And the rotation has to be both continuous and at a constant speed, which for the LZT is 8.5 revolutions per minute.

FORBES: Liquid Mirror Telescope Technology Finally Going Mainstream

To date, the LZT is largest, although India, Belgium and Canada are building the International Liquid Mirror Telescope (ILMT), a 4-meter project which should see completion by March.

FORBES: Liquid Mirror Telescope Technology Finally Going Mainstream

The largest, the 6-meter Large Zenith Telescope (LZT) operated by the University of British Columbia in Vancouver, stands on a hilltop in a research forest some 40 miles east of the city.

FORBES: Liquid Mirror Telescope Technology Finally Going Mainstream