Cloudy Nights

Newsletter of the Harare Centre of the

Astronomical Society of Southern Africa

Vol 7 Issue 3

 

DIARY

 

Monthly Functions

 

January Function: Wed 26th

What is – Observing – Mike Begbie

Main Event – 2nd part of the “Race to the moon” video

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 April

 

Quadrantids: January 3-4, 100 meteors per hour

Lyrids: April 21-22, 10 meteors per hour

 

 

Oops!

 

My sincere apologies for forgetting to send out the September 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 July till present.

 

2005 Eclipses:

 

During the year 2005, there will be two solar eclipses and two lunar eclipses:

2005 Apr 08: Hybrid Solar Eclipse

2005 Apr 24: Penumbral Lunar Eclipse

2005 Oct 03: Annular Solar Eclipse

2005 Oct 17: Partial Lunar Eclipse

Both lunar eclipses are not visible from Zimbabwe.

 

 

2005 Apr 08: Hybrid Solar Eclipse

The first solar eclipse of 2005 is of an uncommon type known as either annular-total or hybrid. This is a unique class of central eclipse where some sections of the path are annular while other parts are total. The duality comes about when the vertex of the Moon's umbral shadow pierces the Earth's surface at some points, but falls short of the planet along other sections of the path. The unusual geometry is due to the curvature of the Earth's surface which brings some geographic locations into the umbra while other positions are more distant and enter the antumbral rather than umbral shadow. In most cases (like in 2005), the central path begins annular, changes to total for the middle portion of the track, and reverts back to annular towards the end of the path. However it is also possible for the central path to begin annular and end total  or vice versa. Since these events occur near the vertex of the Moon's umbral/antumbral shadows, the central path is typically quite narrow.  

This eclipse is not visible from Zimbabwe. The path of the Moon's shadow begins southeast of New Zealand and stretches across the Pacific Ocean to Panama, Columbia, and Venezuela. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes New Zealand, much of the South Pacific, South and North America.

 

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:

 

July 2004:  The AGM was held at this monthly function and was followed by a video entitled: “Edge of the Universe”.

 

AGM Chairman’s Report – Dave Pringle-Wood

 

The period July 2003 to June 2004 has provided members with a variety of astronomical events together with talks and videos hosted at our usual venue, the Harold Robinson Lecture Theater at Prince Edward school on the last Wednesday of the month (excluding December).  There has been a slight reduction in members attending the monthly functions although I wish to add that our Centre has also obtained a number of new members for which I am gratefully welcome.

 

Tony Alegria resumed the post of Vice Chairman as well as editor of our newsletter Cloudy Nights which is forwarded to members by e-mail.  He has produced three issues covering this period.

 

I would like to thank Tony Algeria for this undertaking.

 

Sally Britten completed her first year as Treasurer attending to our finances and acting as secretary at our committee meetings which were held at Gil Raush’s residence during the year.  Gil continued as Membership Secretary and Curator of Instruments.  Jim Black has attended to the library once again this past year.  John Mussel and Serena Ansley made up the remainder of the 2003/4 committee, with John working on an astronomy guide publication.

 

Also of mention, I extend my thanks to members who have delivered presentations over the past year or who have assisted in providing material for presentations such as videos or making their telescopes available for use by members at observing occasions.

 

The highlights of the year included the 4th May Total Lunar eclipse, the 8th June Venus transit event as well as observations of comets Neat Q4 as Linear T7.

 

PAST MONTHLY MEETINGS

 

 

JULY 2003

 

AGM and Chairman’s report followed by Lyn Morris’s presentation on Meteor showers.

 

AUGUST 2003

 

What’s Up:                       Tony Alegria – Mars and the constellation Aquarius.

 

Main Event:                     Francis Podmore discussed Mars and its closest approach to earth this month.

A short video on the European Space Agency mission to Mars followed by an observation of Mars through a number of member’s telescopes.

 

SEPTEMBER 2003

 

What’s Up:                       Tony Algeria – September’s Sky

 

What Is:                            Francis Podmore explained what is an Analemma.

 

Main Event:                     Pete Morris talked on the various methods of Sundial construction.

 

OCTOBER 2003

 

What’s Up:                       Tony Algeria – October’s Sky

 

What is / Main Event:     Francis Podmore delivered a talk on the topic of our Sun named “Solar Secrets”.  This was followed by a video on the same theme.

 

NOVEMBER 2003

 

What’s Up:                       David Pringle-Wood – Plutoids and Kuiper Belt objects.

 

What’s Up / Main Event:      Tony Algeria – Powerpoint presentation on constellations.

 

JANUARY 2004

 

What’s Up:                       Tony Algeria – January’s Sky

 

What Is:                            David Pringle-Wood – Astronomical events to observe during 2004.

 

Main Event:                     Video on the planets of our Solar system (Part 1).

 

FEBRUARY 2004

 

What’s Up:                       Tony Algeria – February’s Sky

 

What Is:                            David Pringle-Wood – Astronomy and Astrology.

 

Main Event:                     Video on the planets on our Solar system (Part 2).

 

MARCH 2004

 

What’s Up:                       Tony Algeria – Where to locate comet 2001 Q4 (NEAT).

 

What Is:                            David Pringle-Wood presented a talk on “Exoplanets” and methods of their discovery past, present and in the future.

 

Main Event:                     Tony Algeria with a powerpoint presentation on “Mars Missions”.

 

APRIL 2004

 

What’s Up:                       Tony Algeria – April’s Sky

 

What Is:                            David Pringle-Wood – Forthcoming 4th May Total Lunar eclipse.

 

Main Event:                     Tony Algeria – “Mars Missions” (Continued).

 

MAY 2004

 

What’s Up:                       Tony Algeria – Comets 2001 Q4 (NEAT) and 2002 T7 (LINEAR).

 

What Is:                            David Pringle-wood – Forthcoming 8th June Venus transit.

 

Main Event:                     Viewing evening.

 

JUNE 2004

 

What’s Up:                       Tony Algeria – June’s Sky.

 

Main Event:                     John Mussell presented a talk on “Measuring the Universe” which was followed by a recent BBC video on the 8th June Venus transit supplied by Francis Podmore.

 

OBSERVATIONS

 

The following astronomical observations were made in the period 31 July 2003 to 31 June 2004:

 

COMETS

 

2002 V1 (NEAT):              Begbie - 10 observations

 

2P Encke:                           Begbie - 2 observations

 

2001 Q4 (NEAT):              Begbie - 50 observations, over 30 drawings and several photographs.

 

                                          Pringle-Wood - 25 observations.

 

2002 T7 (LINEAR):           Begbie - 29 observations, 15 drawings and several photographs.

 

                                          Pringle-Wood - 14 observations.

 

2003 K4 (LINEAR):          Begbie - 5 observations so far, this comet will remain visible for several months

METEORS

 

The Perseid shower was observed by Begbie from Southern England.  Despite a Full Moon, 17 Perseids were observed in one 15-minute period, including two fireballs.

 

An outburst of the Pi Puppid shower was observed by Begbie close to the predicted time and the results reported to the International Meteor Organisation.

 

LUNAR ECLIPSE (9TH NOVEMBER 2003)

 

Begbie – 3 crater timings and photography.  Begbie rated the Danjon value as averaging L=2 for this eclipse, as opposed to L=4 for the 9th January 2001 event.

 

LUNAR ECLIPSE (4TH MAY 2004)

 

Begbie – 22 crater timings and photography.  “Averaged” Danjon Value across the Moon using 7x50 binoculars yielded L=1.8.  Derived visual magnitude at mid-totality was therefore –0.5.

 

Pringle-Wood – 14 crater timings.

 

TRANSIT OF VENUS (8TH JUNE 2004)

 

Observed by Begbie and Pringle-Wood.  All four contact times were achieved by both observers.

 

CEES MESU MEMORIAL TRUST

 

The trust continues to make arrangements for the fabrication of a 20” F6 Primary Mirror with Swayze Optical Inc, Portland, Oregon, USA.

 

THANKS

 

The Committee has worked efficiently throughout yet another trying year and I extend my thanks to its members.

 

I also extend my thanks to the headmaster of Prince Edward school, who once again has supported our activities with the free use of this venue as well as the generous teas and snacks.

 

In ending, I would like to thank all members for their continued support in attendance to our Centre’s monthly meetings.

 

CHAIRMAN - DAVID PRINGLE-WOOD

 

28 JULY 2004

 

August 2004

Whats up – Constellations, planets etc.  Whatever could be viewed at the time, weather permitting of course!

Dave Pringle-Wood  under “What is”  presented  “Basic Observational Astronomy” .  An enlightening talk on what you can or cannot see in various skies using the naked, eye, binoculars and telescope. Also a few tips on the best ways of observing.  I will add this presentation to our web page!

In the “Main event” ,  Frances Podmore used slides to give us a “Journey through Space”. Frances began with a few slides on our Sun and proceeded past each planet and  their moons eventually ending with remote galaxies. With each slide there was, more often than not , a witty explanation of the main or strange features.

 

September 2004

 

Tony Alegria gave us a short “What’s Up” using current star charts.

This was followed by “What is”  a Black Hole by Dave Pringle-Wood. Dave did this with his customary thoroughness. Listening to him it seemed not only plausible but inevitable that there are objects so dense that they “suck in” light and that one place to find them is at the centre of a galaxy.

Mike Begbie presented the “Main event”, “Basics of Astronomical Observing”. He began with some guidance on how to choose suitable binoculars, showed us a star-chart “globe” and explained the apparent motions of the sky. There are a number of simple practicalities to understand and follow when observing, eg “dark-adapt “ your eyes; use a red filter on your torch so as to maintain your pupil-dilation when referring to star charts; use peripheral vision when trying to find very faint objects. Mike explained how the magnitude of a comet or a variable star is determined: you mentally put it in its (brightness) place between two other stars with steady known magnitudes, assess the ratio and do a simple calculation. It was good to know that even rookie astronomers with modest mathematical skills can make useful contributions to the official pools of data on such objects.

 

October 2004

 

In the “What’s Up”, Tony Alegria attempted to confuse us with an upside down and laterally switched star chart … until someone spotted the dyslexic compass points! Flavour of the month was the globular cluster in Tucana – Tucanae 47.

 

I n the “What is” Dave Pringle-Wood gave us the timings and expectations for the full lunar eclipse that was occurring early the next morning. Sadly this turned out to be a non-event in Harare because of (cryptic clue) the name of this newsletter.

The “Main event”, “Comets”, was presented by Mike Begbie. One of the earliest recordings of a comet was Halley’s Comet in 1066. It was exceptionally bright that time … and totally misunderstood. Instead of people enjoying the spectacle they regarded it as a portent of disaster and were extremely nervous but at least the strange ball of fire was well documented. Comets were far more common in the dawn of time. Mike calls them “the building block debris from solar system evolution”. It is now thought that 99% of the water on our earth is the result of intense comet bombardment which occurred about three million years ago. Current thinking also credits comets with having brought the initial organic material necessary for the start of life here. Fascinating stuff.

 

November 2004

 

“What’s Up”: Tony Alegria used the current star chart to tell us how to determine which was which re: Castor and Pollux. He also showed us where to look for the Horsehead Nebula  and the M42 Nebula in Orion.

Pete Morris gave a very interesting “What Is” talk on Rainbows. There is a fair bit of mathematics in achieving a rainbow: the drop size (0.05mm – 2mm diameter) the altitude of the sun (below 40 degrees) fixed inner bow and outer bow angles. The intensity of  the colours depends on the drop-size – bigger drops = deeper colours and did you know that the cross section of a double rainbow begins AND ends with red? And that the blue sky between the bows is always darker than the sky above?

The “Main event” for November was a video on the Space Race (Part I). The Russia / USA

competitive spirit was the ultimate catalyst for great expenditure and (eventually) great achievement there.

 

 

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

 

Mercury in Ophiuchus:   mag  -0.3,  rises 3.52 am,  sets  4:55 pm,  Illum 69%

 

Venus in Ophiuchus:  mag  -3.9,  rises 3.53 am,   sets 5.00 pm,   Illum 93.3%

 

Mars in Scorpius: mag  1.6,  rises 2:52 am,  sets  3:53 pm,    Illum 96.4%

 

Jupiter in Virgo: mag -2.0,   rises  12.09 am,  sets   12:27 pm,  Illum 99.2%

 

Saturn in Gemini:  mag  0.5,  rises  7.23 pm,   sets  6.33 am,  Illum 100%

 

Uranus in Aquarius:  mag 5.9,  rises 9.20 am,  sets 9.50 pm ,   Illum 100%

 

Neptune in Capricornus: mag  8.0, rises 7.53 am,  sets  8.40 pm,  Illum 100%

 

Pluto in Serpens: mag  13.9,  rises  4.19 am,  sets 5.02 pm,    Illum 100%

 

Sun in Sagittarius:  mag  -26.8,  rises 5.24 am,  sets  6.35 pm

 

Moon in Leo:  mag  -12.4,  rises 10.47 pm,  sets  10.03 am, Illum 76.0% - Waning Gibbous

 

 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.

 

 

Seasons Greetings

 

The committee wishes all Members a peaceful Christmas, a prosperous New Year and many starry nights.

 

 

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