What is Interferometry?

Interferometry is a technique used by scientists and engineers. Tools called interferometers add together 2 or more waves of light. When they do this, the waves of light interact (or interfere) with each other. This can add the waves together, making them brighter. It can also cancel the waves out. Interference only takes place if the waves come from the same object or have the same frequency. We call these types of wave coherent.

Gemini North Telescope

The Gemini project is a multi-national partnership of seven countries that has resulted in two identical 8.1 metre telescopes - one on Hawaii's Mauna Kea mountain (Gemini North) and the other on central Chile's Cerro Pachon mountain (Gemini South). As well as the United Kingdom, the others partners in the project are the United States, Canada, Chile, Australia, Brazil and Argentina.

GranTeCan Telescope

The Gran Telescopio Canarias, also known as GranTeCan or GTC, is a 10.4 metre telescope, which began operations in 2009. The GTC Project is a partnership between Spain, Mexico, the University of Florida and the Instituto de Astrofísica de Canarias (IAC).

Anglo-Australian Telescope

Commissioned way back in 1974, the Anglo-Australian Telescope was one of the last 4 metre equatorially mounted telescopes to be constructed. Such telescopes are tilted to align with the rotation of the Earth, and follow or track a star through the sky they only have to move in one direction. Most modern large telescopes have to move in two directions to follow a star - a more complicated technique but possible these days with the advent of modern computers.

Astronomical Seeing

Variations in Seeing on Star and Moon
Credit: NSO

Astronomical seeing is why objects in the night sky appear to blur and twinkle. The worse the seeing, the more they blur. It is changes in the Earth's atmosphere. which causes the seeing conditions. The less steady the atmosphere, the worse the seeing becomes.