The Palomar Transient Factory (PTF) discovered a supernova in M101 on August 24th. At magnitude 17.2 it was pretty faint, but as this supernova was discovered ‘on the rise’ it has been steadily brightening, and may reach mag. 10 or 11 – making it easily visible in binoculars or a small telescope.

Image of supernova PTF11kly in M101 by BAA Member Denis Buczyski

Although M101 is in the circumpolar constellation of Ursa Major, and so will never set from UK locations, it does not attain a very high altitude, and will be best placed for observation as soon as the sky becomes dark.

The observations of supernovae are important, because they are a key component of the distance ladder. This is a series of stepping stone techniques used to measure distances to far-off galaxies. It is thought that type Ia supernovae explode with much the same brightness due to the physical nature of the star, so finding a supernova relatively close-by helps our understanding of the physics of the explosion, and further help the calibration of the distance scale.

Amateur astronomers can best contribute to the science by measuring the brightness of the supernova, and contribute to it’s light curve.

But there is also a great pleasure in seeing for yourself one of the greatest cosmic events, which happened 23 million years ago and the light of the event has just reached us.