Silicon pyranometers are the best choice
I am excited that I just got to do my first post on Apogee's blog. You should read some of the posts.
I wrote about why our silicon-based pyranometers are better for use monitoring solar panel output than blackbody-type pyranometers. Price is one significant reason but more importantly is that the response of the silicon-cell pyranometer closely matches that of a solar panel since it too is silicon based.
Then there is also the ruggedness of our sensors versus other sensors. Our sensors are often permanently submerged in salt-water tanks to monitor light for growing coral. Our sensors withstand extreme cold and heat. We have bunches of them on the roof year round doing life-time tests. It will sometimes get as cold as -30 Celsius (-22 Fahrenheit) in the winter with snow, ice, etc. Then in the summer it can get as warm as 40 Celsius (104 Fahrenheit). To further test them, we have put a bunch of sensors in a temperature cycling unit with temperature swings from -20 Celsius (-4 Fahrenheit) to 90 Celsius (about 195 Fahrenheit) every three hours for about 8 months. They still work although we highly do not recommend getting the sensors that hot.
In the blog post, I mention briefly the photo-electric effect which is how a solar panel and a photodiode work. It was first written about by Einstein about 106 years ago. How amazing is that? I get to write something and reference Einstein for his work that is still pertanent to us today.
You can read the full post here.