Friday, 7 August 2009

M19, the elongated globular cluster

Just a quick post to keep the blog ticking over. M19... A curiously elongated globular. One of my sharper images on the 20", but still a but fuzzy. I had to play around with the colour, as Deep Sky Stacker decided to give the midtones a green tinge when it stacked the pics. If I remember right, this was about 10 x 15 second shots on the 20", when it was tracking well, with darks and a flat. As far as globulars go this one is very close to and slightly further away than the centre of the galaxy, and we're looking at it through a plethora of distant stars and a bit of dust. It's an impressively big and bright cluster and it can be seen in binoculars at magnitude 6.8 in the constellation Ophiuchus. But why is it elongated? My instinct tells me it's tidal forces from the centre of the galaxy, but that's pure speculation.

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