February 18th 2019

Mariner 6 was launched on February 24th 1969 and Mariner 7 on March 27 1969. Mariner 6 and 7 were the second pair of Mars missions in NASA’s Mariner series of solar system exploration in the 1960s and early 1970s. As with the other Mariners, each launched on an Atlas rocket with either an Agena or Centaur upper-stage booster, and weighed less than half a ton (without onboard rocket propellant).

In 1969, Mariner 6 and Mariner 7 completed the first dual mission to Mars, flying by over the equator and south polar regions and analyzing the Martian atmosphere and surface with remote sensors, as well as recording and relaying hundreds of pictures. By chance, both flew over cratered regions and missed both the giant northern volcanoes and the equatorial grand canyon that was discovered later. Their approach pictures did, however, show that the dark features on the surface long seen from Earth were not canals, as once interpreted in the 1800s.

Source: https://mars.nasa.gov/programmissions/missions/past/mariner67/

February 11th 2019

On the evenings surrounding Tuesday, February 12, Mars’ faster eastward orbital motion will carry it closely past Uranus, which will be more than 12 times farther away from Earth. Their smallest separation of only 1 degree (a finger’s width) will happen on Tuesday evening, when the red and blue planets will appear together in the eyepiece of a backyard telescope at low magnification. While much brighter Mars will be north (to the upper right) of Uranus, your telescope might flip the view. (Use the nearby moon to test how your telescope alters the view.)

Source: https://www.space.com/16149-night-sky.html

4th February 2019

February 5th this week will mark the date when Mariner 10 became the first spacecraft ever to test out and execute a technique known as a planetary gravity assisted flyby used to alter its speed and trajectory- in order to reach another celestial body.

Mariner 10 flew by Venus 45 years ago to enable the probe to gain enough speed and alter its flight path to eventually become humanity’s first spacecraft to reach the planet Mercury, closest to our sun.

It was the first spacecraft to visit two planets.

From that moment on, gravity assisted slingshot maneuvers became an extremely important technique used numerous times by NASA to carry out planetary exploration missions that would not otherwise have been possible.

The Mariner 10 probe used an ultraviolet filter in its imaging system to bring out details in the Venusian clouds which are otherwise featureless to the human eye – as you’ll notice when viewing it through a telescope.

Venus’s surface is completely obscured by a thick layer of carbon dioxide clouds.

The hellish planet’s surface temperature is 460 degrees Celsius or 900 degrees Fahrenheit.

Following the completely successful Venus flyby, Mariner 10 eventually went on to conduct a trio of flyby’s of Mercury in 1974 and 1975.

It imaged nearly half of the planet’s moon-like surface, found surprising evidence of a magnetic field, discovered that a metallic core comprised nearly 80 percent of the planet’s mass, and measured temperatures ranging from 187°C on the dayside to minus 183°C on the nightside.

Mercury was not visited again for over three decades until NASA’s MESSENGER flew by and eventually orbited the planet.

Mariner 10 was launched on Nov. 3, 1973 from the Kennedy Space Center atop an Atlas-Centaur rocket.

Shortly after blastoff if also took photos of the Earth and the Moon.

Ultimately it was the last of NASA’s venerable Mariner planetary missions hailing from the dawn of the Space Age.

Mariner 11 and 12 were descoped due to congressional budget cuts and eventually renamed as Voyager 1 and 2.

Source: https://www.universetoday.com/109035/mariner-10-best-venus-image-and-1st-ever-planetary-gravity-assist-40-years-ago-today/

January 28th 2019

The Beehive open star cluster (M44, NGC 2632, also known as Praesepe) will be well placed for observation. It will reach its highest point in the sky at around midnight local time.

At a declination of +19°40′, it is easiest to see from the northern hemisphere; it can be seen at latitudes between 89°N and 50°S.

From Cork, it will be visible in the evening sky, becoming accessible at around 18:39 (GMT) as the dusk sky fades, 16° above your eastern horizon. It will then reach its highest point in the sky at 00:34, 57° above your southern horizon. It will continue to be observable until around 06:28, when it sinks to 16° above your western horizon.

At magnitude 3.1, M44 is tricky to make out with the naked eye except from a dark site, but is visible through a pair of binoculars or small telescope.

Source: https://in-the-sky.org/news.php?id=20190131_16_100&town=2965140

21st January 2019

A total lunar eclipse will take place on 21 January 2019 UTC (Coordinated Universal Time). For observers in the Americas, the eclipse will take place between the evening of Sunday, January 20 and the early morning hours of Monday, January 21. For observers in Europe and Africa, the eclipse will occur during the morning of January 21. The eclipse will occur during a supermoon. It will also be the last total lunar eclipse until May 2021.

The eclipse will be visible in its entirety from North and South America, as well as portions of western Europe and northwest Africa. From locations in North America, the eclipse will begin during the evening hours of January 20. Observers at locations in Europe and much of Africa will be able to view part of the eclipse before the Moon sets in the early morning (pre-dawn) hours of January 21.

Contact points relative to Earth’s umbral and penumbral shadows, here with the Moon near its descending node

The timing of total lunar eclipses are determined by its contacts:

P1 (First contact): Beginning of the penumbral eclipse. Earth’s penumbra touches the Moon’s outer limb.
U1 (Second contact): Beginning of the partial eclipse. Earth’s umbra touches the Moon’s outer limb.
U2 (Third contact): Beginning of the total eclipse. The Moon’s surface is entirely within Earth’s umbra.
Greatest eclipse: The peak stage of the total eclipse. The Moon is at its closest to the center of Earth’s umbra.
U3 (Fourth contact): End of the total eclipse. The Moon’s outer limb exits Earth’s umbra.
U4 (Fifth contact): End of the partial eclipse. Earth’s umbra leaves the Moon’s surface.
P4 (Sixth contact): End of the penumbral eclipse. Earth’s penumbra no longer makes contact with the Moon.

The penumbral phases of the eclipse changes the appearance of the Moon only slightly and is generally not noticeable.

Source: https://en.wikipedia.org/wiki/January_2019_lunar_eclipse

 

January 14th 2019

On Tuesday Near-Earth asteroid 433 Eros makes its closest approach to Earth since 2012 today, when it comes within 19.4 million miles (31.2 million kilometers) of our planet. It glows at 9th magnitude all week and will be bright enough to see through small telescopes. The asteroid resides about 10° southwest of brilliant Capella this evening, a region that lies high in the east after darkness falls. Be sure to catch Eros sometime this month — it won’t be as close or as bright again until 2056.

Source: http://www.astronomy.com/observing/sky-this-week/2019/01/the-sky-this-week-from-january-11-to-january-20

 

7th January 2019

Pluto (minor planet designation 134340 Pluto), will pass very close to the Sun in the sky as its orbit carries it around the far side of the solar system from the Earth.

At closest approach, Pluto will appear at a separation of only 0°07′ from the Sun, making it totally unobservable for several weeks while it is lost in the Sun’s glare.

At around the same time, Pluto will also be at its most distant from the Earth – receding to a distance of 34.71 AU – since the two planets will lie on opposite sides of the solar system.

If Pluto could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 0.0 arcsec in diameter.

Over the following weeks and months, Pluto will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night.

Source: https://in-the-sky.org/news.php?id=20190111_13_100

 

 

31st December 2018

Update: The Ultima Thule flyby was a complete success!

An excellent start to the New Year, the New Horizons probe will flyby Ultima Thule, which will be the most distant object a space probe has ever explored. Ultima Thule is a tiny rock orbiting roughly 4 billion miles (6.5 billion kilometres) from the sun.

“We’ve never in the history of spaceflight gone to a target that we’ve known less about,” Alan Stern, principal investigator of New Horizons and a researcher at the Southwest Research Center in Colorado, told reporters Sunday (December 30th).

But when the spacecraft arrives, it will turn a suite of instruments onto the mysterious object, and many of its mysteries will be unveiled. It’s the second historic rendezvous for New Horizons, which zipped by Pluto in July 2015, the first ever flyby of Pluto.

New Horizons will fly only 2,200 miles (3,500 km) above the surface of the KBO, three times closer than it buzzed Pluto. To help conserve power, several components of the spacecraft will be temporarily turned off, according to Chris Hersman, Missions Systems Engineer at JHU APL. The student dust counter, which picks up roughly one micrometer-sized dust particle per day, and the transmitting portion of one of the radio transmitters. By turning off these tools, the spacecraft will be able to operate its scientific instruments.

In the hours leading up to the flyby, the spacecraft will be pointed at Ultima Thule, unable to communicate with Earth.

“We can’t be in contact with the spacecraft and get data,” said Alice Bowman, New Horizons’ Mission Operation Manager.

Whatever New Horizons reveals, it will definitely be something that has never been seen before.

Source:

https://www.space.com/42864-new-horizons-ultima-thule-flyby-what-to-expect.html

 

24th December 2018

Isaac Newton was born in 1643 in Woolsthorpe, England. His father was a wealthy, uneducated farmer who died three months before Newton was born. Newton’s mother remarried and he was left in the care of his grandmother.

Newton became interested in mathematics after buying a book at a fair and not understanding the math concepts it contained. Newton graduated with a bachelors degree in 1665. The further pursuit of an education was interrupted by the plague. Trinity College was closed due to the highly contagious, deadly disease. Newton went home. It was during this time that Newton started to pursue his own ideas on math, physics, optics and astronomy. By 1666 he had completed his early work on his three laws of motion. The university reopened and Newton took a fellowship in order to obtain his masters degree.

As the years progressed, Newton completed his work on universal gravitation, diffraction of light, centrifugal force, centripetal force, inverse-square law, bodies in motion and the variations in tides due to gravity. His impressive body of work made him a leader in scientific research. However, in 1679 his work came to standstill after he suffered a nervous breakdown. Upon regaining his health Newton returned to the university. He became a leader against what he saw as an attack on the university by King James II. The king wanted only Roman Catholics to be in positions of power in government and academia. Newton spoke out against the king. When William of Orange drove James out of England, Newton was elected to Parliament. While in London he became more enchanted with the life of politics than the life of research. After suffering a second breakdown in 1693 Newton retired from research. He became Warden of the Royal Mint in 1696. He became Master of the Royal Mint in 1699. Newton was very instrumental in developing techniques to prevent counterfeiting of the English money.

Throughout Newton’s career he was torn between his desire for fame and his fear of criticism. His overwhelming fear of criticism caused him to resist immediate publication of his work. As a consequence Newton often felt compelled to defend his work against plagiarism. One such dispute arose over calculus. Though Newton had been the first to derive calculus as a mathematical approach, Gottfried Leibniz was the first one to widely disseminate the concept throughout Europe. The dispute with Leibniz dominated the last years of his life. Newton died in 1727.

Source: https://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level2/newton.html

But was he really born on Christmas Day?

Newton was born in England on Christmas Day 1642 according to the Julian calendar, the calendar in use in England at the time. But by the 1640’s, much of the rest of Europe was using the Gregorian calendar, (the one in general use today); according to this calendar, Newton was born on Jan. 4, 1643. So we have this ambiguity where Isaac Newton could have correctly stated during his entire life that he was born on Christmas day, but according to our modern calendar this is not the case.

Nevertheless I couldn’t resist the idea of having someone of such great importance to astronomy linked with Christmas day, so I’m saying that Isaac Newton was (sort of!) born on Christmas day.

 

 

 

Space News – December 17th 2018

Josep Comas i Sola (17  December 1868 – 2 December 1937) was a Spanish astronomer and discoverer of minor planets, comets, and double stars. He was born of Catalan origin in Barcelona.

He wrote his first astronomy notes at 10, and was only fifteen when he published an article in a French specialist magazine.

He observed planets including Mars  and Saturn, measuring the rotation period of the latter. He wrote some books popularizing astronomy, and was first president of the Sociedad Astrónomica de España y América. He discovered the periodic comet 32P/Comas Solà, and co-discovered the non-periodic comet C/1925 F1 (Shajn-Comas Solà); he is also credited by the Minor Planet Center with the discovery of 11 asteroids during 1915–1930. Comas i Solà is also credited with the discovery of the double star SOL 1.

In 1905, Solà received the Prix Jules Janssen, the highest award of the Société astronomique de France, the French astronomical society. In 1907 he claimed to observe limb darkening of Saturn’s moon Titan, the first evidence that the body had an atmosphere. He was the head of Fabra Observatory since it was established in 1904.

The asteroids 1102 Pepita (from his nickname Pepito) and 1655 Comas Solà are named after him.

Source:

Wikipedia: https://en.wikipedia.org/wiki/Josep_Comas_i_Sol%C3%A0#cite_note-6