
Ground image of Nereid. |
May 1st: Day 121 of the Gregorian calendar.
History: In 1949, Gerard Kuiper discovered Nereid on photographic plates taken with the 82-inch telescope at the McDonald Observatory. Nereid is the most external and the third biggest known moon of Neptune. He proposed the name in the report of his discovery. It is named after the Nereids, sea-nymphs of Greek mythology and attendants of the god Neptune. It was the second and last moon of Neptune to be discovered before the arrival of Voyager 2 (not counting a single observation of an occultation by Larissa in 1981).
Observations: If the air is very clear, before dawn you can see a thin crescent Moon clustered with Venus, Jupiter, Mercury and Mars at the eastern side of the sky.
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May 2nd: Day 122 of the Gregorian calendar.
Observations: Binoculars will show a thin crescent Moon about 11º left of Jupiter, very low in east just before sunrise. |

Baily's beads. |
May 3rd: Day 123 of the Gregorian calendar.
History: It is sometimes said that in 1715, during an eclipse, Edmond Halley was the first to make a record of the phenomena that later was dubbed as Baily's beads (because they were undoubtedly seen by Francis Baily in 1836); he also observes the bright red prominences and the east-west asymmetry of the corona, that he assumes to be generated by an atmosphere of the Moon or of the Sun.
Observations: New Moon at 6h51 (UTC) |

Magellan probe being launched.
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May 4th: Day 124 of the Gregorian calendar.
History: In 1989 the NASA mission Magellan was launched to Venus. Its task was to obtain high resolution images of the planets's surface. The Magellan spacecraft, is also referred to as the Venus Radar Mapper, was launched to map the surface of Venus using Synthetic Aperture Radar and measure the planetary gravity. It was the first interplanetary mission to be launched from the Space Shuttle, the first to use an inertial upper stage booster and was the first spacecraft to test aerobraking as a method for circularizing an orbit. Magellan was the fourth successful, NASA funded mission to Venus and ended an eleven year U.S. interplanetary exploration hiatus.
Observations: The Pleiades are close to the thin crescent Moon at west-northwest at dusk's twilight fading. |
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May 5th: Day 125 of the Gregorian calendar.
History: In 1961, Alan Shepard becomes the first American in space traveling on the spaceship Freedom 7.
Observations: This evening after midnight time to see the Eta Aquarid meteor shower. |
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May 6th: Day 126 of the Gregorian calendar.
Observations: The Eta Aquarid meteor shower will be visible in early morning before dawn. |

SS Endeavour launch.
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May 7th: Day 127 of the Gregorian calendar.
History: In 1973, the X-ray Space Observatory Explorer 53 was launched.
In 1992, Space Shuttle Endeavour was launched. Endeavour was the fifth and final space worthy NASA space shuttle to be built, constructed as a replacement for Challenger.
In 1997, the Galileo probe made its fourth flyby to Ganimedes. Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989 by the Space Shuttle Atlantis on the STS-34 mission. It arrived at Jupiter on December 7, 1995, a little more than six years later, via gravitational assist flybys of Venus and Earth.
Observations: In May, the Big Dipper is upside-down very high in the northern sky. Its "handle" pints out to bright Arcturus. Arcturus is a giant yellow-orange star of the spectral type K1.5 III. |

.Atlas Centaur. |
May 8th: Day 128 of the Gregorian calendar.
History: In 1962, the first rocket Atlas Centaur was launched. The Atlas-Centaur was an !merican expendable launch system designed and built by the General Dynamics Convair Division. It was derived from the SM-65 Atlas missile. It was used for 61 orbital launches between 1962 and 1983.
Observations: Can you find the Hercules constellation? How about trying to spot M13? |

The trail Alkaid-Arcturus-Spica. |
May 9th: Day 129 of the Gregorian calendar.
History: In 1931, Albert Abraham Michelson
died. Michelson was born in Strzelno, Provinz Posen in the Kingdom of Prussia (now Poland) but he moved to the United States with his parents in 1855, when he was only two years old. He is mostly known for his work on the measurement of the speed of light and especially for the Michelson-Morley experiment a crucial evidence to support the foundations of relativity. In 1907 he received the Nobel Prize in Physics.
Observations: Follow the tail of the Big Dipper and you will find the star Arcturus (Alpha-Bootes). If you continue the arch you will find the star Spica (Alpha Virgo). You can click on the image on the left to see a larger version that can help you more. |
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May 10th: Day 130 of the Gregorian calendar.
History: In 1971 Kosmos 419 (USSR) was launched without success. It was unable to reach Earth's orbit.
Observations: First Quarter of the Moon at 20h33 (UTC). |

Karl Schwarzschild
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May 11th: Day 131 of the Gregorian calendar.
History: In 1918 Richard Feynman, was born. Feynman was an !merican physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics. For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Sin-Itiro Tomonaga, received the Nobel Prize in Physics in 1965. He was also a popularizer of physics through books and lectures, notably with The Feynman Lectures on Physics. Feynman also became known through his semi-autobiographical books (e.g. Surely You're Joking, Mr. Feynman!).
In 1916 Karl Schwarzschild died. He is best known for providing the first exact solution to the Einstein field equations of general relativity. The Schwarzschild solution, which makes use of Schwarzschild coordinates and the Schwarzschild metric, leads to the well-known Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole.
Observations: At dawn Jupiter is 0.5º above Venus and Mercury is 0.5º bellow Venus. Mars is less that 5º to the left (facing East, of course). |

Luna lander.
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May 12th: Day 132 of the Gregorian calendar.
History: In 1965, the soviet probe Luna 5 colides on the Moon. It was the second Russian spaceship to reach the Moon after Luna 2. Luna 5 had been the first Soviet probe to head for the Moon in two years due to successive failures after the launch of Luna 4. Following the mid-course correction that was supposed to be done on May 10th, the spacecraft began spinning around its main axis due to a problem in a flotation gyroscope. A subsequent attempt to fire the main engine failed because of ground control error. With no engine to help the engine crashed at Lunar coordinates of 31° south latitude and 8° west longitude.
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Earthshine.
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May 13th: Day 133 of the Gregorian calendar.
History:. In 1733, during a solar eclipse the Swedish astronomer Bigerus Vassenius was the first to notice the Earthshine on the Moon during totality.
In 1999, project SETI@Home was launched.
Observations: The Moon is at Saturn's lower right. |
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Skylab on Saturn V rocket.
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May 14th: Day 134 of the Gregorian calendar.
History: In 1973 Skylab the first American space station was launched. This launch was the last trip of a Saturn V rocket. Skylab was the United States' first space station, and the second visited by a human crew after the Soviet Salyut 1. The only station NASA has launched independently. Starlab reentered Earth's atmosphere and disintegrated in 1979 in an event that was followed at global scale due to the possibility of uncontrolled reentrance that might be dangerous for population. It finally felt in the ocean, with debris striking portions of Western Australia.
Observations: The Moon is at Spica's lower right. |

Nicolas Lacaille.
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May 15th: Day 135 of the Gregorian calendar.
History: In 1713, Nicolas Louis de Lacaille was born. He calculated a table of eclipses for 1800 years. He is noted for his catalogue of nearly 10,000 southern stars, including 42 nebulous objects. This catalogue, called Coelum Australe Stelliferum, was published posthumously in 1763. It introduced 14 new constellations which have since become standard. The crater La Caille on the Moon and Asteroid 9135 Lacaille (AKA 7609 P-L and 1994 EK6), discovered on 17 October 1960, were named after him.
In 1958, Sputnik 3 was launched.
In 1960, USSR launched Sputnik 4.
In 1963, the last mission of the Mercury Project, Mercury-Atlas 9, was launched with the astronaut Gordon Cooper on board.
Observations: Mercury remains 1.5º from Venus. During the next 5 days Mars will be closer than 5º to their left. |

Comet Hale-Bopp.
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May 16th: Day 136 of the Gregorian calendar.
History: In 1969, the soviet probe Venera 5 lands on Venus. Venera 5 was launched from a Tyazheliy Sputnik towards Venus to obtain atmospheric data. A capsule weighing 405 kg and containing scientific instruments was jettisoned from the main spacecraft while approaching Venus. Satellite descent towards the surface of Venus, on May 16, 1969, was slowed down using a parachute that allowed 53 minutes of data recollection from the Venusian atmosphere that were emitted back to Earth.
In 1997, the STS-84 docks on MIR for the sixth STS-MIR.
In the same year the internet is filled with images of the Hale-Bopp comet. Comet Hale–Bopp (C/1995 O1) was arguably the most widely observed comet of the 20th century, and one of the brightest seen for many decades. It was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Though the previous year's comet Hyakutake was the longest tail comet, Hale-Bopp remained longer in the sky, with more favorable conditions and had a wider impact on general public specially in Europe.
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Norman Lockyer
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May 17th: Day 137 of the Gregorian calendar.
History: In 1836 Joseph Norman Lockyer was born. He was fascinated by electromagnetic spectroscopy as an analytical tool for determining the composition of heavenly bodies. On his research (which was done from his home in West Hampstead) he discovered a spectral line with a wavelength of about 588 nm, slightly less than the so-called "D" lines of sodium. This line could not be explained as due to any material known at the time. Therefore Lockyer suggested that the yellow line was caused by an unknown solar element. He named this element helium after the Greek word 'Helios' that was the name of Sun.
In 1882 a comet was discovered in pictures of the solar corona made during an eclipse.
In 1969, the soviet probe Venera 6 begins its approach to Venus' atmosphere collecting data before its destruction.
Observations: Full Moon at 11h09 (UTC). |

Apollo 10 crew.
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May 18th: Day 138 of the Gregorian calendar.
History: In 1910, Earth passed by the tail of comet Halley. Halley's comet is the best-known of the short-period comets, and is visible from Earth every 75 to 76 years. It has been observed and recorded by astronomers since at least 240 BC and its periodicity was first determined in 1705 by English astronomer Edmond Halley. Its next next appearance will be in mid-2061.
In 1969 Apollo 10 was launched. According to the Guinness Book of Records, Apollo 10 has the record of the highest speed that was set by a crewed vessel with 39,897 km/h. This speed was obtained when the ship was returning from the Moon on May 26th, 1969.
Observations: Take the night to try to make a nice picture of Saturn with your telescope. |

Cecilia Payne-Gaposchkin.
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May 19th: Day 139 of the Gregorian calendar.
History: In 1900 Cecilia Helena Payne-Gaposchkin was born. In 1925 she was first to show that the Sun is mainly composed of hydrogen, contradicting accepted wisdom at the time. Astronomer Otto Struve characterized it as "undoubtedly the most brilliant Ph.D. thesis ever written in astronomy". By applying the ionization theory developed by Indian physicist Saha she was able to accurately relate the spectral classes of stars to their actual temperatures. She showed that the great variation in stellar absorption lines was due to differing amounts of ionization that occurred at different temperatures, and not due to the different element's abundance.
In 1971 the Mars 2 probe (USSR) was launched.
Observations: Try to observe the Perseus Double Cluster (find how). |

Vasco da Gama. |
May 20th: Day 140 of the Gregorian calendar.
History: In 1498, Vasco da Gama reached Calcuta (India) on a journey that like Columbus journey to America was the equivalent to the modern space odysseys.
Observations: At dawn Venus, Mercury and Mars form a small triangle. |
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May 21st: Day 141 of the Gregorian calendar.
Observations: At dawn Venus, Mercury and Mars still form a small triangle. It's predictable that this morning this triangle is only about 2º wide. |
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May 22nd: Day 142 of the Gregorian calendar.
History: In 1969, the lunar module of Apollo 10 passed at 8 nautical miles (16 km) from the surface of the Moon.
Observations: Mars is about 1º above Venus. |

Explorer 1. |
May 23rd: Day 143 of the Gregorian calendar.
History: In 1958, the satellite Explorer 1 stopped emissions. Explorer 1 was the first Earth satellite launched by the United States of America as part of its participation in the International Geophysical Year. It was also the third ship in space following the previous year's satellites Sputnik 1 and Sputnik 2 launched by USSR. Its launch marked the beginning of the Space Race between these two nations.
Observations: Mars is about 1º above Venus and Mercury is less than 4º to their lower left. |

Copernicus.
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May 24th: Day 144 of the Gregorian calendar.
History: In 1543 Nicolaus Copernicus dies. Copernicus was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the Universe. Though his theory was generally accepted by the end of the 17th Century, due to the work of Kepler and Galileo, Earth's translation was only experimentally proved in the 19th Century (using Doppler effect, parallax measurements and stellar aberration) as well as rotation (Foucault's pendulum, Coriolis Force evidences and Eccentricity).
In 1962, the American astronaut Scott Carpenter of the project Mercury orbits Earth three times on the space capsule Aurora 7.
Observations: Last Quarter of the Moon at 18h52 (UTC). |

Titan.
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May 25th: Day 145 of the Gregorian calendar.
History: In 1665 Christiaan Huygens discovered Titan, Saturn's largest moon. Titan is the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found.
In 1992, the cosmonaut Sergei Krikalev returned to Earth after a 10 month mission on the Mir Space Station.
Observations: Don't forget to work on your projects for "Catch a Star". |
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May 26th: Day 146 of the Gregorian calendar.
History: In 1958, the United States Army launches Explorer 3. |

Discovery launch
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May 27th: Day 147 of the Gregorian calendar.
History: In 1999, the mission STS-96 of the Space Shuttle Discovery was launched. STS-96 was the mission flight when Discovery became the first Orbiter Shuttle to dock with the International Space Station Discovery was one of the Orbiters in the Space Shuttle team of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on 30 August 1984 until its final landing, STS-133 on 9 March 2011.
Observations: If you have a really dark sky then tray to observe the Virgo Cluster. Start by the easiest object M60. |

Mars 3.
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May 28th: Day 148 of the Gregorian calendar.
History: In 1959, two monkeys,Able & Baker, traveled at an altitude of 580 km for 16 minutes.
In 1971 the probe Mars 3 (USSR) was launched.
In 1998, the asteroid 1998 KY26 was discovered by Tom Gehrels.
In 2002, Mars Odyssey discovered ice deposits on Mars. |

Luna 22.
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May 29th: Day 149 of the Gregorian calendar.
History: In 1919, a total solar eclipse was observed by two groups of astronomers to try to confirm the Einstein's General Relativity Theory.
In 1974 the Luna 22 (USSR) probe was launched.
In 1999, Discovery Space Shuttle completes its first docking on the International Space Station.
Observations: The waning crescent Moon is upper left of Jupiter at dawn. |

Surveyor 1.
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May 30th: Day 150 of the Gregorian calendar.
History: In 1966, Surveyor 1, the first American probe to land on the Moon was launched.
In 1971 Mariner 9 was launched.
Observations: The waning crescent Moon is upper right of Venus at dawn. |

Jupiter and Io
(eclipsing the Sun) viewed from Cassini.
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May 31st: Day 151 of the Gregorian calendar.
History: In 2001, the Cassini probe ends its flyby to Jupiter and goes on to Saturn. Cassini–Huygens was a joint NASA/ESA/ASI robotic spacecraft mission that ended studying planet Saturn and its many natural satellites. The spacecraft consisted of two main elements: the NASA-designed and -constructed Cassini orbiter, named for the Italian-French astronomer Giovanni Domenico Cassini, (also known later as Jean-Dominique Cassini when he became a citizen of France), and the ESA-developed Huygens probe, named for the Dutch astronomer, mathematician and physicist Christiaan Huygens. The complete Cassini space probe was launched on October 15, 1997, and after a long interplanetary voyage it entered into orbit around Saturn on July 1, 2004.
Observations: The waning crescent Moon is clustered with Venus and Mercury at dawn immediately before sunrise (hard to see).
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