Parts of Polaris Trail Telescope. This telescope was used to test the 'seeing' on potential locations. It does this by allowing the observer to study the trail left by the Pole star, Polaris, as the Earth turns. This trail can then be studied in order to determine the steadiness of the Earth's atmosphere

The second half of the 20th century saw a decline in national observatories as astronomers instead collaborated with their colleagues overseas to build bigger, more powerful and more expensive telescopes in high locations (on top of mountains) under clear skies where the seeing was good.
Seeing is a term used by astronomers to describe the clearness of their view of the stars. This telescope was used to test the 'seeing' on potential locations.

This telescope was used to test the seeing in Australia, when sites were being chosen for the Anglo-Australian Telescope (ATT).

It was also used at La Palma in the 1980s to determine whether or not El Roque de Los Muchachos would be a good place to build the Isaac Newton Group (ING) of telescopes.