Photo: Thierry Legault
Thursday, 6 January 2011
Help! Is this book available in South Africa? Where?
Has anyone seen this book (2nd Edition) in a bookshop in South Africa.
Email and let us know! (assabfn@gmail.com) or post a comment!
The book 
Finding your way around the sky is easy with this Atlas
Atlas of the Southern Night Sky – by Steve Massey and Steve Quirk
Finding your way around the sky is easy with this Atlas
This top-selling, Australian-authored and -published hardcover atlas has been specially produced for Southern Hemisphere stargazers.
Fully revised and updated with new information, images and maps, the latest edition has easy-to-follow starcharts and details of astronomical objects that are within reach of most backyard telescopes.
Beginning with a basic introduction to the night sky—what you can see, how to find your way around the sky and what to look for— Atlas of the Southern Night Sky then delves into lunar and planetary observing, with authoritative information on how best to observe these celestial targets. This comprehensive reference book will be appreciated for years to come.
- 290 full-colour pages, hardcover
- Over 100 star charts and maps (use in conjunction with the Red Light Torch included in this pack)
- Maps of the Moon and planets
- Fully illustrated with images by Australian and New Zealand amateur astronomers to give a realistic perspective on what can be seen and photographed
- List of constellations and astronomical objects visible throughout the year
- Tips and tricks
- Guide to astrophotography and image processing
Monday, 3 January 2011
Go Voyager! Go!
The most distant space probe, Voyager 1, was about 16 light-hours away from Earth as of 9 October 2010. It took that space probe 33 years to cover that distance, and will take over 18,000 years to reach one light-year at the same speed.
Voyager 1 is about to kiss the solar system goodbye.
The plucky spacecraft – one of two Voyagers launched more than 30 years ago and now bound for interstellar space – appears to have reached a region within a broad boundary between the sun's influence and interstellar space where the speed of the solar wind's outflow reaches zero, scientists report.
The region is known as the heliopause, where the solar wind – a continuous flow of charged particles that streams from the sun in all directions at roughly 1 million miles per hour – is brought to a standstill as it meets interstellar winds head-on and gets deflected sideways.
"The solar wind has turned the corner," said Ed Stone, the mission's project scientist, in a statement. The Voyager team presented its evidence at the fall meeting of the American Geophysical Union, currently under way in San Francisco.
The boundary between the sun's influence, known as the heliosphere, and interstellar space is thought to consist of four onion-like layers: the termination shock, where the solar wind grows increasingly turbulent as the sun plows through interstellar space; the heliosheath, where the wind grows turbulent and get compressed and heated; the heliopause, Voyager 1's current location, and the bow shock, the outermost region where the solar system in essence generates a wake in the tenuous gas and dust between stars.
Voyager 1 passed through the termination shock and into the heliosheath in December 2004. The craft passed into the heliopause last June, at a distance of some 10.6 billion miles from the sun. It's currently traveling at 38,000 m.p.h.
How much time remains before Voyager 1 enters interstellar space?
A research team led by University of Arizona physicist Ke Chiang Hseih has analyzed data from Voyagers 1 and 2, as well as from spacecraft closer, to suggest that the heliopause at Voyager 1's location is only about 21 astronomical units wide (give or take 6 A.U.), or roughly 21 times the distance between the Earth and sun.
The team acknowledges that its estimate represents a "very coarse cut" at taking the measure of "a very dynamic region." But if it's correct, Voyager could take as few as four years to clear the heliopause and enter the bow shock.
The estimate was published in August in Astrophysical Journal Letters.
The latest data from Voyager 1 should help refine those estimates, researchers say.
- Today Voyager1 is 16 hrs 08 mins 22 secs of light-travel time from Earth
Sunday, 2 January 2011
Catalina Sky Survey Discovers Possible Extinct Comet
Image: This image combines thirty exposures made with the Catalina Sky Survey's 60-inch telescope a few days after the initial discovery. It shows the outburst of (596) Scheila. (Image by Alex Gibbs and Steve Larson)
An asteroid discovered more than 100 years ago my not be an asteroid at all, but an extinct comet that is coming back to life, according to new observations.
The night of Dec. 11, Steve Larson, senior staff scientist with the Catalina Sky Survey, was searching for potentially hazardous asteroids when he came across what looked like a comet: a faint, wispy tail surrounding a bright, star-like core. Four images taken over the course of 30 minutes revealed the object was moving relative to the background stars.
"Its brightness of a total magnitude of 13.4 visual, which is about 900 times fainter than the faintest star you can see in a clear, dark sky, led me to suspect that it was a known comet, but I checked the comet database and got nothing," Larson said.
According to Larson, comets are thought to be a major source of Earth's water, and "extinct" comets may be useful resources for space exploration.
Further investigation revealed that the object was a known asteroid called (596) Scheila, discovered in 1906. The extraterrestrial rock is tumbling through space alongside thousands of similar objects in our solar system's main asteroid belt, roughly between the orbits of Mars and Jupiter, out of the ecliptic plane in which most planets and asteroids travel.
Catalina Sky Survey team member Alex Gibbs checked previous images in the survey's archives but found no activity until Dec. 3. At that time, the object appeared brighter and slightly diffuse.
Previous analysis of (596) Scheila's color indicated that it is composed of primitive carbonaceous material left over from the formation of the solar system and might be an extinct comet.
After the discovery was announced, the astronomical community responded by pointing many of the world's largest telescopes at the object to obtain images and spectra to determine if its tail consists of ice and gases spewing out of the body or if it is dust left behind from a collision with another asteroid. Preliminary spectra of the outburst show that the coma surrounding the asteroid is composed of dust, but more observations will be needed to understand just what is happening with (596) Scheila.
"Most asteroids are collision fragments from larger asteroids and display a range of mineral composition," Larson explained. "But a fraction are thought to be former comets whose volatile ices have been driven off by the sun. If the activity in Scheila proves to be cometary in nature, this will be only the sixth known main-belt comet, and about 100 times larger than previously identified main belt comets."
In 1998, Larson founded the Catalina Sky Survey, a NASA-supported project to discover and catalog Earth-approaching and potentially hazardous asteroids. It operates two telescopes in the Catalina Mountains and one in Australia and is currently discovering 70 percent of the world's known near-Earth objects, including one that fell in northern Sudan in 2008.
The night of Dec. 11, Steve Larson, senior staff scientist with the Catalina Sky Survey, was searching for potentially hazardous asteroids when he came across what looked like a comet: a faint, wispy tail surrounding a bright, star-like core. Four images taken over the course of 30 minutes revealed the object was moving relative to the background stars.
"Its brightness of a total magnitude of 13.4 visual, which is about 900 times fainter than the faintest star you can see in a clear, dark sky, led me to suspect that it was a known comet, but I checked the comet database and got nothing," Larson said.
According to Larson, comets are thought to be a major source of Earth's water, and "extinct" comets may be useful resources for space exploration.
Further investigation revealed that the object was a known asteroid called (596) Scheila, discovered in 1906. The extraterrestrial rock is tumbling through space alongside thousands of similar objects in our solar system's main asteroid belt, roughly between the orbits of Mars and Jupiter, out of the ecliptic plane in which most planets and asteroids travel.
Catalina Sky Survey team member Alex Gibbs checked previous images in the survey's archives but found no activity until Dec. 3. At that time, the object appeared brighter and slightly diffuse.
Previous analysis of (596) Scheila's color indicated that it is composed of primitive carbonaceous material left over from the formation of the solar system and might be an extinct comet.
After the discovery was announced, the astronomical community responded by pointing many of the world's largest telescopes at the object to obtain images and spectra to determine if its tail consists of ice and gases spewing out of the body or if it is dust left behind from a collision with another asteroid. Preliminary spectra of the outburst show that the coma surrounding the asteroid is composed of dust, but more observations will be needed to understand just what is happening with (596) Scheila.
"Most asteroids are collision fragments from larger asteroids and display a range of mineral composition," Larson explained. "But a fraction are thought to be former comets whose volatile ices have been driven off by the sun. If the activity in Scheila proves to be cometary in nature, this will be only the sixth known main-belt comet, and about 100 times larger than previously identified main belt comets."
In 1998, Larson founded the Catalina Sky Survey, a NASA-supported project to discover and catalog Earth-approaching and potentially hazardous asteroids. It operates two telescopes in the Catalina Mountains and one in Australia and is currently discovering 70 percent of the world's known near-Earth objects, including one that fell in northern Sudan in 2008.
Source:spaceREF
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