Archive for the ‘Astronomy blog’ Category

Daily cosmobite: A breakout of solar filaments

Published by Andrew Jacob on February 12, 2015 No Comments

SunandFilament.2015FEB07Several filaments, dark snake-like streaks, appear on the Sun today. These long streams of hot gas ‘float in the magnetic field above the Sun’s surface. APOD for 2015 Feb 10 claims one is amongst the longest ever recorded and it has been there for a week already.

Photographing the Sun with an iPhone is hard. Better views are had during our public solar viewing tours. Photo Andrew Jacob, Sat Feb 07, 2015 © MAAS, Sydney.

 

 

 

 

Daily cosmobite: Centenary of birth of Richard Hamming

Published by Andrew Jacob on February 11, 2015 No Comments

Richard_Hamming.wiki.BellLabsRichard Hamming, mathematician, was born on Feb 11, 1915. Among other things he devised the Hamming window – a mathematical filter used in digital signal processing, whose name will be recognised by many engineers and physicists.

 

 

Richard Hamming, 1915-1998. Photo by Bell Labs.

 

 

 

Daily cosmobite: Dark observing locations in Melbourne

Published by Andrew Jacob on February 10, 2015 No Comments

MelbourneAtNight.ISSLight pollution is the bane of city-based astronomers. This series of night time images was taken from the International Space Station. They help identify dark sites from which to best view the sky. This week we look at Melbourne.

Melbourne at night as seen from the International Space Station, 04 April 2012. ESA/NASA.

Daily cosmobite: Jupiter’s moons, occultations and eclipses

Published by Andrew Jacob on February 9, 2015 No Comments

Jupiter-Moons.NLUntil July Jupiter’s moons will undergo a series of mutual eclipses and occultations. These happen every six years when the orbital plane of the moons appears edge-on to Earth.

Jupiter’s moons are clearly visible through the telescopes at Sydney Observatory. This simulates the view far better than my iPhone pictures! Diagram by Nick Lomb using Stellarium.

 

 

 

Daily cosmobite: Sydney Observatory’s location

Published by Andrew Jacob on February 6, 2015 No Comments

SydneyObservatoryTimeballIn the 1850s plans were afoot to establish a time ball somewhere in Sydney. Captain Phillip Parker King recommended “…the  ground about Fort Phillip because it is visible from all parts of the harbour and city”.

 

Sydney Observatory’s location was primarily determined by the need for the time ball to be visible. ©MAAS.

 

 

 

 

Daily cosmobite: The Giant Magellan Telescope

Published by Andrew Jacob on February 5, 2015 No Comments

Still-GMT-S21-mediumAustralia is part of the Giant Magellan Telescope project, one of the next-generation telescope projects currently in development. Its seven primary mirrors have an equivalent diameter of 24.5m. It will try to answer such questions as: Are we alone? and What is the fate of the universe?

 

The Giant Magellan Telescope will be built at Las Campanas Observatory in Chile. ©GMTO.

 

Scorpius.StellariumThe constellation of Scorpius the scorpion in the southern winter sky. Image made with Stellarium

In 2014 Dr Louise Pryke investigated the well-known zodiacal constellation of Taurus, the Bull. In her most recent research Dr Pryke has been exploring the ancient myth and astrological traditions surrounding the constellation Scorpius. 

When early humans first began to look up at the stars, and to tell stories about the great beings they saw among the constellations, scorpions had already inhabited the Earth for hundreds of millions of years. Religion and astrology were tightly intertwined in the ancient world. Four thousand years ago, the movements and relative positions of Scorpius were useful for the work of Babylonian magicians and astrologers, who left written records of the omens they observed, including cosmological traffic updates!

When a halo surrounds the Moon and Scorpio stands in it, it will cause men to marry princesses, (or) lions will die, and the traffic of the land will be hindered.

A comet appearing in the constellation was considered by astrologers to warn of a plague, but when the Sun rose in Scorpius, it was thought by alchemists to be the only time when the transmutation of lead into gold could occur. The Babylonian word for Scorpius,zuqaqipu, means scorpion. The word is formed from the Akkadian verb zuqapu meaning ‘to fix upright.’ In the Mesopotamian Epic of Gilgamesh, Scorpion people guard the path of the Sun, identified with the solar deity Shamash.

The appearance of scorpions in Greek and Roman myths may suggest an oriental influence on the genesis of these stories. The connection between astral bodies and religion continued in Greek myths surrounding the constellation. Scorpius was thought to be a giant scorpion, sent to Earth by the primeval mother goddess, Gaia. Myths involving Scorpius can be found in the works of several ancient authors, including Aratus and Ovid.

The legend tells that the giant and hunter Orion became confident he was the most skilled of all in the pursuit of prey; he threatened to kill every creature on Earth. This angered Gaia, who sent a giant scorpion to battle with him. The scorpion stung and killed Orion. Artemis and Leto prayed to Zeus on Orion’s behalf, and so Zeus placed the hunter up in the stars. Zeus also positioned the giant scorpion among the stars, as a memorial to him and the battle that had happened. The two combatants were located far apart from one another in the night sky, to prevent them from fighting once more. Despite this, Orion was thought to remember the sting of his scuttling adversary, causing him to flee across the night sky before Scorpio.

Thousands of years before the Greeks and Romans and in a distant hemisphere, the Australian Aboriginal people also saw the stars of Scorpius depicting a cosmic scorpion. For the Yolgnu people of east Arnhem Land, the scorpion in the stars was named Bundungu, thought to be busily gathering with his people along the banks of the Milky Way.

The celestial scorpion was known to the people of ancient Mesoamerica. Both the Aztecs of Central Mexico, and the Lowland Mayans are known to have had scorpion constellations. It is thought that these constellations may match up with the Scorpion of the zodiac, but there is of yet no clear proof. Among the Mayan people, the Scorpion and its astral associations were called ‘Sinan’(meaning ‘scorpion’). A depiction of this constellation occurs in the Paris Codex, where a scorpion is portrayed hanging from a ‘sky band,’stinging an Eclipse of the Sun symbol. It appears likely that the Mayans viewed the celestial scorpion as an eclipse-causing agent.

The identification of the constellation Scorpius with a scorpion in a variety of cultures seems remarkable, considering the different locations and historical settings involved. Considering the myths surrounding Scorpius allows for insight into the significant interplay between animal imagery, astrology and religion in the ancient world.

References:

Cloudsley-Thompson, J. L. ‘Scorpions in Mythology, Folklore and History,’ in The Biology of Scorpions, ed. Gary A. Polis (Stanford, 1990).

Deonna, W. ‘Mercure et le Scorpion,’ Latmus XVIII (1959).

Kritsky, G. and Cherry, R. Insect Mythology (San Jose, 2000).

Thompson, R. C. ‘The Reports of the Magicians & Astrologers of Nineveh and Babylon, c.2500-670 BCE. Part VI: Omens from Halos.’ www.fordham.edu.

http://www.abc.net.au/science/articles/2009/07/27/2632463.htm

 

About the author: Dr. Louise Pryke is a Research Associate at the University of Sydney. This article is drawn from research for a forthcoming book on the cultural symbolism of scorpions, for the Reaktion Press Animal Series.

 

To help you learn about the southern night sky, Sydney Observatory provides a guide to the night sky and a sky map or chart each month. This month’s guide is presented by Melissa Hulbert, Sydney Observatory’s Astronomy Programs Coordinator.

Mel takes us on a tour of the stars and constellations prominent in the February sky, including associated tales from ancient mythology. Constellations to look for this month include Orion (whose shoulder or armpit is the star, Betelgeuse), Taurus and Canis Major (featuring the brightest star in the night sky, Sirius).

We can also see the second brightest star in the night sky this month – Canopus, part of the constellation of Carina (the keel) – formerly part of the constellation of Argo Narvis, associated with the myth of Jason and the Argonauts.

For all this and also when we can see Jupiter, Saturn, Venus and Mercury this month, read the February 2015 transcript below.

SEE THE SKY CHART
We provide an embedded sky map (below – please be patient as it can take a little while for it to load) and a February 2015 night sky chart (PDF) which shows the stars, constellations and planets visible in the night sky from anywhere in Australia. To view PDF star charts you will need to download and install Adobe Acrobat Reader if it’s not on your computer already.

BUY THE BOOK
Our annual book, ‘The 2014 Australasian sky guide’ by Dr Nick Lomb has more information and star maps for months from December 2014 until December 2015 inclusive, plus information about the Sun, twilight, the Moon and tides, and a host of other fascinating astronomical information. You can purchase it ($16.95) at Sydney Observatory and Powerhouse Museum shops or other good bookshops, or online through Powerhouse Publishing (additional packing/postage costs apply).

READ THE TRANSCRIPT (after the jump)

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MoonJupiter.20150204The Moon is full today. In the evening, around 9pm, look eastwards to see the full Moon with Jupiter just below and to the left.

 

The full Moon and Jupiter are visible in the east with Gemini, the Twins, nearby. Chart made in Stellarium.

 

 

 

 

Daily cosmobite: Dark observing locations in Sydney

Published by Andrew Jacob on February 3, 2015 3 Comments

ISS.SydneyAtNight.ISS030-E-99299Light pollution is the bane of city-based astronomers. However, night time images taken from the International Space Station help identify dark sites from which to best view the sky. Let’s begin with Sydney. Melbourne, Perth and Adelaide follow. Other Australian cities have not been photographed at night.

Sydney at night as seen from the International Space Station, 22 Feb 2012. Image,cropped from ISS030-E-99299, courtesy of the Earth Science and Remote Sensing Unit, NASA Johnson Space Center.

 

 

 

 

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