Sky Calendar

Moon, Mars, and Saturn
5/2/2012 Most of the night
The waxing Gibbous Moon, Mars, and Saturn form a near perfect line tonight, the Moon at Center, Saturn flanking to the left, and Mars leading the way to the western horizon, on the right.

Moon, Saturn, and Spica
5/3/2012 Most of the night
The near Full Moon approaches Saturn and the bright star Spica, in Virgo.

Eta Aquarid Meteor Shower
5/5/2012 Best after midnight.

Full Moon
5/5/2012 8:36 PM PDT

Third Quarter Moon
5/12/2012 2:48 PM PDT

New Moon
5/20/2012 4:48 PM PDT

Partial Solar Eclipse
5/20/2012 5:13 PM - 7:38 PM PDT
A significant partial solar eclipse crosses southwest Oregon and Northern California in the afternoon hours this day. Along the track of the Moon's shadow, observers will witness an Annular Solar Eclipse. Here in the SF Bay Area we will see a partial eclipse, but one where a signficant amount of the Sun's disk is blocked by the Moon. Not to be missed!

First Quarter Moon
5/28/2012 1:16 PM PDT

Moon and Mars
5/28/2012 Evening
The First Quarter Moon hangs directly beneath Mars. You can also find Saturn farther off to the left, near the bright star Spica.

Moon, Saturn, and Spica
5/31/2012 Most of the night
The waxing Gibbous Moon, Saturn, and the bright star Spica are all close together tonight. In fact, the Moon is nearly grazing Spica--interesting, considering the MOOOOOn is grazing a star whose name means "ear of grain…".

First American In Space
5/5 - 1961
Alan Shepard became the first American in space, aboard the suborbital Mercury 3/Freedom 7, 1961.

Joseph Lockyer Born
5/17 - 
Joseph Lockyer (1836-1920) born. Lockyer discovered the element Helium in the spectrum of the Sun 27 years before it was found on Earth.

Birth of Chabot Observatory
5/21 - 1883
In 1883, the cornerstone of the new Oakland Observatory was laid to house the telescope and other instruments given to the city for a public observatory by Anthony Chabot, the hydraulic engineer and entrepreneur who built the water system for Oakland.

In an Oakland Tribune column on May 22nd, it was accounted that 3000 Oakland school children attended the dedication ceremony, all carrying flowers that they intended to honor Anthony Chabot with. However, they mistook another man--a singer performing at the ceremony as a member of a quartet--as Chabot and showered their floral tribute upon him instead. The singer was buried in flowers and required help from his colleagues to get out. Anthony Chabot is said to have expressed gratitude for the misidentification....

By the time the observatory was rebuilt in 1886, the public was calling it the “Chabot Observatory.”

Kennedy Declares Moon a Goal
5/25 - 1961
In 1961, President John F. Kennedy declared the national goal of landing a man on the Moon and returning him safely to Earth by the end of the decade.

The Phoenix Has Landed!
5/25 - 2008
On this date in 2008, at 4:53 PM PDT, NASA's Phoenix spacecraft landed in the northern polar regions of Mars on a mission to find and analyze ice.

Eddington Tests Einstein's Relativity
5/29 - 1919
In 1919, Arthur Stanley Eddington led a British solar eclipse expedition to test Einstein's prediction (from his General Theory of Relativity) that light is deflected by gravitation.

Full Moon
6/4/2012 4:12 AM PDT

Partial Lunar Eclipse
6/4/2012 1:50 AM - 6:17 AM PDT
The penumbral phase of this partial lunar eclipse begins at 1:50 AM, and the umbral phase begins at 3:09 AM PDT. By 5:02 AM the umbral phase has ended, and the Moon will set at 5:58 AM, before the penumbral eclipse ends at 6:17 AM.

Transit of Venus
6/5/2012 3:04 PM - 9:46 PM PDT
This is the celestial event you don't want to miss--because if you do, you'll never see it again unless you live to the year 2117. Venus will cross the face of the Sun, appearing as a small silhouette marching from one solar limb to the other. Transits of Venus occur in pairs 8 years apart--but those pairs only come every 109 and 121 years. The first of these in our lifetimes was in 2004. This, then, is the last. It was by observations of the Transit of Venus in the 18th and 19th centuries that astronomers were able to determine the distance from the Earth to the Sun, and by extension to all the other planets of the Solar System.

Third Quarter Moon
6/11/2012 3:43 AM PDT

New Moon
6/19/2012 8:03 AM PDT

Summer Solstice
6/20/2012 4:05 PM PDT

First Quarter Moon
6/26/2012 8:31 PM PDT

Moon, Mars, and Saturn
6/26/2012 After sunset
Look to the west to see the First Quarter Moon hanging out between, and slightly below, Mars and Saturn.

Moon, Saturn, and Spica
6/27/2012 After sunset
The waxing Gibbous Moon, Saturn, and the bright star Spica form a tidy triangle this evening. Mars isn't too far off to the right of this trio, or added viewing enjoyment.

Moon and Scorpion Meet
6/30/2012 Most of the night
The nearly Full Moon cruises straight through Scorpio tonight, moving steadily toward the bright orange star Antares.

Oakland Becomes Astronomical City
6/4 - 1886
From an Oakland Evening Tribune article dated June 4, 1886: "Oakland has the only public school department in the world with a fully equipped astronomical observatory." (Referring to Chabot Observatory with its 8" refractor and meridian transit telescopes.)

Earth at Aphelion
6/6 - 
On this day, Earth is at "aphelion"--its farthest distance from the Sun for the year. Earth's orbit is an ellipse, not a circle, and at aphelion Earth is at the pointy end of the ellipse farthest from the Sun, a full 1.017 AU (Astronomical Units) away--well over a million miles more distant than average.

Mars Close-up Pics, First Time
6/14 - 1965
First close-up images of Mars, Mariner 4, US, 1965.

First Woman in Space
6/16 - 1963
Valentina Tereshkova became the first woman in space, and the only woman to solo in space, Vostok 6. USSR, 1963.

First American Woman in Space
6/18 - 1983
Sally Ride became first American woman in space aboard Challenger, US, 1983.

A First Flight
6/20 - 1939
First flight of liquid-fueled rocket plane, Germany, 1939.

Moon of Pluto Discovered
6/22 - 1978
James Christy of the US Naval Observatory discovered Charon, Pluto's first known moon, 1978. Since then, two additional, though much smaller moons, Hydra and Nix, have been discovered orbiting Pluto as well.

Cosmonauts Die During Reentry
6/23 - 1971
Georgi Dobrovolski, Vladislav Volkov, and Viktor Patsayev aboard Soyuz 11 died during re-entry after an otherwise successful first flight to a space station, Salut 1, USSR, 1971.

Charles Messier Born
6/26 - 1730
Charles Messier born, 1730-1817. This French comet hunter is now best known for his catalog of bright nebulae, star clusters, and galaxies – a junk list of fuzzy things in the sky that are NOT comets.

George Hale Born
6/29 - 1868
George Hale, inventor of the spectroheliograph, and founder of the Yerkes, Mount Wilson, and Palomar Mountain Observatories, was born. 1868-1938.

Mercury Greatest Eastern Elongation
7/1/2012 
Mercury is at its greatest visible separation east of the Sun today, and so is at its easist to spot--though "easiest" is still a relative term, as Mercury is always challenging to find in the twilight. Look to the western horizon after sunset to attempt to find it.

Full Moon
7/3/2012 11:52 AM PDT

Third Quarter Moon
7/10/2012 6:50 PM PDT

Moon, Jupiter, Venus, Aldebaran, and Pleaides!
7/14/2012 Before sunrise
Get up early to see this one! By 4:00 AM, you can look low on the Eastern horizon to see a stunning grouping of celestial objects, starting lowest on the horizon with the brilliant planet Venus, which sits very close to the bright orange star Aldebaran, eye of Taurus the Bull. Upward, we find Jupiter, also a bright spot, and bove that a thin, waning Crescent Moon. Finally, above and left of the Moon are the Pleaides star cluster. The set will fade as twilight grows, so don't get up too late….

Moon, Venus, Jupiter, Aldebaran, and the Pleadies
7/15/2012 Before sunrise
A dazzling show of celestial objects similar to yesterday morning is still at play, though the thin waning Crescent Moon has descended a bit, now sitting between Venus and Jupiter and next to Aldebaran, the bright orange "eye" of Taurus the Bull. A bit lonlier now, the Pleaides hangs out above, aloft, apart….

New Moon
7/18/2012 9:25 PM PDT

Moon, Mars, and Saturn
7/24/2012 After sunset
Look to the west after sunset to see the waxing Crescent Moon near Mars and Saturn.

First Quarter Moon
7/26/2012 1:57 AM PDT

Moon and Antares
7/28/2012 Evening
The waxing Gibbous Moon is in Scorpio tonight, not far from the bright orange star Antares, heart of the Scorpion.

Happy Birthday Crab Nebula!
7/4 - 1054 AD
On this day in 1054 AD, a star exploded in the constellation of Taurus. This event was observed and recorded by Chinese and Japanese astronomers, and possibly Puebloan people of the American southwest as well.

Today, the remnants of this great explosion can be seen in Taurus as the beautiful cloud of gas we call the Crab Nebula. Astronomers have used the thousand year old records left by the Chinese and Japanese to study the process of supernovas.

Mars Pathfinder Landing Anniversary
7/4 - 1997
On this day in 1997, the spacecraft Pathfinder landed on Mars.

Newton Publishes Principles
7/6 - 1687 AD
Isaac Newton's Principia Mathematica published in 1687, UK.

Alvan Clark's Birthday
7/10 - 1832
Alvan Clark and Sons was the telescope-making company responsible for building Chabot Observatory's first telescope, the 8-inch refractor later named Leah.

First Private Satellite Launched
7/10 - 1962
First private communications satellite, Telstar, launched. US, 1962.

Skylab Takes the Plunge
7/11 - 1979
Skylab, the first US space station, is destroyed on re-entry into the Earth's atmosphere.

Mariner Flies by Mars
7/14 - 1965
First controlled flyby and close-up images of Mars. Mariner 4, US, 1965

Apollo/Soyuz Launch
7/15 - 1975
First joint US/USSR mission launched into orbit, i>Apollo/Soyuz, 1975. See also 17 July.

Apollo/Soyuz Rendezvous
7/17 - 1975
First US/USSR docking in space, Apollo/Soyuz, 1975.

First Humans on the Moon
7/20 - 1969
Neil Armstrong and Buzz Aldrin became the first humans to set foot on another world, the Moon. Apollo 11, US, 1969.

Viking Lands on Mars
7/20 - 1976
Viking 1 set down on Mars and returned the first images from the surface. US, 1976.

First Rocket Fired from Canaveral
7/24 - 1950
First rocket launched from Cape Canaveral, Bumper 8, a V-2/WAC-Corporal two-stage combination, US, 1950.

NASA Founded
7/29 - 1958
National Aeronautics and Space Administration, NASA, founded. US, 1958.

Ranger 7 Surveys Moon
7/31 - 1964
First close-up images of the Moon, Ranger 7, US, 1964.

Alpha Capricornid Meteor Shower
8/1 - Best after midnight
The annual Alpha Capricornid meteor shower peaks this night. Best viewing occurs after midnight, though meteors can be seen at any time of the night. The region of the sky from where these meteors appear to radiate (the "radiant") is in the constellation Capricorn, which rises in the southeast around the time of sunset and will be almost directly south around 1:00 AM, about 35 degrees above the horizon. This shower typically yields from 6-14 meteors per hour, and is known to produce some of the brightest meteors of the major showers.

Maria Mitchell Born
8/1 - 1818
Maria Mitchell born in 1818. She was the first woman elected as an astronomer to the American Academy of Arts and Sciences after her 1847 discovery of a bright comet.

Apollo 15 Launches Satellite
8/3 - 1971
First satellite launched into lunar orbit from a manned spacecraft, Apollo 15, US, 1971.

First Spectroscopic Study of a Comet
8/5 - 1864
First spectroscopic observations of a comet (Comet Tempel). Giovanni Donati, 1864.

The comet in the picture is Hale-Bopp.

Neil Armstrong Born
8/5 - 1930
Neil Armstrong, first human to walk on the moon, born in 1930.

First Images of Earth from Orbit
8/7 - 1959
First images of Earth returned from orbit, Explorer 6, US, 1959.

Deimos Discovered
8/11 - 1877
Mars's outer moon Deimos discovered. Asaph Hall, U.S. Naval Observatory, 1877. See also 17 August.

Angstrom Born
8/13 - 1813
A. J. Angstrom, Swedish physicist and spectroscopist, born in 1814. The Angstrom, a unit of length equal to 0.1 nanometers, is named for him.

Mars' Moon Phobos Discovered!
8/17 - 1877
On this date in 1877, astronomer Asaph Hall discovered Phobos, the larger of Mars' two moons.

Helium Discovered--On the Sun!
8/18 - 1868
Norman Lockyer discovered helium in the Sun's spectrum in 1868. The element would not be found on Earth until 1895 (by William Ramsay, a Scottish chemist).

Chabot Space & Science Center Opens!
8/19 - 2000
Happy Birthday Chabot Space & Science Center!

Flamsteed Born
8/19 - 1646
John Flamsteed, first Astronomer Royal of England, and founder of Greenwich Observatory, born in 1646.

Milton Humason Born
8/19 - 
Milton Humason born in 1891. A colleague of Edwin Hubble at Mount Wilson and Palomar Mountain, Humason's measurements of faint galaxy spectra provided evidence for the expansion of the universe.

Farewell, Planet Pluto!
8/24 - 
On this day in 2006, Pluto's 76-year career of being the Ninth Planet, the only planet discovered from the Americas, and the only planet discovered in the 20th Century, came to an end. The International Astronomical Union (IAU) voted on a proposal for a scientific definition of a planet, and the version of the definition that passed created an exclusive club of eight planets--ending, for the time being, with Neptune. Pluto, along with Ceres and the newly discovered Eris, are now members of their own club: Dwarf Planets.

Voyager Visits Neptune`
8/25 - 1989
Voyager 2 flies by Neptune, US, 1989.

Voyager Visits Saturn
8/25 - 1981
Voyager 2 flies by Saturn, US, 1981.

Enceladus Discovered
8/28 - 1789
Saturn's moon Enceladus discovered. William Herschel, 1789.

Chabot's New Director
9/1 - 1923
After the death of Charles Burckhalter, Earle Linsley is appointed as Director of Chabot Observatory.

First Flyby of Saturn: Pioneer 11
9/1 - 1979
First flyby of Saturn and return of close up images, Pioneer 11, US, 1979.

First Solar Flare Recorded
9/1 - 1859
First solar flare ever recorded observed by solar physicist Richard Carrington in 1859.

Viking 2 Lands on Mars
9/3 - 1976
Viking 2 lander touched down on Mars, about 7 weeks after Viking 1 (July 20), US, 1976.

AAS Founded
9/6 - 1899
American Astronomical Society founded in 1899 as the Astronomical and Astrophysical Society of America.

To Boldly Go
9/8 - 1966
Star Trek uses high production values to boldly go where no TV science fiction show has gone before, inspiring a generation's interest in space, astronomy, technology, and alternative social systems -- US, 1966.

Amalthea Discovered
9/9 - 1892
Amalthea, Jupiter's innermost moon, discovered by Edward Emerson Barnard, Lick Observatory, 1892. It was the first of Jupiter's moons to be discovered since Galileo found the first four in 1609. Jupiter is now known to have 28 moons-- and counting....

First Glass Plate Photo
9/9 - 1839
First photograph on a glass plate taken by John Herschel, 1839 The subject of the photo was the famous 48-inch aperture telescope of John's father, William Herschel, in disuse for several decades and shortly to be dismantled.

James E. Keeler Born
9/10 - 1857
James E. Keeler, pioneer American spectroscopist and astrophysicist, born in 1857. In 1895, he showed that different parts of Saturn's rings rotate at different velocities, proving the rings to be not solid bodies, but instead systems of many tiny objects in independent orbits.

First Flyby of a Comet
9/11 - 1985
First flyby of a comet( Comet Giacobini-Zinner), ICE, the International Cometary Explorer, US, 1985. ICE was the former International Solar Explorer, reprogrammed for this mission.

Sir James Jeans Born
9/11 - 1877
Sir James Jeans, English astronomical theoretician, born in 1877. He proposed that stars created energy by the destruction of matter in accordance with Einstein's formula, E = mc².

First Human-made Object Strikes Moon
9/12 - 1959
First manmade object to strike the moon, Luna 2, USSR, 1959.

Mimas Discovered
9/17 - 1789
Saturn's moon Mimas discovered in 1789 by William Herschel.

Hyperion Discovered
9/19 - 1848
Saturn's moon Hyperion discovered by William Boyd in 1848.

Israel Launches First Satellite
9/19 - 1988
Israel became the ninth nation to launch a satellite, Ofec 1, 1988.

Andromeda Galaxy Say Cheese!
9/20 - 1948
First 48-inch Schmidt photographic plate taken, Palomar Mountain, 1948. M31, the Andromeda Galaxy, was the subject.

Neptune Discovered
9/23 - 1846
1846 - Neptune first observed by Johann Galle, Berlin Observatory, using the position predicted by French mathematician Urbain Leverrier.

Lunar Material Returned Automatically
9/24 - 1970
First automated return of lunar material to Earth, Luna 16, USSR, 1970.

Orion Nebula First Photographed
9/30 - 1880
First photo of the Orion Nebula (M42), Henry Draper, 1880.

NASA Inaugurated
10/1 - 1958
The National Aeronautics and Space Administration, NASA, was inaugurated on this date in 1958.

First Long-Range Rocket
10/3 - 1942
First successful launch of the A4, or V2, the first long-range rocket. Germany, 1942.

Sputnik Launched, 1957
10/4 - 1957
The USSR launched Sputnik 1, the first artificial satellite, marking the dawn of the Age of Space. 1957.

Robert Goddard Born
10/5 - 1882
Robert Goddard (1882-1945), American rocket pioneer, was born on this date. He launched the world's first liquid-fuel rocket from his Aunt Effie's Auburn, Massachusetts, farm in 1926, and anticipated many of the technical advances that made space flight possible.

First Extra-solar Planets Detected, 1995
10/6 - 1995
On this date in 1995, Swiss astronomers Michel Mayor and Didier Queloz discover planets orbiting the sun-like star 51- Pegasi. Since then more than 40 extra-solar system planets have been discovered.

Ejnar Hertzsprung's Birthday
10/8 - 
Danish astronomer Ejnar Hertzsprung was born on this day in 1873. Hertzsprung and American astronomer Henry Norris Russell independently conceived a graph which plotted the temperatures of stars against their luminosities. This graph has come to be known as the Hertzprung-Russell Diagram and has become one of the astronomers most important tools in understanding stars and their evolution.

Triton Discovered
10/10 - 1846
Triton, the first known moon of Neptune, was discovered by William Lassell of England in 1846.

Apollo 7 Launched
10/11 - 1968
The US launched Apollo 7, the first human-crewed Apollo mission, into Earth's orbit, US, 1968.

First Supersonic Flight
10/14 - 1947
Charles Yeager made the first supersonic flight aboard the Bell X1 rocket plane, US, 1947.

Orionid Meteor Shower
10/21 - Oct 21-22
The Orionid Meteor Shower reaches its peak activity tonight. At its peak, the number of Orionids that are seen is around 25 per hour. This is one of two meteor showers that are associated with Comet Halley. The other meteor shower associated with Comet Halley is the Eta Aquarids, which are seen on or about May 5.

First Images from Surface of Venus
10/22 - 1975
The first images were returned from the surface of Venus by Venera 9, USSR, 1975.

Harlow Shapley Born
11/2 - 1885
Harlow Shapley (1885-1972) born on this date. Before Shapley, the majority of astronomers believed the Universe consisted of a Milky Way Galaxy about 30,000 light years across with the Sun and the Solar System not far from the center. In 1918, Shapley found that the Galaxy was much larger and that the Sun was far from the center. (Edwin Hubble would soon demonstrate that this greatly enlarged Milky Way was but one of billions of galaxies in a much vaster Universe.)

First Earthling in Space
11/3 - 1957
On this date in 1957 a dog, named Laika, became the first Earth creature to fly in space. Laika, along with some other dogs, were recruited into the Soviet space program from the streets of Moscow.

First Flyby of Jupiter
11/3 - 1973
First flyby of Jupiter and close-up images, Pioneer 10, US, 1973.

Goddard Launches a Rocket
11/7 - 1918
American rocket pioneer Robert Goddard demonstrated tube-launched solid-fuel rockets in 1918, the basis for WWII's "bazooka" anti-tank weapon.

Edmund Halley Born
11/8 - 1656
On this day in 1656, Edmund Halley was born. Though he did not discover the comet that bears his name, his prediction of its return proved that comets were objects of the Solar System and, like the planets, orbited the Sun.

Mariner 9, a Pioneer
11/13 - 1971
First spacecraft to orbit another planet, Mars, Mariner 9, US, 1971.

Sir William Herschel Born
11/15 - 1738
Sir William Herschel was born on this date in 1738. Herschel’s discovery of Uranus marked the first time a planet was known to exist beyond the orbit of Saturn. At the time of the discovery, Herschel wanted to name the planet Georgium Sidus (“George’s Star”) after his patron, King George III of England. However, in keeping with the earlier tradition of naming the planets after the Roman gods of mythology, the planet was named Uranus. According to Roman mythology, Uranus was the father of Saturn and the grandfather to Jupiter. Jupiter, in turn, was father to the Sun and the other planets except the Earth.

First Long Distance Call--sort of
11/16 - 1974
First intentional interstellar radio signal sent from Earth, US, 1974. The message, a pictographic greeting, was sent toward M13, a globular star cluster some 21,000 light years away in Hercules, during the dedication of the Arecibo Radio Telescope. Expect a reply in 42,000 years...

Venera 3 Launched, 1965
11/16 - 1965
On this date in 1965, the Soviets launched Venera 3 to Venus.

Edwin Hubble Born
11/18 - 1889
Edwin Hubble (1889-1953) born in this date. He proved that the Universe is filled with galaxies like our Milky Way, and that it is expanding.

Pioneer Baloonists
11/21 - 1783
First humans to fly in a balloon, Pilatre de Rozier and the Marquis D'Arldes of France, 1783.

Oakland Observatory Opens to Public
11/24 - 1883
The new Oakland Observatory (later called Chabot Observatory, after Anthony Chabot, its funder) opens to the public. With its 8-inch refracting telescope, manufactured by Alvan Clark and Sons, the observatory begins its mission of offering astronomical views of the heavens to public visitors and Oakland school children.

First French Satellite
11/26 - 1965
France became the third nation to launch a satellite, Asterix, in 1965.

First Spacecraft to Impact Mars
11/27 - 1971
First spacecraft to impact the planet Mars, Mars 2, USSR, 1971.

Chimp In Space!
11/29 - 1961
Mercury 5 launched to orbit with a chimpanzee passenger named Enos, US, 1961.

First Soft Landing on Mars
12/2 - 1971
On this date in 1971, the USSR's Mars 3 achieved the first soft landing of an uncrewed vehicle on Mars, and transmitted the first radio signals from the surface of Mars.

First Spacecraft to Orbit Venus
12/4 - 1978
On this date in 1978, Pioneer Venus 1 became the first craft to orbit Venus.

Last Apollo Moon Landing
12/7 - 1972
Last humans to visit the Moon (in the 20th Century, at least) launched, Apollo 17, the sixth and last Apollo moonflight, US, 1972. Let's do it again.

Birthday of Annie Jump Cannon
12/11 - 1863
Among Annie Jump Cannon's long list of accomplishments in astronomy, she is known for having studied and catalogued a long list of variable stars, 300 of which she discovered. She also devised the lettering system for the classification of main sequence star types based on mass and temperature, the well known scale O B A F G K M, O standing for the most massive and hottest blue stars, M for the smallest, coolest, reddest stars.

Tycho Brahe Born
12/14 - 1546
Tycho Brahe (1546-1601) born on this date. Tycho, the last great pre-telescopic astronomer, made more accurate measurements of the positions of the stars and planets by a factor of 10 than had ever been made, and provided the data from which Johannes Kepler would discover his Laws of Planetary Motion.

First Soft Landing on Venus
12/15 - 1970
On this date in 1970, the USSR's Venera 7 achieved the first soft landing of an uncrewed vehicle on Venus, and transmitted the first radio signals from the surface of Venus.

Wilbur and Orville Fly!
12/17 - 1903
On this date in 1903, Wilbur and Orville Wright made the first powered, heavier-than-air flight on the Wright Flier.

First Voice Broadcast from Space
12/18 - 1958
On this date in 1958, the first voice broadcast from space was made from the Atlas Score: a pre-recorded Christmas message by President Eisenhower.

First Humans Orbit Moon
12/24 - 1968
On this date in 1968, the first humans orbit Moon in Apollo 8. Frank Borman, James A. Lovell, Jr. and William Anders were the crew of Apollo 8.

Isaac Newton Born
12/25 - 1642
Isaac Newton (1642-1727) born on this date (Julian calendar, it would have been 5 Jan 1643, Gregorian). He discovered that white light is made up of the colors of the rainbow, invented calculus, and demonstrated that the motions of the planets are governed by the same laws of motion and gravity as the motions of things on Earth. His Philosophiae Naturalis Principia Mathematica, the Mathematical Principals of Natural Philosophy, (the Principia) has been called the most important book on science ever written.

Johannes Kepler Born
12/27 - 1571
Johannes Kepler was born on this date in 1571. Kepler used Tycho Brahe's observations to discover Kepler's Laws of Planetary Motion: 1. Planets orbit in elliptical paths with the Sun at one focus. 2. A line connecting the Sun to a planet sweeps out equal areas in equal times. 3. The cube of a planet's period of revolution around the Sun is proportional the square of its average distance from the Sun.