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what's up for may

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hello and welcome i'm jane houston jones

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at nasa's jet propulsion laboratory in

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pasadena california 2009 is

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international year of astronomy each

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month this year we'll take you on a tour

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of one of the best celestial objects on

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view

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this month it's our star the sun

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galileo and englishman thomas harriet

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both observed the sun and sunspots in

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1610 but they weren't the first

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chinese and korean astronomers wrote

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about sunspots almost 3000 years ago

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john of wurster who was an english monk

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made the earliest existing drawings of

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sunspots in 1128.

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galileo solar observations of 1612 were

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made at the same time of the day every

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day and so the motion of the spots

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across the sun can easily be seen

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this motion allowed early astronomers to

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estimate the sun's rotation period which

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is about 27 days

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the early astronomers soon projected the

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sun's image through the telescope onto a

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piece of paper or through a pinhole

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projector

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this made it possible to study the sun

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in detail without damaging their eyes

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many other astronomers in the 17th

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century including shiner gascendy and

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hevelius also recorded their solar

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observations

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more than two dozen past and present

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nasa missions explore the sun earth

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system

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the ulysses spacecraft which launched in

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1990 studied the sun before during and

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after the last solar maximum in 2001

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after more than 18 years in flight

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ulysses returned a wealth of data that

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led to a much broader understanding of

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the global structure of the sun's

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environment

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the trace spacecraft launched in 1998

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and it studies the magnetic structures

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which emerge through the photosphere or

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the visible surface of the sun

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the genesis spacecraft collected samples

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of the solar wind a stream of charged

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particles from the sun the samples were

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returned to earth in 2004 and are now

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being studied in a special lab at nasa's

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johnson space center

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stereo which launched in 2006 uses two

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observatories one ahead of the earth in

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its orbit and one behind to study the

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structure and evolution of solar storms

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as they blast from the sun and move out

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through space

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soho the solar and heliospheric

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observatory has been keeping a watch on

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the sun since 1996.

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it can warn the earth of approaching

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coronal mass ejections that could

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never look directly at the sun or you

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might damage your eyes

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contact your local amateur astronomy

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club and join them for safe solar

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observing

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and remember to view saturn this month

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the rings offer a different view

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they almost appear to be edge-on

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you can read all about the sun on nasa's

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international year of astronomy website

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and you can learn all about nasa's