Precision SD Monitoring with the MS-95S

Quick Read Whitepaper Preview

What is Sunshine Duration?

The World Meterological Organization defines Sunshine Duration as The sum of the time for which the direct solar irradiance exceeds 120W/m². In climate research, meteorology and reporting, sunshine duration quantities are valuable to monitor seasonal variations between different locations, and are a useful indicator for a variety of applications, such as calculating solar energy potential, assessing crop growth conditions, or predicting weather patterns.

Many solutions exist to measure sunshine duration, but until now, have all come with their own set of challenges or drawbacks. This is why EKO Instruments developed the MS-95S. Keep reading and download the full Quick-Read Whitepaper at the bottom of this page to see how this new-concept sunshine duration sensor is revolutionizing sunshine duration monitoring for researchers, academics, and industry professionals around the world.

History of Development

Sunshine Duration Sensors

Throughout history, several types of sunshine recording devices have been developed and used, from photoelectric sunshine recorders, reference pyrheliometers, to rotating mirror recorders, etc.

Each has had its own critical limitations such as cost, maintenance requirements, or accuracy during days with sporadic cloud coverage, which prevent it from being an indisputable all-encompassing solution.

Enter the MS-95S

A New-Concept SD Sensor

To combat these limitations, EKO has developed the MS-95S Sunshine Duration Sensor with a revolutionary new design and measurement principle.

By combining an ultra-wide-angle lens and a quadrant silicon photodiode array sensor, the MS-95S is able to achieve unprecedented accuracy while maintaining a compact, low-cost and easy-to-install form factor with no moving parts or complex on-site adjustment required.

Precision Sunshine Duration

Sunshine duration sensors are put to the test when the sky fluctuates between sunny and cloudy conditions, since the received direct normal irradiance teeters close to the 120W/㎡ threshold.

To validate the unique measurement principle of the MS-95S, we conducted extenstive testing, putting it against the MS-093 SD Sensor and reference pyrheliometer. 

Compared with the MS-57 (reference pyrheliometer), seasonal variations of EKO’s MS-093 and MS-95S were 5% or less. However, the top competing sunshine duration sensor has large errors in monthly sunshine duration measurement data (more than 16%) and large seasonal variation.


MS-95S SD Sensor

  • Full Hemisphere Ultra-Wide Angle Lens Design for All-Sky Observation

  • Unmatched Stability, No recalibration required

  • Smart 4-channel Analog & Digital Interface

  • Internal Diagnostics for temperature, tilt, & roll

  • 2-year Standard Warranty

MS-95S SD Sensor


The MS-95S reinvents sunshine duration sensors, setting new standards for accuracy and stability. Low-cost, compact, light, and robust, the MS-95S does not require calibration and, paired with the MV-01 Ventilator & Heater, performs consistently in all weather conditions.

With an optical sensor design built around a new ultra-wide-angle lens that observes the sky in 180°, the MS-95S employs a unique method to distinguish and record direct beam radiation from total sky radiation. Unaffected by detector temperature effects, irradiance conditions, solar elevation angle or detector non-linearity, the MS-95S is the ultimate choice for maintenance-free, long-term operation.

Keep Reading

Register to download the complete 'Quick Read Whitepaper' and learn more about the MS-95S, how we validated its performance and how it is revolutionizing sunshine duration monitoring for researchers, academics, and industry professionals around the world.

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