Cloudy Nights

Newsletter of the Harare Centre of the

Astronomical Society of Southern Africa

Vol 8 Issue 1

 

DIARY

 

Monthly Functions

Due to the current fuel shortage, the July function has been cancelled.

 

Future functions – normally on the last Wednesday of every month except December when there is no function for obvious reasons.

 

Major Annual Meteor Showers – peak activity till end of Year

 

Perseids   August 12-3, 80 meteors per hour

Orionids: October 20-22, 25 meteors per hour

Taurids: November 4, 10 meteors per hour

Leonids: November 17-18, 10 meteors per hour

Geminids: December 13-14, 100 meteors per hour

 

Oops!

 

My sincere apologies for forgetting to send out the March issue of Cloudy Nights – the one I never put together. I guess that’s what happens when you are extremely busy at work and nobody gives you a reminder!   Therefore this is a bumper issue which covers the period from January till present. Once again I thank Sally, our Secretary/Treasurer for her huge contribution in writing up the Monthly Functions. Thanks Sal!

 

Would anybody like to take over the task of knocking up Cloudy Nights on a regular quarterly basis?  

 

2005 Eclipses:

 

For the rest of the year, there will be one solar eclipse and one lunar eclipse:

2005 Oct 03: Annular Solar Eclipse

2005 Oct 17: Partial Lunar Eclipse

The lunar eclipses will not be visible from Zimbabwe.

 

 

 

2005 Oct 03: Annular Solar Eclipse

The second solar eclipse of 2005 is confined to the Eastern Hemisphere. The track of the annular eclipse crosses the Iberian Peninsula and stretches across the African continent. Europe, Western Asia, the Middle East, India and most of Africa will fall within the Moon's penumbral shadow. 

Harare will see a maximum of 40% partial eclipse peaking at about 13:45 pm.  

The above information sourced from the web site: MrEclipse.com  

 

Monthly Functions:

 

January 2005: 

 

Our first meeting of the year was on Australia Day (Jan 26th).

 

As usual Dave Pringle-Wood gave us the sky-lights for the current month and the month ahead. The last comet had all but disappeared by then but had been regularly observed during January and Dave reported that both tails had been visible through the telescope. The Southern African Sky Guide for 2005 was now available, highly recommended to anyone with R55 to spare. Dave reminded us that it was part of his mandate as Chairman to encourage us all to get observing. An especially good night for star-gazing would be 7th February as a meteor shower was due then in the region of Alpha Centauri from 10:00pm – 3:00am. The other big news item was that Voyager II had landed on Titan as planned and we could look forward to about 350 pictures in due course.

 

Tony Alegria did the What’s Up, pointing out Jupiter currently in the Virgo constellation, Saturn next to Pollux and introduced (most of) us to Monoceros, the unicorn.

 

Mike Begbie then talked to us on binoculars for astronomy, particularly aimed at first-time buyers and what to check if you were considering buying a second hand pair. For astronomy it is important to have a big aperture so opt for 7 x 50 or 10 x 50 (not the more common 8 x 20) and preferably, a centre-focus system. Mike’s checks included:

  • look through the binos backwards - to check for mistiness, a bad sign
  • twist the barrels - should be no play
  • look through backwards for a blue or green tinge - a good sign
  • find the coating description - “multi-coated” is better than “fully-coated”
  • look through (normally) at a telephone pole – to check for mis-alignment
  • look through backwards at the end shape –squarish is bad, circles are good

With binoculars costing anything from 1 million (for dubious second-hand ones) to 30 million (for state of the art new ones) it was a talk worthy of close attention.

 

The main event was an excellent video, “The Unfolding Universe”. This took us traveling through time from a brilliant mock-up of the Big Bang (approx 15 billion years ago) through star and galaxy formation, the fusion of matter into heavy elements, then slowed up into Here We Are, (third rock from the Sun.) Moving on again, we have to accept the eventual red-giant fate of our sun and its gobbling of the near planets (including Earth.)  (Remember, Man, that thou art Dust … with a big D.)

But that’s not all. The ultimate spectacle awaits those lucky astronomers who are suitably placed in 7 million years time for then our Milky Way galaxy will collide with the nearby Andromeda galaxy!

If ever there was a video that completely lifts your thinking from mundane issues, The Unfolding Universe is it.

 

                                                                                      

February 2005

 

Your roving reporter slid in late to the February meeting and so must apologize for being unable to provide any feedback on the curtain-raiser talk on Observing by Mike Begbie. Several fascinating pictures from the recent Titan landing were on display on the front desk.

 

Francis Podmore gave a slide show of his Favorite Things from his comprehensive collection as the main event. Francis began with spectacular phenomena that can be seen from Earth without instruments at certain times and places, eg the Aurora Borealis (Northern Lights). Stepping out into the solar system, the next slides showed the diversity of our neighbouring planets, some taken during space missions. Looking light years out into and beyond our own galaxy, Hubble has zoomed in on many deep sky objects. There were several slides of wonderfully coloured gas nebulae lit up by their neighbouring stars in the Milky Way and finally some swirling galaxies. Thank you, Francis, we were well entertained and agree with you that there is a spiritual dimension to star-gazing.

 

March 2005

 

The March monthly function was cancelled as a safety precaution due to the Parliamentary Elections being held the next day.

 

 

 April 2005

 

First, Tony Alegria told us What’s Up using current star charts. This is always appreciated by the many amateurs amongst us who are keen to increase our knowledge of the constellations. We would not otherwise know that a particular constellation is currently hosting a planet or where to look for good binocular objects.

 

The topic chosen by Dave Pringle-Wood for the What Is talk was Bode’s Law.

 

In 1776 one J.D.Titius noticed that a mathematical “formula” could be used to give the distances of the known planets from the sun. (At that time the known planets ended with Saturn.) Titius made a sequence with zero, then 3, and all subsequent elements = double the last one. Then he added 4 to each number in the sequence, (conveniently turning the third element into 10) and finally he divided each element by 10. So the first seven elements in the sequence were 0.4, 0.7, 1.0, 1.6, 2.8, 5.2 and 10. Ignoring for now the 2.8 element, these are indeed the distances (in au) of the first 6 planets from the sun to 2 sig figs. Sadly for Titius, he was a better number-cruncher than a businessman and it was J.E.Bode who published the “Law” and named it. After himself!

The next 2 elements in Bode’s sequence work out as 19.6 and 38.8 and a little later (1781) a new planet (Uranus) was discovered at 19.18au from the sun, intriguingly close to the 19.6 slot. The search was now on for the “missing” planet at 2.8au and in 1801 Ceres (a large asteroid) was found at that distance. It took many more years to discover that a whole asteroid belt existed around Ceres and for astronomers to agree that the belt constituted an alternative to a planet at 2.8au. But the renewed acceptance of the sequence did not last long. In 1846 the next real planet (Neptune) was discovered and at a distance of 30au it rather blew Bode’s Law out of the water. Bode’s Law is now deemed nothing more than an interesting coincidence, a warning perhaps of the tricks that numbers can play on you. Thanks Dave, it was satisfying to hear that the plagiarist came a bit short in the end.

 

The April meeting concluded with a short video.

 

 

May 2005

 

The May monthly function fell on the 25th of the month which was a public holiday - Africa Day.  Thus the function was postponed for one week and held on the 1St June when a viewing evening was enjoyed by a smallish gathering.  This was probably fortunate as three committee members (and their telescopes) were not present and as a result only one telescope was available. Thanks to our Chairman (Dave Pringle-Wood) for bringing and driving his telescope for the viewing session.   Before the viewing session began, Tony Alegria used star charts to indicate the various heavenly bodies which were to be observed, these being planets (Jupiter & Saturn), double stars, open and globular clusters as well as nebulae.  The sports fields of Prince Edward School suffer from light pollution and do not lend themselves to telescopes viewing dim objects such as galaxies!

 

 

June 2005

 

Tony Alegria presented the regular “What’s up” and concentrated on the smallest constellation, the well-known Crux, or Southern Cross as well as Centaurus – the man-horse. He will expect intelligent answers at the next meeting about where to find double stars, globular clusters etc in that area of the sky!

 

The “What Is” talk was given by Dave Pringle-Wood who told us about the much-anticipated bombardment of a comet by NASA on 4th July. The impact was expected to brighten up the comet by a few magnitudes. 

 

Dave’s talk was a good fore-runner to the main event as this was a video on “impacts and accuracy”. Evidence abounds that the planets in our solar system are whacked by objects from outer space from time to time. Just looking at the moon is proof enough. Recently professional astronomers predicted that Jupiter was going to be hit by a comet. No one was surprised that events proved them right but it was still impressive that the pinpointed time and position was spot on. The ability we now have to forecast such events and film them is phenomenal and some excellent footage of the Jupiter collision was the result. The video also showed other feats of accuracy such as landing a probe on an asteroid and went into the patient scanning work done by a team of scientists who were convinced that the age of the dinosaurs was ended by a cosmic impact. Eventually a massive undersea crater was detected off the coast of Mexico and it would seem to prove them right.

So practicing the bombardment of distant comets has merit and could in fact be an earth-saving skill.

 

 

 

 

The Millennium Run

 

Scientists go back to the very beginning

By Nic Fleming, Science Correspondent

(Filed: 02/06/2005)

 

Scientists unveiled yesterday the most detailed model yet produced of the development of the universe.

 

The Millennium Run simulation shows how galaxies and quasars are thought to have evolved following the Big Bang 13.7 billion years ago.

 

  An image was produced by simulation showing how the universe evolved after the Big Bang

 

It is the result of 500,000,000,000,000,000 (500,000 trillion) calculations made by one of the biggest supercomputers in Europe after it was given information on the current composition of the universe, the microwave radiation left over after the Big Bang and the laws of physics.

 

The ultra-high-resolution simulation was created by tracking 10 billion particles of dark matter, the mysterious and invisible material that spreads out across the universe in gigantic strands, through the evolution process.

 

They focused on the evolution of a cubic region measuring two billion light years on each side - about 0.5 per cent of the universe - from just a few hundred million years after the Big Bang until the present.

 

Prof Carlos Frenk at the Institute of Computational Cosmology, University of Durham, and head of the project in Britain, said last night: "This is the first fully realistic attempt to model the entire evolution of the cosmos in detail.

 

"Because of the amazing computational power we had at our disposal we have been able to model everything right down to dwarf galaxies, whereas previous attempts could only give us fuzzy pictures of larger clusters of galaxies.

 

"For the first time we can peer into the inner workings of the universe and understand cosmic evolution in its entirety."

 

The new simulation, details of which are published in the magazine Nature today, was created by the Virgo consortium, a team of scientists from Britain, Germany, Canada and America led by Dr Volker Springel, of the Max Planck Institute of  Astrophysics, near Munich. The scientists used the Max Planck Society's Supercomputing Centre in Garching, Germany, to make the calculations.

 

It is being hailed by cosmologists as the first accurate model of the universe because it has correctly predicted information that has since been observed, such as the fact that in the cubic region chosen there should be about 17.5 dwarf galaxies, two million normal galaxies similar in scale to our Milky Way, and half a million giant galaxies.

 

Simon White, of the Max Planck Institute, said: "New observational campaigns are providing us with information of  unprecedented precision about the properties of galaxies, black holes and the large-scale structure of our universe.

 

"Our ability to predict the consequences of our theories must reach a matching level of precision if we are to use these surveys effectively to learn about the origin and nature of our world, and the Millennium Run is a unique

 

 

 

 

 

Our Planets etc. as seen from Harare on 1st August 2005

 

Mercury in Cancer:   mag  3.8,  rises 6.41 am,  sets  6:14 pm,  Illum 3.5%

 

Venus in Leo:  mag  -3.9,  rises 8:17 am,   sets 8:00 pm,   Illum 83.3.7%

 

Mars in Pisces: mag  -0.5,  rises 11:30 pm,  sets  11:10 am,    Illum 84.2%

 

Jupiter in Virgo: mag -1.8,   rises  09.59 am,  sets   10:13 pm,  Illum 99.3%

 

Saturn in Cancer:  mag  1.0,  rises  5.58 am,   sets  5.08 pm,  Illum 100%

 

Uranus in Aquarius:  mag 5.7,  rises 7:48 pm,  sets  8:17 am ,   Illum 100%

 

Neptune in Capricornus: mag  7.8,  rises 6.06 pm,  sets  6:56 am,  Illum 100%

 

Pluto in Serpens: mag  13.8,  rises  2.19 pm,  sets 3.06 am,    Illum 100%

 

Sun in Cancer:  mag  -26.8,  rises 6:22 am,  sets  5:42 pm

 

Moon in Taurus:  mag  -10.3,  rises 3:31 am,  sets  2:34  pm,   Illum 11.3% - Waning Crescent

 

 The above planet’s positions and brightness do not change dramatically except for the inner planets which take far less time to circle the Sun – things don’t change much in a week!

 

 

Points of interest concerning the planets:

 

A new addition to the normal information is the amount of illumination (Illum) based on how much surface area is visible to us as a percentage. This percentage goes hand in hand with the magnitude (mag) of the planet - the more surface to be seen, the brighter the planet appears to be also bearing in mind where it is in relation to us.  Venus and Mercury are both evening “Stars”.

 

 

Our Web Site

 

Our Internet web site: http://www.geocities.com/zimastro will be updated on a regular basis to advertise our monthly functions and will include the latest Cloudy Nights.

 

 

Your 2004/5 Committee

 

Chairman:        Dave Pringle-Wood   741064 H  073-2527/9 B   091 909 701 

                            Email: "David Pringle-Wood" <dpwood@mweb.co.zw>

 

V/Chairman:     Tony Alegria  490375 H  883823 B   Email:  talegria@cabs.co.zw

                      

Secretary/Treasurer:    Sally Britten   497981 H  883823 B   Email: sbritten@cabs.co.zw

 

Membership Secretary and Curator of Instruments:   Gil Rausch  744967 H 011 401 076

 Email:” Gil Rausch “ <gil@zim.co.zw>

 

Librarian:         Jim Black  481064 H  023 832 509   Email: jblack@zambezi.net

 

Member:          John Mussell     339311 H   091 248 026  Email: johnmus@mango.zw  

 

Member:          Mike Begbie       331478   Email: "Mike Begbie" <songbird@mweb.co.zw>

 

 

ASSA Council Rep: Mike Begbie

 

 

 

Harare Centre of the Astronomical Society of Southern Africa

(ASSA

Box UA 428, Union Avenue, Harare, ZIMBABWE

 

Our web site:  http://www.geocities.com/zimastro

 

Cloudy Nights

Editor: Tony Alegria