April 2009


Welcome to the latest newsletter which, we hope, you will enjoy reading.
In addition to the topics normally included in the newsletter, there is a book review by Johan Retief. The attachment is a New Scientist article on gravity holes or voids.

We welcome the following new members to the Club: – Billy Robinson, Oelof Heckroodt, Wendy Booyens, and Cliff & Joyce James

Our application to become an ASSA Centre should be heard at the next ASSA committee meeting towards the end of April. We will informed you once the decision has been made.

The constellation of Leo is visible to the north/north-east, high in the sky, after approximately 9 pm. Like Scorpius, its shape resembles the animal after which it is named. The dominant feature of the upside down lion is the Sickle. From the southern hemisphere, this looks like an inverted, back-to-front question mark, and forms the chest and head of the lion. The bright star at the heart of the lion is Regulus. The planet visible near Leo is Saturn.

Dr Pieter Kotze, from the Hermanus Magnetic Observatory, gave a very interesting talk on the source and nature of the earth’s magnetosphere, and its role in protecting the earth. He also described the adverse effects of disruption of the magnetic field by solar events like sun spots, coronal mass ejections and the solar wind, which can interfere with bird migration, satellite function and communication systems.

The monthly Thursday meetings will be held at 7 pm on on the following days:
30 April (details below) 20 August
28 May 24 September
25 June 22 October
23 July 19 November
17 December

The topic for April’s meeting is the postponed presentation on Astro-photography, to be given by Pierre de Villiers and Steve Kleyn. Please bring your cameras so that, weather permitting, you will be able to apply your new skills.

Interest groups

Fifteen people attended the inaugural Astronomy for Absolute Beginners meeting on 17 March. Using eyesight, binoculars and the club’s Dosbonian telescope, they were able to identify a number of constellations and stars. A further meeting will be arranged when other constellations become visible.
Twelve members participated in a lively and informative discussion on cold dark matter at the Cosmology interest group meeting on 30 March. The topic for discussion in April will be dark energy.

International Year of Astronomy Club members participated in the Orion star count which took place from 2-5 April. Most managed to see stars up to magnitude 5, but John Retief reached magnitude 6 – probably demonstrating the effect of greater light pollution in Hermanus than in Fisherhaven. The club will be involved in other IYA activities in 2009.

Hermanus Primary School Hobbies Day The club will have a stand this event which takes place on 1 May. The stand will include a running astronomy DVD on display on the subject of astronomy, and Pierre de Villiers’ and the club’s Dobsonian telescopes will also be on display. Members of the public are welcome to attend the event at the school.

Wortelgat Outreach Trust A long-term astronomical educational project is soon to be started with this Trust. Committee members will be meeting Trust representatives soon and details will be announced at the May club meeting. The Trust has an 8” telescope and has asked the club to show them yow to use it. The club also hopes to be able to become involved in regular educational sessions on astronomy.

The planning application for the observatory has been submitted to the Municipality and we await its progress through the various committee stages. We now have to set our sights on fund- raising for the project. An arrangement with the Whale Festival Media & Marketing Company has been agreed in order to raise most of the funds for the first phase of construction. More details of the fund raising schemes will be sent to you, shortly, via a Special Observatory Newsletter, explaining the ideas and suggesting ways in which you can help and participate.

At last month’s club night, we commenced a ‘Friends of the Observatory’ pledge campaign to assist with the initial funding of the planning application. At each monthly meeting, the pledge campaign will continue until the funds are needed to settle accounts as they arrive. Several members have made pledged donations and we thank them for their help and support in this most exciting project.

Remember, the Observatory is not just a short time project, but will be there forever, and a huge landmark for Hermanus, with a new attraction to the town. You will be a part of it.

1 NASA’s Kepler mission successfully launched into space from Cape Canaveral aboard a United Launch Alliance Delta II ROCKET ON 6 March. Kepler is designed to find the first Earth-size planets orbiting stars at distances where water could pool on the planet’s surface. Liquid water is believed to be essential for the formation of life.

“It was a stunning launch,” said Kepler Project Manager James Fanson of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Our team is thrilled to be a part of something so meaningful to the human race — Kepler will help us understand if our Earth is unique or if others like it are out there.”

2 Sunspots The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower. No sunspots were observed on 266 of the 2008 year’s 366 days (73%). The last cycle as low as this was way back in 1913! Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year’s 90 days (87%).

It adds up to one inescapable conclusion: “We’re experiencing a very deep solar minimum,” says solar physicist Dean Pesnell of the Goddard Space Flight Center. “This is the quietest sun we’ve seen in almost a century,” agrees sunspot expert David Hathaway of the Marshall Space Flight Center.

Let’s hope that this ultra-low cycle doesn’t result in a series of hyper activity when serious and dangerous solar flares and Corona Mass Ejections. This seems to have been a fairly common reaction in history

Despite its recent demotion from planet to minor or dwarf planet, our journey through the planets of the solar system ends with Pluto and its moons.

Pluto was discovered by American Astronomer Clyde Tombaugh in 1930 at the Percival Lowell Observatory in Arizona. It was not named after a Walt Disney dog with floppy ears, but after the Roman god of the underworld. Some say that Tombaugh named it after Lowell, whose initials are the first two letters of Pluto.
Pluto circles the sun on a very eccentric orbit, varying from 4.4 to 7.7 billion kms. For the most of its orbit, it is the outermost planet. However, between 1979 and 1999 Pluto was actually closer to the sun than NeptuneDue to the changes in orbit over time, Pluto has a unique atmsophere that transforms at various stages of its orbit. As its orbit approaches the Sun, its atmosphere begins to form. The frozen atmosphere melts as it comes closer, but, sis Pluto moves further out, its atmosphere freezes.
Pluto rotates in the opposite direction from most other planets and, like Uranus, the plane of its equator is almost at right angles to the plane of its orbit.
Vital statistics
• Diameter: 2324 km (1444 miles).
• Surface composition: Nitrogen, carbon monoxide, methane and water ices
• Average surface temperature: -233ºC (-382ºF)
• Mass: 0.002 (Earth = 1) (Earth = 1)
• Average distance from the Sun: 5.9 billion kilometres.
• Rotation Period: 6.39 Earth days (length of day)
• Orbital period around the sun: 248 Earth years (length of year)
• Rings = 0
• Moons = 1
• Average distance between Pluto and its moon 19,600 Kms Moon
Pluto’s moon, Charon, was discovered in 1978. Its diameter is 1212 km (753 miles), more than half as wide in size as Pluto, and the Pluto-Charon system is like a double planet. Charon orbits Pluto every 6.4 days and has a synchronous orbit (the pair show the same face to each other all the time). To an observer on the planet, Charon appears to be stationary in the sky like a geostationary satellite orbiting the Earth.
In the mid 1990s, NASA began development of the Pluto-Kuiper Express spacecraft. In 2000, however, for budgetary reasons, a stop-work order on the project was issued. NASA then began to talk of a plan of a probe arriving before 2020, costing less than $500 million. From a competition, a team called New Horizons was selected to build a spacecraft that will study Pluto, Charon and several Kuiper Belt objects during a series of flybys. Launched in 2006, it will reach Pluto in 2015.
.Reference: www.aerospaceguide.net

Amateur Astronomy Pocket Skyguide by Mark R. Chartrand III, published by Newnes Books 1984, ISBN 0-600-35708-2. Size: A5. 272 pages.

How is the magnitude scale constructed? How are telescopes mounted? What is the relative light efficiency of your binoculars for star gazing? What are multiple stars? This book, published in soft cover but on durable paper, is the beginner’s bible! Every opening of the book brings you to a new subject, left page text, right page illustrated. It is written in an easily understandable language, the presentation is excellent. This book is a must for all junior amateur astronomers. Is it available? Of course! I have recently ordered a used copy from www.alibris.com for R20.71 (delivery costs were about R110.00) and received the book within four weeks. My copy is in excellent condition.


John Saunders (Chairman) 028 314 0543
Steve Kleyn (Technical Advisor) 028 312 2802
Pierre de Villiers (Treasurer) 028 313 0109
Irene Saunders (Secretary) 028 314 0543
Pierre Hugo (Auditor & librarian) 028 312 1639
Jenny Morris (Newsletter editor) 071 350 5560
Derek Duckitt (IT & website co-ordinator) 082 414 4024
Johan Retief (Monthly sky maps) 028 315 1132
Piet Daneel 028 314 0347

Leave a Reply

Your email address will not be published. Required fields are marked *