photoelectric observation in a sentence

1. The fragmentary light curve was obtained by Austrian astronomers from photoelectric observations in the early 1980s.
2. The first rotational light-curve for this asteroid was obtained from photoelectric observations made by U . S . astronomers Edward Bowell and Schelte Bus in the 1970s ( ), and gave a rotation period of hours with a brightness variation of 0.84 magnitude ( ).
3. Al  Naimiy, H . M . K, Fleyeh, H ., and Al-Razzaz, J . : New Photoelectric Observations and Light Curve Analysis of the Eclipsing Variable 44I Boo, Astrophysics and Space Sciences Journal, Vol . 151, pp . 135 147, 1989.
4. Photoelectric observations  however not from surfaces, as in Berlin, but rather in bulk insulators  were started by Pohl together with his assistant Bernhard Gudden in 1919 . ( The research work from this period was described in detail in ( first part ) . ) They discovered that diamond crystals become electrically conducting after irradiation with light.
5. It's difficult to find photoelectric observation in a sentence.