Figure: Around supernova 1987A, before and just after the event

Sometime during 23 February 1987 a supernova exploded in the Large Magellanic Cloud (LMC), a nearby galaxy. However, the LMC is about 170,000 light years distant, so the supernova exploded 170,000 years ago. It was discovered the following day and brightened rapidly to become the first supernova to be easily visible to the unaided eye for almost 400 years.

This photograph shows the field around the site of the supernova in great detail, both before the supernova exploded (right) and about 10 days afterwards, when it was still brightening. The image of the star that exploded to create the supernova (see arrow) is elongated. This does not necessarily indicate any peculiarity or a close companion, rather it is the effect of stars being by chance aligned along the line of sight. Several other examples can be seen in this picture and other, different, blended images are seen in the photograph of the same field taken two weeks after the supernova appeared (left). The pre-supernova plates were taken over about 90 minutes on the night of 1984 February 5, centred on the Tarantula nebula, and were used to make to make AAT 44, AAT 49 and the negative overlay in AAT 48a. The post-supernova plates (LHS image) were exposed for a total of about an hour on the night of 1987 March 8.

The difference in image quality ('seeing') between these pictures is an effect of the Earth's atmosphere which was much steadier when the plates used to make the pre-supernova picture were taken.

Credit for image and text: ©1989-2002: Anglo-Australian Observatory, photograph by David Malin.

http://www.aao.gov.au/images/captions/aat050.html

Full resolution image: http://www.aao.gov.au/images/624x832_caption/aat050_72c.jpg