M10 Globular cluster in Ophiuchus

A cropped view of M10 situated some 14,300 light years away.

 Discovered on the 29th May 1764 by Charles Messier,this faint cluster (magnitude 6.6) cannot be seen by the naked eye even though its 83 million light years in diameter.
Travelling away from us at 69 kilometres per second it it lies only 16,000 light years from the centre of the our galaxy the Milky Way.

Full size image

Taken using 7 x 180 second exposures at iso800 & Canon 40D.
Sky-watcher ED80 DS pro refractor with 0.85 reducer.field flattener.
Focused using a Bahtinov mask
Heq5 pro mount guided by a Sky-watcher 80T refractor , ZWOASI120MC camera and PHD2.
Processed in Deep Sky Stacker and Photoshop CC.

This is the first time I have used the ED80 focal reducer/field flattener which improves the focal ration from f/7.5 to f/6.375. The field flattening is now very good with virtually no signs of coma (smudged stars away from the centre of the image). Nice round stars, even in the corners of the image!!!