Larry Klaes posted the below. Do you remember Comet Halley?
- LRK -

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Giotto’s brief encounter
http://www.esa.int/esaCP/SEMSZ0NVGJE_index_0.html
Twenty years ago, in the night between 13 and 14 March 1986, ESA’s Giotto spacecraft encountered Comet Halley.
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It came by in 1910 when my mom was born and she wanted to live to see it again. (95 now)

It comes by every 76 years or so and this time it wasn't the best view as it went by the Sun on the far side from us in 1986.
http://www.seds.org/nineplanets/nineplanets/halley.html

Where will you be in 2062 when it comes by again? :-)

O.K., what were you doing when it came by in 1986?

I was supporting the Pioneer missions at NASA Ames and we had Pioneer-Venus (Pioneer 12) going around Venus and it had just gone by the Sun on the far side from Earth. The project turned Pioneer-Venus so that it could view Comet Halley and gather information on its glow in the ultraviolet.
- LRK -

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Small image
http://t2www.nasa.r3h.net/centers/ames/images/content/118550main_AC86-0107-5-m.jpg
Large image
http://t2www.nasa.r3h.net/centers/ames/images/content/118532main_AC86-0107-5.jpg
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Well that was just one of many comets.
http://www.windows.ucar.edu/cgi-bin/tour_def/comets/comets.html

And now we have brought some of one back.
http://stardust.jpl.nasa.gov/home/index.html

Where do we go next? Ummm, if we don't cancel all the projects.

Thanks for looking up with me.

Larry Kellogg

Web Site: http://lkellogg.vttoth.com/LarryRussellKellogg/
BlogSpot: http://kelloggserialreports.blogspot.com/
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http://www.esa.int/esaCP/SEMSZ0NVGJE_index_0.html
Giotto’s brief encounter
10 March 2006

Twenty years ago, in the night between 13 and 14 March 1986, ESA’s Giotto spacecraft encountered Comet Halley. It was ESA’s first deep space mission, and part of an ambitious international effort to solve the riddles surrounding this mysterious object.

The adventure began when Giotto was launched by an Ariane 1 rocket (flight V14) on 2 July 1985. After three revolutions around the Earth, the on-board motor was fired to inject it into an interplanetary orbit.

After a cruise of eight months and almost 150 million kilometres, the spacecraft’s instruments first detected hydrogen ions from Halley at a distance of 7.8 million kilometres from the comet on 12 March 1986.

Giotto encountered Comet Halley about one day later, when it crossed the bow shock of the solar wind (the region where a shock wave is created as the supersonic solar particles slow to subsonic speed). When Giotto entered the densest part of the dusty coma, the camera began tracking the brightest object (the nucleus) in its field of view.
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http://www.seds.org/nineplanets/nineplanets/halley.html
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The average period of Halley's orbit is 76 years but you cannot calculate the dates of its reappearances by simply subtracting multiples of 76 years from 1986. The gravitational pull of the major planets alters the orbital period from revolution to revolution. Nongravitational effects (such as the reaction from gasses boiled off during its passage near the Sun) also play an important, but smaller, role in altering the orbit. Between the years 239 BC and 1986 AD the orbital period has varied from 76.0 years (in 1986) to 79.3 years (in 451 and 1066). The closest perihelion passage to the time of Jesus are 11 BC and 66 AD; neither event took place in Jesus' lifetime. Its most famous appearance was in 1066 when it was seen at the Battle of Hastings, an event commemorated in the Bayeux Tapestry.

Comet Halley was visible in 1910 and again in 1986. Its next perihelion passage will be in early 2062.
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http://www.nasa.gov/centers/ames/multimedia/images/2005/comets1.html
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Halley's Comet studied by Pioneer-Venus spacecraft: The next two images show Comet Halley in Lyman Alpha light from hydrogen ions. These images were created from data collected by the Ultra-Violet Spectrometer on the Pioneer Venus Orbiter spacecraft during the days of February 2-6, 1986. During the six days, the spacecraft was maintained in a fixed attitude while the comet moved past, and the instrument scanned across the coma.

During the six days, telemetry data was collected from Deep Space Network (DSN) stations in Spain, Australia and California. The data was processed to assemble the scans into false color images where the lightest colors indicate the strongest signal.

These images show the cloud of hydrogen ions, which surrounded the comet during February 2-6. These images are actually a composite because different parts of the cloud were scanned each day, and also because individual ions moved from the nucleus to the edge in about four days. At the time that these images were acquired, the hydrogen coma was the largest object in the Solar System with a radius of about 0.1 Astronomical Unit. In ultra-violet light, the comet was the second brightest object in the Solar System (exceeded only by the Sun).

These images show asymmetry caused by radiation pressure from the Sun. Hydrogen ions initially leave the nucleus in all directions but eventually are deflected by radiation pressure and move away from the Sun. The size of the Hydrogen coma indicates that water was being evaporated from the nucleus at a rate of about 40 tons per second.
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http://en.wikipedia.org/wiki/Comet_Halley
Comet Halley

From Wikipedia, the free encyclopedia

Comet Halley, officially designated 1P/Halley, more generally known as Halley's Comet after Edmond Halley, is a comet that can be seen every 75-76 years. It is the most famous of all periodic comets, even though in every century many comets appear brighter and more spectacular. Halley's comet last appeared in the inner Solar System in 1986, and will next appear in the summer of 2061.

The most standard pronunciation of "Halley" - and the pronunciation that the astronomer himself probably used - is [hæli] (IPA), to rhyme with "valley". The once-standard alternate pronunciation [heIli] (to rhyme with "Bailey") led to rock and roll singer Bill Haley naming his band Bill Haley and the Comets.
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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK
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