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what's up for june hello and welcome i'm

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jane houston jones at nasa's jet

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propulsion laboratory in pasadena

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california 2009 is international year of

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astronomy and each month this year we're

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showcasing a great celestial object

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this month it's the hercules globular

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cluster which is also called m13

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it's called m13 because this object is

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the 13th of charles messier's 1764

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catalog of celestial objects but charles

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messier wasn't the discoverer of this

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cluster

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m13 was discovered half a century

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earlier by edmund halley

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a globular cluster is a collection of

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hundreds of thousands of ancient stars

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held together by gravity

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you can easily find m13 in the keystone

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of the constellation hercules about a

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third of the way along a line drawn

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between ada and zeta herculis

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m13 will look like a round hazy glow in

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binoculars through a telescope you'll

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see individual stars at the edge of the

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cluster and a dense core of stars closer

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to the center

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the hubble space telescope's wide field

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and planetary camera 2 or with pic 2 for

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short and the advanced camera for

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surveys combined data from 1999 through

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2006 to create a glittering image of

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this herculean star city

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a spiral galaxy like our milky way is

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made up of three visible parts the

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nucleus the disc and the halo

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the nucleus contains the highest density

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of stars in the galaxy

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most of the gas and dust is contained in

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the disk

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the halo or outer shell is spherical and

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contains little gas dust or star

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formation

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the globular clusters found in the halo

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are the oldest parts of the galaxy

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m13 is one of 150 globular clusters in

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this is the last month to get a good

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look at saturn in the evening sky so

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don't miss it

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the rings are narrowing to nearly edge

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on and look dimmer than they did last

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month

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you can read about the hercules globular

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cluster on nasa's international year of

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and you can learn all about nasa's