What is the name of the bright star that changes colour when it twinkles, from blue to red to bluey green?

Question

It lies northish in the sky, but quite low. Also I'm in the southern hemisphere so you might see it in the southern sky

Answer 1

Any bright star within 15 degrees of the horizon might do that. I watched one of them a few nights ago through my 8x40 monocular: red, blue, green, red...

Answer 2

Stars twinkle because their light falls on one rod or cone cell at a time on your retina. Bright blue stars change color because they appear red when the light falls on a red cone cell, blue when it falls on a blue cone cell and green when it falls on a green cone cell. Bright orange or yellow stars don't change colors because they don't stimulate blue cone cells. Dimmer stars are not bright enough to stimulate cone cells; they appear gray because they only stimulate rod cells.

The brightest star, Sirius, is a blue star, so it is famous for changing colors.  

Answer 3

Any very bright star can twinkle like this but the brighter it is the more likely it is to twinkle when low on the horizon. Sirius is the brightest star and is famous for flashing in different colours.

Answer 4

use the software stellarium to track any thing which is in the sky.  

Answer 5

Probably the star you are seeing is Vega, in the constellation Lyra. It is on the meridian around 9 p.m. at present, and is pretty low in the sky, 17°  altitude from Sydney, for example. We northerners get similar "light shows" from Sirius in our winter sky. If you look at this star with binoculars, you should see two bright stars to its right forming an equilateral triangle. The lower right star will appear as a double star in binoculars, Epsilon Lyrae.