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In this issue of SpaceTides

Hello SpaceTides subscribers

500 and counting... First of all, a warm welcome to all new subscribers who subscribed at ScopeX in Johannesburg on 6 May 2006. Also new are those that subscribed at the David Malin show at Boyden on 7 May and the friendly people from Excelsior in the Free State who had an outing at the Observatory earlier in the month. You helped to push the subscriber count above 500! All time record. Thanks to all the new and existing subscribers for your continued support of SpaceTides.

Spaceport proposals in the US are coming in one after the other. Though still in an infant stage, space tourism offers a revolution in space travel - let's just hope the spaceport contractors get business before tiring of the idea!  See CNN article. (Why not build a spaceport in the Karoo here in SA?)

ASSA Bloemfontein website: the amateur astronomers of Bloemfontein had an overhaul to their website, to keep pace with new developments in web page design. See the website.

Other ASSA Centres:  Chances are that you live near one of the ASSA Centres - clubs for people interested in astronomy. Find your nearest Centre by going to SpaceTides SA Astronomy Portal and go to the ASSA Centres section.

Where to start with astronomy? There are many books in the bookshop on astronomy, but they tend to say the same thing, only in a different way. Invest in a comprehensive book (with many pictures!) and don't forget your local library...


Gerrit Penning
Editor

Total subscribers as at 19 May 2006: 508 (+52 from previous issue #42)

1. Spaceflight news from around the world

Artist image of GLAST. Credit: General Dynamics C4 Systems

Preparing GLAST for flight
Information adapted from GFSC Press Release. 17 May 2006.

A milestone orbiting observatory, the Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in 2007. Assembly of its primary instrument has been completed.

The mission brings together the astrophysics and particle physics communities.  By using the satellite, "physicists will gain valuable information about the evolution of the universe and physicists will search for signals that may even force revision of some of the basic laws of physics", as stated by the telescope's principal investigator, Peter Michelson of Stanford University.

The observatory will collect data in wavelengths much more energetic than what our eyes can see or what optical telescopes such as Hubble can detect.  Objects under investigation will include e.g. powerful particle jets emitted from black holes "and possibly the theorized collisions of dark matter particles". Not only is its primary instrument (the Large Area Telescope) about 30 times more sensitive than previous gamma-ray detectors, but it also have a much greater field of view. Watch this space...

Artist's image of Venus Express at Venus. Image credit: ESA.

Venus Express readies for Science phase...
Information adapted from ESA News. 9 May 2006.

The European Space Agency's Venus Express orbiter reached its final operational orbit on 7 May 2006 (it was launched on November 9, 2005 and arrived at Venus in April 2006).

When the probe reached the planet, it had to perform various altitude maneuvers with its engines and thrusters in order to gain its "average" operational orbit.

Its orbital range now varies between 66 000 km and 250 kilometres above Venus. It takes 24 hours for the spacecraft to make one orbit around the planet. This orbit affords the best observation points for the probe's objectives, consisting of e.g.  global observations of the atmosphere, of the surface characteristics and of the interaction of the planetary environment with the solar wind".  The science phase begins on 4 June 2006.

2. Astronomy news from around the world

Example: largest nearby dwarf, Large Magellanic Cloud. JBO

Two new Companions to our Galaxy found
Information adapted from RAS News article.  27 April 2006.

The Sloan Digital Sky Survey (SDSS-II) announced the discoveries of two new, very faint companion galaxies in the neighbourhood of the Milky Way galaxy.  The first was found in the direction of the constellation Canes Venatici about 640,000 light years away. The second, much fainter dwarf lies towards the constellation of Bootes.

This brings the total of dwarf galaxies near our Milky Way galaxy to 14 (the most well known are the Large and Small Magellanic Clouds - both visible even with the naked eye in the southern skies - the LMC is pictured at left).   Theory of galaxy formation predicts that hundreds of clumps of "cold dark matter" should be orbiting the Milky Way and each one might be massive enough to host a visible dwarf galaxy. 

The Milky Way, M31 (Andromeda galaxy) and M33 (Pinwheel) are the largest members of the Local Group of galaxies. M31 and M33 also have various dwarf galaxies in its close vicinity.  Read more about the Local Group at SEDS. 

Photo of NGC3190. Credit: ESO.

The 2002 Discoveries of the two Supernovas  in NGC 3190
Information obtained from ESO News Release. 11 May 2006.

The beautiful spiral galaxy NGC 3190 with its tightly wound arms and a a twisted shape lies in the constellation of Leo (the Lion). It is about 70 million light years away and forms part of a small group of galaxies called "Hickson 44".

NGC 3190 has an 'Active Galactic Nucleus' and is believed to host a supermassive black hole in its bright, compact nucleus. In 2002 a supernova (a huge exploding star) was discovered in NGC 3190 in March 2002 and shortly thereafter another one was discovered in May 2002. It is a very rare event to discover two supernovas in one galaxy in one century, left alone two in one year!

3. Interesting Space Facts

1 – Sirius (-1.4)
2 – Canopus (-0.7)
3 – Alpha Centauri (0.0)
4 – Arcturus (-0.04)
5 – Vega (0.03)
6 – Capella (0.08)
7 – Rigel (0.1)
8 – Procyon (0.12)

9 – Achernar (0.5)
10 – Agena (Beta Centauri) (0.6)
11 – Betelgeuse (0.7)
12 – Altair (0.8)
13 – Aldebaran (0.8)
14 – Acrux (0.9)
15 – Antares (1.0)
(values are approximate)

List of 6 nearest star systems to the Sun and their distance in light years.

1. Alpha Centauri star system (consists of 3 stars orbiting a central point):
   Proxima Centauri (4.2)
   Alpha 1 Centauri (4.3)
   Alpha 2 Centauri (4.3)

2. Barnard's Star - a small red dwarf (6.0)

3. Wolf 359 (CN Leonis) (7.7)

4. Lalande 21185 (8.2)

5. Luyten 726-8A and Luyten 726-8B  (UV Ceti) (8.4)

6. Sirius double star system:
Alpha Canis Majoris A (8.6) and B (8.6)

Compiled  from various sources on internet. Complete list: http://en.wikipedia.org/wiki/List_of_nearest_stars

4. Space Questions

The vast emptiness of space...

What do you find between the stars in the vast emptiness of space?

Well, emptiness. Virtually a vacuum! The space between stars consists of almost nothing. Lone hydrogen atoms do float around, but at the average density of about 1 atom per cubic centimeter. It can even be as few as 0.1 atom per cubic centimeter! 

More at http://hypertextbook.com/facts/2000/DaWeiCai.shtml

Do all stars become black holes?

No. Only so-called "massive" stars can become black holes. Our star, the Sun, is not massive enough - in 4 to 5 billion years it will explode after it ran out of its nuclear fuel and form a white dwarf star located within a cloud of gas called a planetary nebula. Stars with a mass of over 10 times the mass of the Sun will explode as supernovaes and might eventually become black holes. Black holes are the highly compressed "remnants" of these massive stars and is packed with so much matter that it creates a huge gravitational pull, attracting anything within a certain distance.

Image: Digital Blasphemy.

5. Sky Observation Log

This issue's sky watching log is replaced by a piece on "sky watching tips!"

>From ASSA Bloemfontein's night sky course for beginners.

In addition to a binocular or telescope, you might also need the following while doing night sky observations:

Red filtered flashlight - Without a red-filtered flashlight, your eyes will never be able to work in a dark adapted environment – essential for effective observations. Simply put iced paper in front of your ordinary flashlight. Try to buy rechargeable batteries and a charger, it will save you lots of money and trouble!

Star charts / sky map - Without the right kind of star charts, you will quickly loose interest in observations and may even become frustrated. Books in the shops frequently have star charts, but they are not always detailed enough or customized for your location. Good star charts can be found in software programs like Skymap, Starry Night and The Sky or the free Cartes du Ciel. 

Pencil & Notebook, Drawing sheet and Report log - Equipment necessary when you start logging your observations or when you start drawing / photographing objects and report on its characteristics.

Physical Environment, comfort and practicality - Observing deep sky objects is NOT for the faint hearted. It takes effort, time and dedication. So, make sure your physical environment is as acceptable as possible. Dress for cold: cover your head, neck, nose & ears and wear a jacket and appropriate trousers (jeans-only are not the best of insulators against cold). Use a comfortable chair when sitting.

Be sure to have ALL your equipment within reach and at the ready. Check everything before going outside. And have some snacks! (Image credit: Jacques van Delft) More info on Deep Sky on the ASSA Bloemfontein website.

6. Amateur Astronomers' Corner

Can you find the coordinates of Rigel by looking at the map above? The R.A. lines run bottom-top and the declination lines run left-right. What do you think is the coordinates of Betelgeuse? Image credit: Skymap

Right Ascension and Declination

What does it mean if an object (e.g. the star Rigel in Orion) is located in the sky on the following coordinates:
RA: 5 hours, 14.7 minutes Dec: minus 8 degrees and 11 minutes (-8°, 11’)? "RA and Dec" is a coordinate system you will find on star charts. Imaginary lines in the sky:

Right Ascension work like a clock: the grid is divided into 24 celestial lines, equal to the 24 hours on a clock. It starts at 0 hours (or "24") and ends again at 0 hours. It is the celestial equivalent of the longitude lines on Earth, but measured in hours and not degrees. The 24 hours equal 360 degrees though and each hour is equal to 15 degrees.  So, how far would an object have travelled in the sky in 1 hour's time? Yes, 15 degrees (360/24).

One R.A. hour is divided into 60 minutes, which in turn, is divided into 60 seconds. The zero line of R.A. passes through the constellation of Pisces and is measured eastwards until you reach 23 hours and 59 minutes. One minute later, you are back at the zero line! Remember it as follows: when you stand facing north, the R.A. lines "ascend at your right" - they rise "parallel" with the meridian from east to west.

Declination is just like latitude: it is divided into lines from -90° to 0° and then to +90°.  With Dec, the “minus” means that you are south of the celestial equator. The “plus” means north. Where in the sky would you expect a star with declination -80 deg? Far south, near the south celestial pole, only visible to those in the southern hemisphere.  Each degree is divided into 60 minutes and each minute is divided into 60 seconds.

7. Astronomy & Science in Southern Africa

MTN ScienCentre at Canal Walk Century City in Cape Town
This interactive science centre offers edutaining fun while you learn about scientific discoveries and technological innovations. There's over 280 displays as well as an auditorium, camera obscura, computer rooms, laboratories, and exhibition hall. Entertainment for kids of all ages. Information from its website.  Visit the website.

8. Astronomy Events in the City of Bloemfontein

Boyden Observatory:  www.uovs.ac.za/boyden
One of the most publicly accessible observatories of its kind on the continent, also housing SA's third largest telescope.  To arrange group visits to the Observatory, phone Dawie van Jaarsveldt at +27 +51 - 401 2561.

Boyden open-evening on Saturday, 20 May 2006: do you want to know how it is to live in space? Have you ever thought of becoming an astronaut? Learn more about the highlights of space exploration and decide for yourself whether you should have rather become an astronaut...  Booking must take place by phoning  051-401 2322.  R30 per vehicle. 18h00 for 18h30. Telescope and night sky viewing, weather permitting.  Great friends & family outing.
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The Friends of Boyden:  www.assabfn.co.za/friendsofboyden

A public interest group for Boyden Observatory and for people interested in joining the astronomical community of Bloemfontein, but not necessarily make astronomy their hobby. Contact Braam van Zyl at 051-436 7555 (h). Anyone can become a member.
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ASSA Bloemfontein Centre:  www.assabfn.co.za

Affiliated with the Astronomical Society of Southern Africa, the Bloemfontein Centre of ASSA is an active organisation of amateur astronomers meeting on a regular basis to discuss and practice astronomy as hobby. Activities include solar-, lunar-, deep sky- and comet & meteor observations, as well as historical research, telescope making, tours and away-weekends under dark skies. Send an e-mail to mail@assabfn.co.za or visit the website.

News: The website of ASSA Bloemfontein Centre has had a total overhaul: go to www.assabfn.co.za.

9. Photo Sense

Hannes Pieterse captured this impressive photo of an immense cloud from Boyden Observatory in the Free State in February 2005.  It looks like a nuclear explosion! You don't often see this type of cloud in such great proportions from such an excellent vantage point. Shutter speed: 1/500th sec. F/4, ISO 100.  

10. Web Links

Spacewallpapers.net  - a site with an array of astronomical pictures, well worth the browse. http://www.spacewallpapers.net

International Space Station as it currently looks - must-see image by the STS 114 mission on APOD, link sent in by Neels Raath of ASSA Bloemfontein. http://antwrp.gsfc.nasa.gov/apod/ap060516.html

Goddard Space Flight Centre - A space technology fan's dream site.
http://www.nasa.gov/centers/goddard/home/index.html

Sloan Digital Sky Survey - one of the most ambitious sky mapping projects ever - http://www.sdss.org/

NASA's Solar System Exploration - what a pleasing "site" for the eyes! Excellent site with information about the solar system. Great for school projects. http://solarsystem.nasa.gov/planets/index.cfm