I have had a Campbell Stokes Type Sunshine Recorder since the end of April 2022. It is a beautiful instrument. I have to change the card after sunset each day. The results are shown in my Manual Records here.

Sunshine recorder

Sunshine Recorder Reflecting Image

The photo on the right shows the sky inverted in the glass sphere of the recorder. Nice!

For full details of the recorder and the Sunshine Record Cards are on PDFs by year updated from time to time.

Records for 2022 - Records for 2023

New Cards are Very Poor

I had to start using a new set of cards in June 2023. The sun is burning big holes in these cards, see the image below

Sunshine Recorder Cards Compared

As can be seen the holes in the 2023 cards are much bigger. This got me thinking.... The Sunshine Hours will appear top be more with the newer cards. So, using Matplotlib and Python, a couple of Scatter Plots and some Linear Regression later we finish with these plots.

Scatter Plot Good PaperScatter Plot Bad Paper

This shows that the plots are totally different, so the readings cannot be compared