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In this issue of SpaceTides

Dear SpaceTides subscribers

Please see the "Feedback form" information below. Your comments about the SpaceTides e-zine will be much appreciated! Filling in the form will only take a minute or two. Access it at www.assabfn.co.za/spacetides/feedback.htm or ask us to send you one if you don't have internet access.

Enjoy this issue of SpaceTides,

Gerrit Penning
Editor

Total subscribers as at 8 June 2006: 528 (+20 from previous issue #43)

Feedback Form

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You are invited to air your opinion on SpaceTides. Your comments and suggestions are welcome. The form is anonymous and should help to futher improve the quality of the SpaceTides e-zine. Please visit www.assabfn.co.za/spacetides/feedback.htm.

Importance of Astronomy

Importance of Astronomy write-up on website
If someone ask you why we spend so much money on scientific/astronomical research, you might want to use some of the points given in this write-up. I promised it awhile ago in one of the previous issues.

You can access the write-up at www.assabfn.co.za/spacetides/issues/importance.htm

1. Spaceflight news from around the world

The SOHO spacecraft, artist's rendition. Credit: ESA

SOHO set to work until 2009
Information partly obtained from an ESA News Release, 24 May 2006

The Solar and Heliospheric Observatory (SOHO) was launched on 2 December 1995 and has provided scientists and unprecedented view of our closest star, the Sun. New funding will allow SOHO 's mission to be extended to December 2009.

Even though SOHO is over ten years old, it is still beaming back very important data relating to the Sun. It monitors the Sun's activity and even allows scientists to peer into its inner parts through the recording of seismic waves that ripple across the surface.

During the next two years, five new solar spacecraft will join SOHO and the rest in orbit. A whole fleet of probes will then be monitoring the Sun. Research is crucial, as scientists are only now beginning to truly understand the impact that the Sun has on Earth's components like the magnetosphere, atmosphere, climate, etc. We are fortunate that our Sun is so stable, but let's not take any risks!

Shuttle Discovery on its launch pad. Credit: NASA-KSC

Shuttle Discovery set to launch on 1 July 2006
Information from obtained from the NASA website, June 2006.

Space Shuttle Discovery's launch is targeted for July 1. The launch window extends to July 19. Mission STS-121 as it is called will pay a visit the International Space Station (ISS) and will also continue evaluating new shuttle safety improvements.

At least two spacewalks are planned during the 12-day mission, which also includes repair work to the station.   Maintenance to the ISS is also scheduled to be performed and the shuttle will deliver supplies and cargo for future station expansion.

Discovery will bring a third crew member to the station, ESA's Astronaut Thomas Reiter.  This will be the first three-person crew since the Expedition 6 crew returned to Earth on 4 May 2003.

2. Astronomy news from around the world

Artist depiction of an asteroid hitting the Earth. (OSU website)

Huge crater found under Antarctic ice shelf
Information obtained from an Ohio University News release. 1 June 2006.

Planetary scientists have found evidence of a meteor impact much larger and earlier than the one that killed the dinosaurs 65 million years ago - an impact they believe might have caused the biggest mass extinction in Earth's history.

The 483 km wide crater lies hidden more than a kilometer beneath the East Antarctic Ice Sheet.  The scientists used gravity fluctuations measured by NASA's GRACE satellites to peer beneath the surface. The measurements that reveal its existence suggest that it could date back to about 250 million years, corresponding to the time of the Permian-Triassic extinction, when almost all animal life on Earth died out.

The evidence also suggests that the impact could have begun the breakup of the Gondwana supercontinent by creating the tectonic rift that pushed Australia northward. Scientists believe that the Permian-Triassic extinction paved the way for the dinosaurs to rise to prominence.

NGC 6164-5 imaged at Gemini South. Image credit: Gemini.

A View of NGC 6164-5
Information obtained from a Gemini Observatory News Release dated 5 June 2006

This image shows the emission nebula NGC 6164-5.  It lies about 4,200 light-years away in the constellation Norma. The nebula measures about 4.2 light-years across, and contains gases ejected by the star HD 148937 at its heart. This star is 40 times more massive than the Sun, and although it is only about three to four million years of age, it is already past the middle of its life span.  The star is aging quickly, as stars this massive usually live to be only about six million years old. Its end will most likely take the form of a supernova explosion.

NGC 6164 and 6165 are visible to amateur astronomers using proper telescopes. NGC 6164-5 is a small (6’ x 3’) inverted S-shaped nebula. Its appearance in a telescope is adversely affected by the brightness of its star, 6.8-magnitude HD 148937. (The dual NGC entry refers to the nebula’s two brightest crescents, discovered by Sir John Herschel in 1834 while observing from the Cape of Good Hope in South Africa). NGC 6164 lies northwest of the central star, while NGC 6165 lies immediately southeast of it.

3. Interesting Space Facts

The Basic Types of Telescope (refractors and reflectors)

Refracting telescopes: The refractor uses a lens at the front. Light passes through the lens and is focused towards the eyepiece at the back.  They are much longer compared to reflectors of similar aperture. Illustration of how a refractor works:

Reflecting telescopes: Reflectors usually use a concave mirror at the back to collect and focus the incoming light back onto a flat secondary (diagonal) mirror. The secondary in turn, reflects the light out through an opening at the side of the main tube (in the case of a Newtonian design) or through a hole in the primary mirror (in the case of a Cassegrain) - and into the eyepiece. There are various types of reflectors, but only the Newtonian design is illustrated here:

4. Space Questions

M16, the Eagle Nebula - NASA, ESA, STScI, J. Hester and P. Scowen ( Arizona State University )

What is the Eagle Nebula?

The Eagle Nebula is a huge cloud of gas and dust. Amateur astronomers will recognise it as Messier object 16 - it is 7,000 light years away and is located in the constellation of Serpens Cauda. It is also a breeding ground for new stars, which illuminate the gas.

The Hubble Space Telescope has taken pictures of immense hydrogen and dust "pillars" in the nebula.  These pillars are slowly "evaporating" due to intense radiation from massive stars that were recently born nearby.

New stars are forming from gas that condenses within these stellar nurseries, a process that can take about one hundred million years. Source: HubbleSite FAQ.

Hierdie foto verskyn ook op die voorblad van Gideon Joubert se boek, "Die Groot Gedagte" - a boek wat ten sterkste aanbeveel word, alhoewel dit 'n tweede of selfs 'n derde keer (of meer) gelees moet word voor die moeiliker konsepte verstaanbaar raak! 'n Goeie agtergrond kennis in basiese sterrekunde voor 'n mens die boek aanpak sal ook help. M16 is sekerlik een van die mees gepaste foto's wat Gideon vir sy voorblad kon kies.

5. Sky Observation Log

Not sure where to start with the night sky? Contact SpaceTides for assistance!

Photo with 30 seconds exposure, the pointers visible at left and Crux above centre. An Astronomy Grade  green laser pointer was held steady on the star Alpha Crucis.

Planets visible - June 2006
Mercury is visible after sunset, for the whole month, fading as the days progress.
Venus is still a morning object, shining with a fierce glow in the east.
Earth is not too bad. In fact, its conditions are so close to perfect, that it can even support life! If you happen to live on this very peculiar little speck in space, try to have respect for it, for the sake of its future generations please.
Mars is situated in the evening sky in the north-west.
Jupiter (evening) shines bright in the east, moving over the meridian as the night goes by.
Saturn is close to Mars in the north-west. Don't confuse the two! Mars has a red colour.

Constellations and stars
Some of the major late-autumn constellations now visible in the evening sky include Virgo (its brightest star, Spica, is quite prominent) with its numerous galaxies, Corvus and Crater close by (the Crow and Cup) and Coma Berenices to the north with its large and beautiful star cluster visible to the naked eye. To the south are Centaurus, Crux and Musca.

Deep sky Objects
Here are a few specially selected deep sky objects suitable for observation during this time of the year. Binoculars: IC 2602, NGC 2516, NGC 3532 (open clusters) and NGC 3372 (nebula) all in Carina. If you still need to observe objects in Puppis, you only have a few weeks left early evenings! Telescopes: (8 inch & up recommended): NGC 3132 (Eight-burst planetary nebula) in Vela, NGC 5128 (Centaurus A galaxy), NGC 3766 (open cluster) in Centaurus, NGC 3293 (open cluster) in Carina. NGC 3242 (Ghost of Jupiter planetary nebula) and M83 (galaxy) both excellent objects in Hydra.

Other events
Full moon on 11 June 2006. New moon on 25 June 2006.
The Moon occults the star Antares in the early morning hours on 11 June 2006 - see section 6 below for more info.

6. Amateur Astronomers' Corner

The moon occulting Jupiter, photo by Hannes Pieterse (ASSA Bloemfontein) on 22 April 2005.

Lunar Occultations

An activity that amateur astronomers can undertake is the observation of lunar occultations. When the moon move in front of a star or planet, a total occultation takes place (the star or planet "disappears" behind the moon). Objects disappear at the eastern edge of the moon - remember that the moon moves in the opposite direction to the stars.

Stars disappear instantly while planets fade behind the moon. As the moon moves through the zodiacal zone, it sometimes occults bright stars (and naked eye planets). Lunar occultations for 2006 can be found on page 56 of ASSA's Sky Guide Africa South. 

The next major occultation is due on 11 June 2006 when the moon occults the bright red giant Antares (magnitude 1.1) in Scorpius. For Bloemfonteiners the time of disappearance is at 01:03:59 (69 degr.) and reappearance 02:23:46 (51 degr.). Remember to watch early morning 11 June and not 12 June! Set your alarm on 10 June before going to bed.

7. Astronomy & Science in Southern Africa

Cape Town Planetarium

The Planetarium is housed in the South African Museum building in Cape Town and is a "celestial theatre in the round", utilizing a Minolta star machine and multiple projectors to transport the audience through the wonders of the universe. The Planetarium's website can be found at http://www.museums.org.za/planetarium/about.html

8. Photo Sense

Mountains in the Hex River Valley in the Western Cape , South Africa , towering over the famous wineries in the area. The picture's contrast was increased to bring out the various and vivid colours. Picture taken (from a moving car!) by Gerrit Penning on 18 March 2006 with a Sony 5.1 DSC-P93A digital.

9. Web Links

1st Weather.com: a reliable source for up to date and accurate weather data in South Africa . http://www.1stweather.com/

HobbySpace - Astronomy:  HobbySpace's pages for astronomy with numerous news links and links to other websites. http://www.hobbyspace.com/Astronomy/index.html

Night Sky Observer: An on-line resource with news and numerous topics relating to Astronomy.  http://www.nightskyobserver.com/

ISS Sun-Moon transit information: Probably the best opportunity to photograph the details on the International Space Station is when it moves in front of the moon or sun. http://iss-transit.sourceforge.net/

Past Spacecraft Missions: A summary of previous missions in the solar system. http://www.nineplanets.org/spacecraft.html

Starting with Astronomy instruments: You will never be able to see everything you want with today's commercial telescopes. Read this first!

Astronomy Software list: http://astro.nineplanets.org/astrosoftware.html