Australian and New Zealand amateur and community astronomers with telescopes are being encouraged to join a new project being run by the NASA New Horizons mission team, in determining one of astronomy’s distance parameters – the measurement of parallax.
On April 22nd and 23rd, astronomers around the world are being asked to point their telescopes and digital cameras towards two nearby stars – Proxima Centauri (currently the closest to our Solar System) and Wolf 359 and photograph the stars.
At the same time, the New Horizons spacecraft, which is nearing a distance of 8 billion kilometres from Earth will also take images of the two stars. When combined with Earth-based images captured by amateurs and community astronomers, the images will produce a record-setting parallax measurement that will look 3D with the stars popping out from the background.
Parallax is an old astronomical technique, utilised for roughly two centuries, and used to determine the distance for relatively nearby stars. Traditionally, stellar parallax works by recording the position of a nearby star, against fixed background stars which are much further away. Then, as the Earth orbits the Sun – six months later, taking a new recording of that nearby star to note how much it has shifted its position relative to the background fixed stars. By knowing the distance between the two observational points in Earth’s orbit, and accounting for the apparent shift in angle, astronomers use this value to determine the distance to stars.