(bold added)
In astronomy there are plenty of these, I mean PLENTY!
Are you familiar with
AAVSO (American Association of Variable Star Observers)? Despite its name, it is thoroughly international, and has done an awful lot work of exactly the kind covered by your "non-observation".
In radio astronomy, there are several long-running programs to observe pulsars; the combined data is regularly used for papers on a wide range of topics.
"Old data", such as digitised plates, is regularly mined for all sorts of research, from improving the orbital elements of asteroids (especially PHAs), to finding and monitoring previously undiscovered variables, to proper motion studies.
And so on.