Monocerotis light echo

V838 Monocerotis is a star in the constellation Monocerotis and the light echo, seen here, is caused by the initial outburst of light from the star reflecting off intervening interstellar dust. Pretty spectacular.

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Not A Polished Start

After its launch on the 24 April 1990 it soon became clear that all was not well with the Hubble telescope, as images sent back were a little on the blurry side. It turns out that the highly polished surface of the mirror was suffering from a problem known as spherical aberration, something which affects the sharpness of an image when light rays reflect off the mirror's edge. The flaw was only very small, but when dealing with such huge distances it meant that it was enough to warrant a mission to put it right.

After 11 months of training the crew was sent up in 1993 where they spent 5 days repairing the telescope - the rest as they say is history.