In the constellation of Canes Venatici (the Hunting Dogs) lies the Sc galaxy, M51 (NGC5194). This was the galaxy that Lord Rosse sketched with his 72 inch reflector (the Leviathan) in 1845 and which showed the spiral nature of galaxies for the first time.

The above picture was taken on the 5th March 2009 using my friend's Celestron NextStar 102 SLT with a Fujifilm S2 digital SLR camera mounted at prime focus. The picture is a combination of 10 x 30 second exposures at ISO 800. North is in the direction of the top left-hand corner of the image. Although the location was a dark site near Malton in North Yorkshire, a first quarter Moon was setting in the west.

The 10 exposures were begun at 22:37 GMT and ended at 22:49. Dark frames were taken at a later date using the same camera set up - to mimic the cold temperatures on the night (frost was forming on the telescope) the camera was cooled in the fridge! The average dark frame was subtracted from the galaxy frames and the results added together in Photoshop. Note that there was 0.85 degrees of rotation between the last and first galaxy frames and this had to be taken into account. The results were processed using levels in Photoshop.

An enlarged image of M51 shows the structure of its blue spiral arms and its central yellow nucleus. Also, to the right is the companion galaxy NGC5195, to which M51 seems to be joined by a spiral arm. Deeper images show that the two galaxies have interacted in the past causing both systems to be distorted.