C to + 50°C
Temperature drift 0..30°C:
Scatter ±0.1% overall
Reflectance ±0.1% overall
Temperature Coefficient:
Scatter detectors <±0.001% per °C
Reflectance detector <±0.001% per °C

Non-Volatile Memory:

Storage capacity >2M measurements
Real Time Clock time stamp for measurements
Named  measurements (for easy filtering)

OLED 1.7" (high contrast, works in negative temperatures)

PC Software – Included-
Downloads data to PC for statistical analysis.
Export of data for further processing
Data Archive
Control and diagnostics of CT-7
Win 7,8,10