Bimetallic actinograph, M.O. Mark III, by Casella, 1955

Max Robitzsch

Bimetallic actinograph, M.O. Mark III, by Casella, 1955

This solar radiation measuring instrument was designed by M Robitzsch in Germany in about 1915. At first the instrument worked in the principle of two bimetallic rings placed one above the other. By the year 1929, the mechanical design had been changed to an arrangement of two horizontal bimetallic strips, placed side by side, and further developments took place.

The instrument now had a receiving surface, under the glass dome, constisting of two parallel rectangular white-coated strips of bimetal between which is placed a similar strip of bimetal coated black. At one end the three strips are connected to a common rod. While the other ends of the white strips are connected to the frame of the instrument, the other end of the black strip is connected to a simple lever mechanism and its movements are recorded on a chart placed on a normal clock drum.

These movements are proportional to the temperature difference between the strips, and thus radiation intensity.


Object Number:
glass and metal
actinograph and actinograph and
Meteorological Office, Berkshire

Cite this page


We encourage the use and reuse of our collection data.

Data in the title, made, maker and details fields are released under Creative Commons Zero

Descriptions and all other text content are licensed under a Creative Commons Attribution 4.0 licence

Using our data


Download catalogue entry as json

View manifest in IIIF viewer

Add to Animal Crossing Art Generator

Download manifest IIIF

Our records are constantly being enhanced and improved, but please note that we cannot guarantee the accuracy of any information shown on this website.