The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy.

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Academic Honours for RASNZ Members
2. RASNZ Conference 2010 May 28 to 30
3. RASNZ 2010 Conference - call for papers
4. Offers to Host RASNZ 2012 Conference
5. IYA New Zealand 2009 Poster Now Available
6. The Solar System in September 2009
7. Speech by Professor Peter Gluckman at Massey University
8. RSNZ Manhire Prize for Creative Science Writing 2009
9. Reminders of coming events. See previous Newsletters
10. IYA - 100 Hours of Astronomy Awards
11. The IAU General Assembly
12. Super Planetary Nebulae
13. Mars Orbiter Shows Angled View of Crater
14. Revelations in Saturn's Rings as Equinox Approaches
15. Advert: Telescope for sale
16. Gifford-Eiby Lecture Fund
17. Kingdon-Tomlinson Fund
18. How to Join the RASNZ
19. Usual Editor for September Newsletter

1. Academic Honours for RASNZ Members

Professor Denis Sullivan, FRASNZ -------------------------------- As many members will be aware, RASNZ Fellow Denis Sullivan was appointed professor at Victoria University as from the beginning of this year.

Early in August he delivered his inaugural professorial lecture as professor of physics. His title was "The Accidental Astronomer: a Personal Tour of the World of Astrophysics."

Extrasolar planets, the details of stars, neutrino astrophysics and even white dwarfs. The world of modern astronomy presents a vast laboratory for investigating physical phenomena. In the lecture Denis Sullivan drew on his astronomy research and teaching to give a physicist's view on life and the universe.

Denis Sullivan comments on being appointed professor of physics: "I would have also been happy with professor of astrophysics, but fundamentally I'm a physicist who teaches physics at a university and does research in astrophysics based mostly on using the observational tools in the world of astronomy."

--------------------------------------------- Professor Brian Warner, RASNZ Honorary member. --------------------------------------------- In a recent letter Brian Warner thanked the members at the recent RASNZ AGM for their message of greeting. He also gave a resume of some recent awards he has received. Last year he was made an Honorary Fellow of the Royal Society of South Africa, normally reserved for overseas residents (from South Africa). Brian is one of only three local recipients. Also at the end of last year he was reinstated by the SA government funding agency as an A1 rated researcher, of which there are only about a dozen in the country. Very recently he was installed as a Fellow of his alma mater, University College London. And at the end of this year the University of Cape Town is conferring an honorary DSc.

2. RASNZ Conference 2010 May 28 to 30

 

The 2010 RASNZ conference will be held in Dunedin at the Otago Museum using the Hutton Theatre. The web site of the Otago Museum is at <http://www.otagomuseum.givt.nz>. For more information about the venue follow the links to "about us" - "facilities hire" - "facilities photo gallery" or directly to: facility pictures and information.

The conference is being hosted by the Dunedin Astronomical Society who will be celebrating the 100th anniversary of their foundation. You are invited to join us to mark the event.

The invited speaker will be Dunedin born Dr Stuart Ryder who is the Australian Gemini Scientist, managing the Australian Gemini Office hosted by the Anglo-Australian Observatory in Sydney.

The fellows speaker will be Bill Allen who has a long association with the Dunedin Astronomical Society. Bill's home site near Blenheim hosts the new 0.6m Yock-Allen Telescope at the BOOTES-3 Observatory.

There is plenty of accommodation available within a very short walking distance of the conference venue. More information about the conference, registration and accommodation will be posted on the RASNZ web site.

Planning for the conference by the enthusiastic Local Organising committee is well under way and this promises to be a great conference. There is plenty to see and do in Dunedin so start planning now to spend a few extra days down south so that you have time to take full advantage of the local amenities - how about taking scenic train ride to the Taieri Gorge or a boat trip down to the Otago peninsula and Taiaroa head to visit the Albatross colony and view other Marine mammals and birds.

Watch this space and the RASNZ website for more details as they come to hand.

3. RASNZ 2010 Conference - call for papers

 

The RASNZ Standing Conference Committee is now accepting expressions of interest in presenting papers at the 2010 conference. If you would like to give a paper at the conference we would like to hear from you now. Please send your name and probable topic to This email address is being protected from spambots. You need JavaScript enabled to view it.. In recent years we have had a very full programs and it has been difficult to fit in all requests to present papers so you are advised to contact us early. We will require abstracts by 1 April 2010 so that we can place these on the programme and website. The final deadline will be 1 May 2010 for all paper submissions.

Please note that presenters of papers are requested to provide a written version for publication in our journal Southern Stars.

4. Offers to Host RASNZ 2012 Conference

 

The RASNZ Standing Conference Committee advises that it is now seeking offers from Affiliated Societies to host the RASNZ 2012 Conference. It is hoped to hold the RASNZ Conference over a weekend of June following the transit of Venus, which occurs on Wednesday 6th June 2012. So the conference dates would probably be the weekend of June 15-17; June 22-24 is another possibility.

The Conference host society is responsible for arranging a suitable conference venue in their region. The host society also looks after conference registrations and social arrangements. The RASNZ Standing Conference Committee is responsible for selecting the papers and the speaking programme and will work with the LOC to ensure all is running smoothly. A comprehensive set of guidelines for Conference Organisers is available from the RASNZ Secretary <This email address is being protected from spambots. You need JavaScript enabled to view it.>.

Proposals to host the 2012 RASNZ Conference should include a possible location and venue and why the local Society would like to host the Conference.

Any Affiliated Society that wishes to be considered as hosts for this event should email their proposal to the RASNZ Secretary <This email address is being protected from spambots. You need JavaScript enabled to view it.> by 31 October 2009. The RASNZ Standing Conference Committee will then consider the proposals received with a view to making a decision as to location by 31 December 2009.

5. IYA New Zealand 2009 Poster Now Available

 

Jennie McCormick writes:

The RASNZ IYA NZ 2009 posters are now for sale. The poster celebrates New Zealand's contribution to the International Year of Astronomy. To see a copy of the new poster visit http://www.rasnz.org.nz/AffSocs/poster.htm and to make an order http://www.rasnz.org.nz/AffSocs/IYAPoster.pdf

Why not give a poster to family and friends, a local school or library. You may like to consider purchasing a larger number of posters to sell to your club members? Use the poster to advertise your society within your community by adding a sticker with your society's name, logo and contact details.

The IYA New Zealand 2009 Poster is in full colour and A1 size, approximately 59.5 cm x 84 cm. All posters are packaged in poster tubes and sent by standard parcel post around New Zealand, 1 - 3 days delivery.

How to order your copy/copies:

Please send an email to Jennie McCormick This email address is being protected from spambots. You need JavaScript enabled to view it. with your name, delivery address and the number of posters you require. Once done, make payment to the Royal Astronomical Society of NZ. For costs and orderings details please go to http://www.rasnz.org.nz/AffSocs/IYAPoster.pdf. Alternatively you can order and pay by credit card on line by visiting the RASNZ sales page: http://www.rasnz.org.nz/Sales/Sales.html.

6. The Solar System in September 2009

 

The usual notes on the visibility of the Planets for September 2009 have been placed on the RASNZ web site: http://www.rasnz.org.nz/SolarSys/Sep_09.htm. Notes for October 2009 will be in place in a few days.

The southern spring equinox is on September 23, with the Sun on the equator at little after 9 am. NZDT starts on the last Sunday of September, which is the 27th this year. To keep to NZDT, clocks should be put forward (at 2 am NZST). New Zealand clocks will then be 13 hours ahead of UT (aka GMT).

The planets in september

The evening sky - mercury, jupiter and saturn

Mercury will set over two hours after the Sun at the beginning of September. The planet will be due west with an altitude of some 16 degrees 45 minutes after sunset. With a magnitude 0.6 it should be easy to find in the darkening sky.

Over the following evenings, Mercury will get steadily lower and become less bright making it an increasingly difficult object as it closes in on the Sun. By the middle of the month it will be lost in the evening twilight.

Mercury is at inferior conjunction on September 20, after which it becomes a morning object, rising shortly before the Sun, but to low in the brightening sky for observation.

Saturn is also nominally in the evening sky setting just over an hour after the Sun on the first. It will be a difficult object in the evening twilight, only 6 degrees up half an hour after sunset.

The Earth moves through Saturn's ring plane on the 4th - that is the rings will appear edge on. The phenomenon is going to be difficult to observe, and will not occur again until March 2025 (and that in the morning sky with Saturn rising only a short time before the Sun will be no easier to see!).

Saturn's rings were edge on to the Sun on August 10 so since that date the Sun has been illuminating the northern face of the rings, while from Earth we have had a view of the southern face.

Jupiter having been at opposition mid August, will be well placed for viewing all evening throughout September and, as Saturn and Mercury disappear from the evening sky, be the only planet visible.

On September 3, immediately after sunset Jupiter will be visible with none of the Galilean satellites visible clear of the planet. Europa and Ganymede will be in transit across the face of the planet, while Io and Callisto will be in eclipse in Jupiter's shadow. From NZ the event will be short lived with Io due to move out of eclipse just before 6.30 pm. This ranges from nearly half an hour after sunset in Auckland to barely 10 minutes after in Invercargill. Io will reappear close to Jupiter's east limb. Some quick telescope viewing immediately after sunset should make the reappearance visible from most parts of the country.

The last satellite to disappear from view is Ganymede which begins its transit across the face of Jupiter at 4.45 pm, well before sunset in NZ. The last of the Moons to appear will be Callisto slowly emerging from Jupiter's shadow at about 8.35 pm. It will then be only 6 arc-seconds from Io now further out from Jupiter.

The separation of Jupiter and Neptune will increase slightly during September. On the 30th, the two will be just 0ver 6.5 degrees apart. Mid evening, the 86% lit Moon will be a similar distance from Jupiter and some 3 degrees from Neptune. The almost full moon also passes the two planets on September 3.

The morning sky - venus and mars

Venus is the third planet that closes in on the Sun during September, although its brightness should make sure it doesn't get lost in the morning twilight. By the end of the month, it will rise only 50 minutes before the Sun, so will be a very low object before sunrise.

On the morning of September 17, the Moon, a very thin crescent, will be two and a half degrees to the upper right of Venus. They will be very low in the twilight.

The 1.4 magnitude star Regulus will be to their lower right about 3 degrees away. Three mornings later, Venus will be alongside Regulus, with the star 1 degree to the right of the planet. The following morning, 21 September, Regulus will be half a degree directly above Venus. Binoculars are likely to be needed to show up the star. The two will be almost 8 degrees up 10 minutes before sunrise.

Mars will start to rise earlier in the morning after several months rising at almost the same time. By the end of month, after the start of NZDT, it will rise about 3.30 am in Auckland and almost an hour later at Invercargill.

During September, Mars crosses Gemini so that by the end of the month it will be 6 degrees above Pollux, which at magnitude 1.2 will be a little fainter than the planet.

The 38% lit Moon will pass within 2 degrees of Mars on the morning of September 14, as seen from NZ. From the Arctic the Moon will be seen to occult the planet.

Uranus is following Jupiter in the sky and is at opposition on September 17, about 9 hours before Saturn is at conjunction. So it will be observable all evening by the end of the month. Uranus is in Pieces during September, close to and moving towards the constellation's border with Aquarius.

Neptune is Capricornus, across Aquarius from Uranus and remains fairly close to Jupiter during September.

Brighter asteroids:

(1) Ceres is an early evening object following Saturn towards the Sun. The asteroid is in Virgo throughout the month. It will set about 2.5 hours after the Sun on the 1st, but only about 75 minutes later at the end of the month. At magnitude 8.8 it will then be a difficult object.

(2) Pallas is too close to the Sun to observe throughout September

(3) Juno is at opposition on September 22, so will be observable all evening by the end of the month. With a magnitude brightening from 8.2 to 7.8 it is the brightest asteroid and should be readily visible in binoculars.

(4) Vesta, in the morning sky Cancer, will rise some 100 minutes before the Sun on the 1st and about 2 hours before by the end of the month. It will brighten very slightly from magnitude 8.5 to 8.4.

(18) Melpomene follows Juno across the sky. By the end of September it will rise about 30 minutes after sunset. The asteroid is in Cetus and brightens from magnitude 8.7 to 7.9 during September, so that by the end of the month it is only slightly fainter than Juno.

Brian Loader

7. Speech by Professor Peter Gluckman at Massey University

 

Professor Gluckman has been appointed Chief Science Advisor to the Prime Minister. He gave his first speech in this role at Massey University in July. The text of his speech can be downloaded as a 13 page pdf format document from (all one long line): http://sciencenewzealand.org/content/download/1371/11983/version/1/file/09-07-17+Massey+Speech +-+Formatted+for+website.pdf

This is a fairly wide ranging look at the role of scientific research in New Zealand and its funding. There are possible implications for astronomy here.

Thanks to Roland Idaczyk for bringing this to our attention.

8. RSNZ Manhire Prize for Creative Science Writing 2009

 

Edge of the universe

"I live at the edge of the universe, like everybody else." -- Bill Manhire

This year we are celebrating the International Year of Astronomy. Ever since Galileo first aimed his telescope at Jupiter's moons, technology has been enlarging our knowledge of the universe.

We now know our own insignificance and isolation and yet we have immense power to communicate as never before. The race of humans is isolated in space and time and yet where, as individuals, do we go to be alone?

You are invited to write between 2,000 and 3,000 words about the place - past or present or future - of human beings in the universe.

There are two categories, fiction and non-fiction. A cash prize of $2,500 will be awarded to the winner of each category. The closing date for entries is Tuesday 22 September 2009.

The Manhire Prize for Creative Science Writing is organised by the Royal Society of New Zealand in association with the New Zealand Listener magazine and the International Institute of Modern Letters at Victoria University of Wellington.

For more information, terms and conditions, and entry forms visit www.royalsociety.org.nz or contact: Danae Staples-Moon, Tel. 04 470 5770 or Email. This email address is being protected from spambots. You need JavaScript enabled to view it.

9. Reminders of coming events. See previous Newsletters

 

The Phoenix Astronomical Society - Winter Astrocamp: Fri 21 - Sun 23 August 2009 at the Carterton RSA.

Details and a registration form are available at www.AstronomyNZ.org.nz. Any queries please contact Antony Gomez This email address is being protected from spambots. You need JavaScript enabled to view it. or on 021 253 4979


Herbert Astronomy Weekend: Fri 18 - Sun 20 September at Camp Iona, Herbert.

Contact Phil Barker for further information: This email address is being protected from spambots. You need JavaScript enabled to view it.

--------------------- Waharau Dark Sky Weekend

Arranged by the Auckland Astronomical Society, this will take place over the weekend Friday 18 to Sunday 20 September.

Further details can ve found on the AAS website: <http://www.astronomy.org.nz>


Auckland Astronomical Society Burbidge Dinner

The annual Dinner will be held on Saturday, the International Year of Astronomy at Novotel Ellersile on the 7th November 2009.

Contact Andrew Buckingham This email address is being protected from spambots. You need JavaScript enabled to view it. for more details.


The Letters of Beatrice Hill Tinsley

The 20-part series The Stars are Comforting - The Letters of Beatrice Hill Tinsley (1941 - 1981) is being broadcast 7.00 p.m., Wednesdays starting from 5 August on Radio New Zealand Concert.

For more information about, and access to these programmes visit http://www.radionz.co.nz/concert/home

10. IYA - 100 Hours of Astronomy Awards

 

Congratulations to Ron Fisher and the Levin StarGazers who won the international 100HA Award Three section for Community Outreach during the 100HA events in April. There were 2370 registered events worldwide, so this is a fantastic achievement and a credit to Ron and all the other people who contributed to the event. The Celestron Sky Scout prize will surely be of great benefit to the club and all who come along to our regular star parties.

Also congratulations to Paul Moss, who was Highly Commended in Award Eight for "Outstanding Individual within a registered 100 Hours of Astronomy event".

Based on a report by Mike White in New Zealand Astronomers during July.

11. The IAU General Assembly

 

Alan Gilmore reports on the meeting held in Rio de Janeiro.

The International Astronomical Union's 23rd General Assembly ended in Rio de Janeiro last Friday [August 14th]. It was a feast of information and debate on current research and new discoveries. Six week-long symposia covered areas of astronomy ranging from icy bodies in the solar system to the co-evolution of galaxies and their central black holes. Running concurrently with them were 16 Joint Discussions, two-day affairs covering just about everything else, and Special Sessions liking diverse areas.

As well there were Plenary Reviews on six mornings before the other meetings began. At these an expert selected from a symposium gave overview of the science to be covered in the symposium. And, in case one’s head wasn’t full after a day of talks, there were after-work Invited Discourses on four evenings. There an expert in a field talked about his or her subject. Their titles show the range: ‘The Legacies of Galileo’, ‘Water on Planets’, ‘Evolution of the Structure of the Universe’ and ‘Do Low Luminosity Stars Matter?‘. To the last title’s question Maria Teresa Ruiz of the University of Chile put up a slide answering ‘Yes!’. She then filled a fascinating hour justifying her answer.

Each Symposium and Joint Discussion was organised by a Division (explained below) covering a particular area of interest. Special Sessions (SpSs) were organised for diverse areas of astronomy sharing a common interest. Sps 2 reviewed the International Year of Astronomy. Sps 3 Astronomy in Antarctica had contributions on the Icecube neutrino detector, the BICEP cosmic microwave background telescope at the south pole, plans for observatories on the high dry Antarctic domes, and a fascinating talk on detection of past supernovae and solar cycles in ice cores.

Honours were bestowed. The annual Gruber Cosmology Prize was awarded jointly to Wendy Freedman, Robert Kennicutt and Jeremy Mould for their leadership in the definitive measurement of the Hubble constant. The recipients gave a three-part lunch-time lecture on the topic.

Among all this there were IAU business meetings. National Representatives had three meetings to attend before each of the two General Assembly (GA) meetings. Everyone is expected to attend the GA meetings. These were pretty routine; nothing like the fierce Pluto debates at the Prague GA of 2006. There was a financial scandal to spice things up, but it wasn’t featured. Unlike Prague, where several TV crews turned up to the second GA‘s Pluto debate, the news media took no interest at all.

Specialist interests are looked after by Commissions.  These range from Commission 4 (C4)
Ephemerides through areas like C15 Physical Studies of Comets and Minor Planets, C46
Astronomy Education and Development, C50 Protecting of Existing and Potential Observatory
Sites to C55 Communicating Astronomy with the Public. Each Commission is part of a Division.
Divisions cover the broad areas of astronomy: Division I (divisions have Roman numerals)
groups all the Commissions dealing with fundamental astronomy: astrometry, time keeping,
numerical standards and the like. D III covers planetary systems sciences. D XII Union Wide
Activities gathers the general purpose commissions like C5 Documentation and Astronomical
Data, and C6 overseeing the quaintly named Central Bureau for Astronomical Telegrams.
Each Commission and each Division had a business meeting. Commissions have to justify their
existence at every GA. One or two didn’t and were disbanded.  Others decided to amalgamate.

And, if this wasn’t enough work, many Commissions also have specialist Working Groups to cover some sub-speciality. C5 has a Working Group (WG) on Virtual Observatories, Data centres and networks. C41 has one for Astronomy and World Heritage.

Most days began at 9 and ended at 5:30 with the Invited Discourses going on till 7 pm. Most of us were in hotels in Copacabana, a 20 minute Metro ride from the conference centre in Centro. So getting enough sleep was quite a challenge.

All meetings were at the Centro de Convencoes SulAmerica in Centro. This is a large place, still being completed, well suited for the assembly. Conference halls and smaller meeting rooms were on three levels. A large area for poster papers was on the ground floor where the morning and afternoon coffees were served.

12. Super Planetary Nebulae

 

Press release from the Royal Astronomical Society, London.

Date: 14th August 2009

Issued by: Dr Robert Massey Press and Policy Officer Tel: +44 (0)794 124 8035, +44 (0)20 7734 4582 E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. Web: www.ras.org.uk

Super planetary nebulae (ras pn 09/51)

A team of scientists in Australia and the United States, led by Associate Professor Miroslav Filipovic from the University of Western Sydney, have discovered a new class of object which they call "Super Planetary Nebulae." They report their work in the journal Monthly Notices of the Royal Astronomical Society.

Planetary nebulae are shells of gas and dust expelled by stars near the end of their lives and are typically seen around stars comparable or smaller in size than the Sun.

The team surveyed the Magellanic Clouds, the two companion galaxies to the Milky Way, with radio telescopes of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Australia Telescope National Facility. They noticed that 15 radio objects in the Clouds match with well known planetary nebulae observed by optical telescopes.

The new class of objects are unusually strong radio sources. Whereas the existing population of planetary nebulae is found around small stars comparable in size to our Sun, the new population may be the long predicted class of similar shells around heavier stars.

Filipovic's team argues that the detections of these new objects may help to solve the so called "missing mass problem" - the absence of planetary nebulae around central stars that were originally 1 to 8 times the mass of the Sun. Up to now most known planetary nebulae have central stars and surrounding nebulae with respectively only about 0.6 and 0.3 times the mass of the Sun but none have been detected around more massive stars.

The new Super Planetary Nebulae are associated with larger original stars (progenitors), up to 8 times the mass of the Sun. And the nebular material around each star may have as much as 2.6 times the mass of the Sun.

"This came as a shock to us", says Filipovic, "as no one expected to detect these object at radio wavelengths and with the present generation of radio telescopes. We have been holding up our findings for some 3 years until we were 100% sure that they are indeed Planetary Nebulae".

Some of the 15 newly discovered planetary nebulae in the Magellanic Clouds are 3 times more luminous then any of their Milky Way cousins. But to see them in greater detail astronomers will need the power of a coming radio telescope - the Square Kilometre Array planned for the deserts of Western Australia.

FURTHER INFORMATION Accompanying images are available from http://staff.scm.uws.edu.au/~evan/PNE/

An optical image from the 0.6-m University of Michigan/CTIO Curtis Schmidt telescope of the brightest Radio Planetary Nebula in the Small Magellanic Cloud, JD 04. The inset box shows a portion of this image overlaid with radio contours from the Australia Telescope Compact Array. The planetary nebula is a glowing record of the final death throes of the star. (Optical images are courtesy of the Magellanic Cloud Emission Line Survey (MCELS) team).

The MNRAS paper is available as an Early View article from http://www3.interscience.wiley.com/journal/122542603/abstract

CONTACT Professor Miroslav Filipovic University of Western Australia Tel: +61 (0)41 1547892 Mob: +61 (0)41 1547892 E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Forwarded by Karen Pollard

13. Mars Orbiter Shows Angled View of Crater

 

TUCSON, Ariz. -- The high-resolution camera on NASA's Mars Reconnaissance Orbiter has returned a dramatic oblique view of the Martian crater that a rover explored for two years.

The new view of Victoria Crater shows layers on steep crater walls, difficult to see from straight overhead, plus wheel tracks left by NASA's Mars Exploration Rover Opportunity between September 2005 and August 2007. The orbiter's High Resolution Imaging Science Experiment camera shot it at an angle comparable to looking at landscape from an airplane window. Some of the camera's earlier, less angled images of Victoria Crater aided the rover team in choosing safe routes for Opportunity and contributed to joint scientific studies.

The new Victoria Crater image is available online at: http://www.nasa.gov/mission_pages/MRO/multimedia/mro20091012a.html and as a sub-image of the full-frame image at: http://hirise.lpl.arizona.edu/ESP_013954_1780

Another new image from the same camera catches an active dust devil leaving a trail and casting a shadow. These whirlwinds have been a subject of investigation by Opportunity's twin rover, Spirit.

The new dust devil image is available online at: http://www.nasa.gov/mission_pages/MRO/multimedia/mro20091012b.html and as a sub-image of the full-frame image at: http://hirise.lpl.arizona.edu/ESP_013545_1110 .

The Mars Reconnaissance Orbiter has been studying Mars with an advanced set of instruments since 2006. It has returned more data about the planet than all other past and current missions to Mars combined. For more information about the mission, visit: http://www.nasa.gov/mro .

The Mars Reconnaissance Orbiter is managed by the Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technologies Corp., Boulder, Colo.

From a JPL press release, forwarded by Karen Pollard

14. Revelations in Saturn's Rings as Equinox Approaches

 

Thanks to a special play of sunlight and shadow as Saturn continues its march towards its August 11 equinox, recent images captured by NASA's Cassini spacecraft are revealing new three-dimensional objects and structures in the planet's otherwise flat rings.

Through the detections of shadows cast upon the rings, a moonlet has been spotted for the first time in Saturn's dense B ring and narrow vertical structures are seen soaring upward from Saturn's intricate F ring.

The new images can be found at <http://ciclops.org>, <http://saturn.jpl.nasa.gov> and <http://www.nasa.gov/cassini> .

The search for three-dimensional structures in Saturn's rings has been a major goal of the imaging team during Cassini's "Equinox Mission," the 27-month-long period containing exact equinox -- that moment when the sun is seen directly overhead at noon at the planet's equator. This novel illumination geometry, which occurs every half-Saturn-year, or about 15 Earth years, lowers the sun's angle to the ring plane and causes out-of-plane structures to cast long shadows across the rings' broad expanse, making them easy to detect.

Saturn's rings are hundreds of thousands of miles or kilometers wide, but the main rings -- D, C, B and A rings (working outward from the planet) -- are only about 30 feet, or 10 meters, thick. These main rings lie inside the relatively narrow F ring. The thinness of the rings -- well below the resolving power of the spacecraft's cameras -- makes the determination of vertical deviations from them difficult through routine imaging. Solid evidence of these newly seen structures and others like them becomes available only during the period of equinox when features protruding above and below the rings can cast shadows.

The new moonlet in the B ring, situated about 300 miles, or 480 kilometers, inward from the outer edge of the B ring, was found because of a shadow 25 miles, or 41 kilometers, long that it throws on the rings. The shadow length implies the moonlet is protruding about 660 feet, or 200 meters, above the ring plane. If the moonlet is orbiting in the same plane as the ring material surrounding it, which is likely, it must be about 1,300 feet, or 400 meters, across. Unlike the band of moonlets discovered in Saturn's A ring earlier by Cassini, this object is not attended by a propeller feature. The A ring moonlets, which were not imaged directly, were found because of the propeller-like narrow gaps on either side of them that they create as they orbit within the rings. The absence of a propeller feature surrounding the new moonlet is likely because the B ring is denser and the ring material in a dense ring would be expected to fill in any gaps more quickly than in a less dense region like the mid-A ring. Also, it may simply be harder in the first place for a moonlet to create propeller-like gaps in a dense ring.

In recent weeks scientists also have collected a series of images of shadows being cast by vertically extended structures or objects in the F ring. One image shows the shadow of what appears to be a vertically extended object in the core of the F ring, while another image may show the shadow of an object on an inclined orbit which has punched through the F ring and dragged material along in its path. A third image shows an F-ring structure casting a shadow long enough to reach across the wide Roche Division and appear on the A ring. Imaging scientists are working to understand the origin of these structures.

New sights such as these -- and the questions they raise and the insights they may provide -- will continue in the coming days of Saturn's equinox.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the U.S., England, France, and Germany. The imaging operations center and team leader (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

-- From a press release from the Cassini Imaging Central Laboratory at the Space Science Institute, Colorado and forwarded by Karen Pollard

15. Advert: Telescope for sale

 

Philip Ivanier has a telescope for sale. The details he sends are:

Celestron NexStar 8se Celestron Tripod Is like new condition (no scratches, dings or dents)! Comes with hard case for storage and transport. Laser Star Sight

I have been the only owner of the scope and it has been very well looked after.

Anyone interested should contact Philip at: <This email address is being protected from spambots. You need JavaScript enabled to view it.>

16. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

For an application form contact the Executive Secretary This email address is being protected from spambots. You need JavaScript enabled to view it., 14 Craigieburn Street, Darfield 7510.

17. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants may be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Full details are set down in the RASNZ By-Laws, Section J.

For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it., 14 Craigieburn Street, Darfield 7510.

18. How to Join the RASNZ

A membership application form and details can be found on the RASNZ website http://www.rasnz.org.nz/InfoForm/membform.htm. Please note that the weblink to membership forms is case sensitive. Alternatively please send an email to the membership secretary This email address is being protected from spambots. You need JavaScript enabled to view it. for further information.

The annual subscription rate is $75. For overseas rates please check with the membership secretary, This email address is being protected from spambots. You need JavaScript enabled to view it..

19. Usual Editor for September Newsletter

 

Please send any contributions to the September Newsletter to Alan Gilmore as usual: Alan Gilmore Phone: 03 680 6000 P.O. Box 57 This email address is being protected from spambots. You need JavaScript enabled to view it. Lake Tekapo 7945 New Zealand

Pauline and Brian Loader This email address is being protected from spambots. You need JavaScript enabled to view it.

20 August 2009


Newsletter editor:

Alan Gilmore   Phone: 03 680 6000
P.O. Box 57   Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand