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In this issue of SpaceTides

Dear SpaceTides Subscribers

The first month of 2007 has come and gone. Anyone in need of a vacation already?

Comet craze flooded South Africa during January. I hope you all saw the Great Comet of 2007, named comet C/2006 P1 McNaught. If you haven't yet, there is still chance to see it through binoculars in the south-west during the evenings.

Much interest in astronomy has been generated through the comet. If you want to find out more about this fascinating subject, why not pay a visit to your local astronomy club? See a list of clubs in SA, or reply to this email with any questions.

[Astronomy Course for beginners].  As jy in of naby Bloemfontein bly is jy welkom om 'n kursus in "Sterrekunde vir Beginners" by te woon op 24 Februarie 2007, by Boyden Sterrewag. Dit word aangebied deur ASSA Bloemfonteintak. Jy hoef niks van sterrekunde te weet nie, solank jy net 'n belangstelling daarin het! Vind meer inligting onderaan.

SpaceTides is giving away a 2007 Sky Guide valued at R60 in a competition during this issue. All you need to do is answer the question "What is the name of the suspected supermassive black hole at the centre of our galaxy?". You'll find the answer in this issue. Closing date: 15 February 2007. Open to anyone. Correct answers will go into a lucky draw. Simply reply to this email with the answer.

Enjoy this issue of SpaceTides,

Gerrit Penning
Editor

Total subscribers as at 1 February 2007: 764 (+43 from previous issue #50)

1. Spaceflight news from around the world

Cut-away diagram of Hubble. Credit: NASA. Download larger image.

Hubble's dominating observing instrument fails
Adapted from HubbleSite.org, 29 January 2007. Full article.

On 27 January 2007, the Hubble Space Telescope went into a self-protective hibernation called “safe mode.”  A pressure sensor located in the section of the telescope that houses the science instruments had detected a rise in pressure. At the same time, an electrical fuse blew in the ACS, probably as the result of a short circuit.

The ACS has met its expected lifespan of 5 years, but all hope is not lost yet. If it cannot be turned back on, it can still be repaired in 2008 during the next Hubble repair mission when Shuttle crew will perform a comprehensive upgrade. It is hoped that the 2008 mission will extend Hubble's life into 2013 or even further.

Hubble still has significant science capabilities. There are various other instruments and cameras that still works perfectly fine!

Images by Hubble: http://hubblesite.org/

Artist's rendering of the New Horizons Probe flying by Jupiter. JHUAPL/SwRI

New Horizon's Pluto probe approaches Jupiter
Adapted from a JPL news release dated 23 January 2007. Full article.

After almost a year in space, the first probe to go to the dwarf planet Pluto has approached Jupiter. It still has 4 billion kilometers to go, a distance taking 8 and a half years...

The probe has already started measuring the particle environment upstream of Jupiter, looking for the first signs of the giant planet's magnetospheric influence. At the same time,  imagers are already training themselves on Jupiter, assessing its meteorological state and using its moons for both optical navigation practice and calibration targets.

The probe will get a gravity assist from Jupiter, swinging it into the outer solar system on its long voyage to Pluto and the Kuiper Belt. New Horizon's homepage: http://pluto.jhuapl.edu/

Our Sun as seen by the STEREO Ahead observatory (4 Dec 2006).

STEREO Observatories taking 3D images of the Sun
From a NASA news release dated 20 December 2006. Full article.

NASA's twin Solar Terrestrial Relations Observatories (STEREO) have sent back their first images of the sun and with them a view into the sun's mounting activity.

The probes' ultimate goal is seeing solar flares and coronal mass ejections (CMEs) in 3-D to better understand their origin, evolution and determine whether or not these outbursts are a threat to Earth.  When directed at Earth, CMEs can produce spectacular aurora and disrupt satellites, radio communications and power systems. Energetic particles associated with these solar eruptions permeate the entire solar system and may be hazardous to spacecraft and astronauts.

STEREO consists of two space-based observatories - one ahead of Earth in its orbit, the other trailing behind. With these two "perspectives", astronomers will be able to see the structure and evolution of solar storms as they blast from the Sun and move out through space.
Image from STEREO homepage: http://stereo.gsfc.nasa.gov/

2. Astronomy news from around the world

Evidence for a light echo generated by the Milky Way's supermassive black hole, a.k.a. "Sagittarius A*".

Chandra sees light echo from our galaxy's central black hole
From the Chandra website, news release dated 10 January 2007. Full article.

There's a supermassive black hole at the centre of our galaxy and it has a hungry appetite. It is called Sagittarius A* [yes, with the asterisk].  Astronomers believe a mass equivalent to the planet Mercury was devoured by the black hole about 50 years "earlier", causing an X-ray outburst which then reflects off gas clouds near Sagittarius A*.

The image shows a Chandra view of the middle of the Milky Way, with Sagittarius A* labeled. Clear changes in the shapes and brightness of the gas clouds were seen between 3 different observations in 2002, 2004 and 2005. This behavior agrees with theoretical predictions for a light echo produced by Sagittarius A* and helps rule out other interpretations.  The clouds of gas featured in the image are glowing by a process called fluorescence. Iron in these clouds has been bombarded either by X-rays from a source that had an outburst in the past or by very energetic electrons. The electrons or photons hit the iron atoms, knocking out electrons close to the nucleus, causing electrons further out to fill the hole, emitting X-rays in the process. Chandra homepage: http://chandra.harvard.edu/

3. Interesting Space Facts

Small Solar System Bodies (SSSBs)

The knowledge that we gained of the solar system way back in school is somewhat outdated. Mankind's perspective of the size and scope of the solar system has widened immensely since those "early days" and it will benefit you greatly to get up to speed with what's happening in your local neighbourhood in space...  For instance, these days children are also taught about "Small Solar System Bodies"... The solar system basically consists of:

1) The Sun, 2) The 8 planets, 3) The dwarf planets (of which Pluto is now one)
4) Small Solar System Bodies, 5) The moons of the planets

SSSBs:
- The term "Small Solar System Body", or SSSB, was only defined in August 2006 by the Internaional Astronomical Union.

- SSSBs consist of 1) the Asteroids between Mars and Jupiter, 2) the Centaurs and Neptune Trojan asteroids, 3) the Trans-Neptunian Objects (except for dwarf planets such as Pluto and Eris), and 4) comets. Trans-Neptunian Objects are mostly asteroids. Some are large and round enough to serve the criteria of "dwarf planet". These objects are divided into the regions of the Kuiperbelt, the Scattered Disk and the mysterious Oort Cloud.

Image at left: SSSB asteroids Mathilda (bottom, 56 km across) and Eros (top, 33 km long), on the same scale, both photographed by the NEAR Shoemaker satellite.   JHU/APL/NASA/JPL
More about the "New Solar System": http://en.wikipedia.org/wiki/Solar_system

4. The Solar System

Size comparison between Jupiter and Earth. Credit: NASA

Giant Planet Jupiter
Jupiter is the biggest planet in our solar system. Unlike rocky Earth, Jupiter consists almost entirely of gas, made up of mainly hydrogen. Theory states that Jupiter’s core consists of liquid metallic hydrogen (under extreme pressure) as well as rock. Even this rock might take on a liquid form.  The planet has an incredibly strong and large magnetosphere (14 times that of the Earth's), resulting in immense and dangerous radiation levels.

The stripes that can be seen on its surface are clouds moved by winds.  Giant storms can erupt on Jupiter. The Great Red Spot on Jupiter is a storm system which has been raging for hundreds of years. Jupiter also has a very faint ring system.

When Galileo Galilei aimed his telescope at Jupiter in 1609, he saw something that changed our understanding of the universe forever. What he saw was a mini solar system! Even when you look at Jupiter through a small telescope you can easily see its four biggest moons. Suddenly the notion that the Earth might NOT be at the centre of the Universe seemed all the more plausible...  

5. Sky Observation Log

Why a picture of clouds? Well, if you live inland, this is mostly what you will see in February!

Planets - February 2007
Mercury is visible in the evenings until the 17th before it's too near to the Sun for observation. Venus is acting as the wrongly called "evening star", visible after sunset in the west for the whole month. Mars rises before sunrise in the morning skies to the east. Jupiter rises after midnight and is visible throughout the morning in the east. Saturn can now be seen all night (finally! it's back!) in the north-east. Uranus shines faintly at magnitude 5.9, meaning that you will have to use a binocular if you know where it is or a binocular/telescope and finder chart if you don't! Neptune is too close to the Sun at the moment for observation. Dwarf planet Pluto is out there somewhere, but appartenly has no hard feelings. You're still in our hearts little one.

Have you visited Earth lately? I heard that their planet's magnetic field is overdue for a flip. Better watch your step!

Stars & Constellations - February 2007
'tis the season for some starry fun under hot summer skies...
When it's winter, people use the cold as an excuse not to go out star watching. In other words, now is the time to do just that! (not the excuse thing, the going outside thing!)  Without complicating your life with instrumentation, use your eyes to learn the names of the brightest stars and the most prominent constellations.

Almost above your head in February's evenings you will find Orion the Hunter. Did you know that the Orion Molecular Cloud Complex envelopes most of the constellation? You cannot see the complex, but it is hundreds of light years across. Some parts of the cloud can be observed with a binocular and telescope, while one small part, the Orion Nebula (M42), can be seen looking like a star. M42 is the central "star" of the sword of Orion, consisting in reality of a huge cloud of hydrogen gas 1,500 light years away.

Other night sky events - February 2007
Full Moon: 2 February 2007
New Moon: 17 February 2007
On 3 February at 21h00, look north-east at the Moon and you will see the planet Saturn located to its right very close by!

Consult 2007's Sky Guide Africa South handbook for detailed listings of night sky events.

6. Observatories of the World

The LBT dome. Credit: R. Pogge

The Large Binocular Telescope in Arizona, USA

The Large Binocular Telescope (LBT) is situated on Mount Graham in the Pinaleno Mountains of Arizona in the USA and forms part of the Mount Graham International Observatory. In 2006 the telescope was still under construction, but partly operational. When completed it will be the world's highest resolution and most technologically advanced optical telescope, creating images in the near-infrared which will be 10 times sharper than images from the Hubble Space Telescope. It will utilize active and adaptive optics.

Why is it called "binocular"? The telescope consists of two 8.4-meter mirrors mounted on the same base. The light collecting area will equal an 11.8-meter circular aperture.

LBT Homepage: http://medusa.as.arizona.edu/lbto/

7. Photo Sense

The above photo by Hannes appeared on Spaceweather.com and was the
photo of the week on Sky & Telescope's website.

More information and photos of comet McNaught can be found on the ASSA website.

8. Astronomy events in Bloemfontein

Datum: Saterdag, 24 Februarie 2007
Tyd: 13h30 vir 14h00, tot 21h30
Plek: Boyden Sterrewag op Harvard koppie langs Maselspoort, Bloemfontein
Aangebied deur: Die Sterrekunde Vereniging van Bloemfontein

Vir wie: Enige iemand wat 'n belangstelling het in sterrekunde, of jy iets weet daarvan of nie! Alhoewel die kursus primêr gemik is op volwassenes, sal hoërskoolkinders ook baat vind daarby.
Wat om te bring: Verkyker en digitale kamera (as jy het), verversings vir aandete. Stewige driepoot as jy wel ‘n kamera saambring.
Koste: R60 per persoon, wat insluit die kursusmateriaal, 'n sterrekunde CD, sterkaarte en 'n handige planisfeer.

Volledige inligting en kursus inhoud: http://www.assabfn.co.za/resource/course.htm
Die kursus het 'n praktiese inslag en handel veral oor naglugwaarnemings.

Besprekings: Stuur 'n e-pos na ASSA Bloemfontein by mail@assabfn.co.za of skakel Gerrit by 084 429 9080. 'n Beperkte hoeveelheid plekke is beskikbaar.

Vriende van Boyden vergaderings en Boyden Ope-aande vir die eerste kwartaal
Friends of Boyden and Boyden Open Evenings during the first quarter:
http://www.assabfn.co.za/friendsofboyden/

Die Sterrekunde Vereniging van Bloemfontein, geaffilieer by ASSA, is oop vir enige belangstellende. Webblad met kalender vir die jaar: http://www.assabfn.co.za/

9. Web links

Southern African websites:
- Comet pictures by Mauritz Geyser: http://www.etacarina.co.za/
- Cape Centre of ASSA has a new website: http://assa.saao.ac.za/capecentre
- Astronomical Society of Southern Africa, February 2007 updates: http://assa.saao.ac.za
- IOL Science News: http://www.int.iol.co.za/index.php?set_id=1&click_id=31
- Kobus Botha weather satellite photos: http://www.weatherphotos.co.za/main.html

International websites:
- Ask an Astronomer at Cornell University (quite interesting!): http://curious.astro.cornell.edu/index.php
- NASA Spaceflight.com: http://www.nasaspaceflight.com/
- Teach yourself advanced astronomy concepts at SDSS: http://cas.sdss.org/dr5/en/proj/advanced/