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 Project Jupiter
II. Background

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Abstract
I. Purpose
II. Background
III. Orbits
IV. Period  Determination
V. Methods
VI. Kepler's Laws
VII. Observing Suggestions
VIII. Data Gathering
IX. Data Processing
X. Observer's Data Results
XI. Other Quad-A Results
XII. Conclusions
XIII. Attachments


This Project Jupiter Report was prepared by
Mizar Consulting
Eugene A. Lanning
130 Hillside Terrace
Nebraska City, NE
68410-3740
ealanni@alltel.net
Member of AAAA


AAAA
The American Association of Amateur Astronomers
P.O. Box 7981
Dallas, TX
75209-0981
e-Mail:
aaaa@astromax.com

www.AstroMax.com


Project Jupiter

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II. Background

A. Who first observed

Probably the most significant contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610, through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet (2) . The next evening, these stars seemed to have moved the wrong way, which caught his attention. Galileo continued to observe the stars and Jupiter for the next week. On January 11, a fourth star (which would later turn out to be Ganymede) appeared. After a week, Galileo had observed that the four stars never left the vicinity of Jupiter and appeared to be carried along with the planet, and that they changed their position with respect to each other and Jupiter. Finally, Galileo determined that what he was observing were not stars, but planetary bodies that were in orbit around Jupiter. This discovery provided evidence in support of the Copernican system and showed that everything did not revolve around the Earth.(3)

Galileo originally called the Jupiter's moons the "Medicean planets", after the Medici family and referred to the individual moons numerically as I, II, III and IV. Galileo's naming system would be used for a couple of centuries. It wouldn't be until the mid-1800's that the names of the Galilean moons, Io, Europa, Ganymede and Callisto, would be officially adopted, and only after it became very apparent that naming moons by number would be very confusing as new additional moons were being discovered. (4)

B. Number

Jupiter is typically listed as having twelve moons, although 27 have been discovered (5). Four of the moons are easily detected in most telescopes, and will be the moons observed in Project Jupiter. The next eight are of magnitude 13 through 19, needing a telescope of greater than 10 inches of aperture to detect the moons visually.

Detailed information about all of the moons of Jupiter is available at http://nssdc.gsfc.nasa.gov/planetary/factsheet/joviansatfact.html.


2 See Attachment E, taken from http://www.jpl.nasa.gov/galileo/ganymede/discovery.html, by Ron Baalke

3 Taken from http://www.jpl.nasa.gov/galileo/ganymede/discovery.html, by Ron Baalke

4 Source: http://www.jpl.nasa.gov/galileo/ganymede/discovery.html, by Ron Baalke.

5 Some sources report 39, perhaps a number that will yet increase. All of the newly discovered satellites are small and not observable by amateurs.

[Home]
[Abstract]
[I. Purpose]
[II. Background]
[III. Orbits]
[IV. Period  Determination]
[V. Methods]
[VI. Kepler's Laws]
[VII. Observing Suggestions]
[VIII. Data Gathering]
[IX. Data Processing]
[X. Observer's Data Results]
[XI. Other Quad-A Results]
[XII. Conclusions]
[XIII. Attachments]

 

The image of Jupiter on the Project Jupiter cover page is courtesy of AAAA member Charlie Warren of Texas. Used by permission. Jupiter and three of its moons - right to left are the moons Europa, Io and Ganymede. Callisto is not on the image. CCD Image taken February 2, 2002.

AAAA
The American Association of Amateur Astronomers
P.O. Box 7981
Dallas, TX 75209-0981
e-Mail: aaaa@astromax.com

www.AstroMax.com