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. Stu Parker Finds Hypernova
2. The Solar System in September
3. Herbert Astronomy Weekend
4. Harry Williams Astrophotography Competition
5. Mt John Community Nights
6. Gissy Gathering - Labour Weekend
7. NACAA 2012
8. Third International Starlight Conference
9. RASNZ Conference 2012
10. Tom Gehrels
11. Juno Spacecraft Off to Jupiter
12. Kepler Studies Planetary Nebula
13. Active Black Hole Pair Discovered
14. Pluto's Fourth Moon
15. Earth's First Trojan Asteroid Discovered
16. 16-inch Dobsonian for Sale
17. Gifford-Eiby Lecture Fund
18. Kingdon-Tomlinson Fund
19. How to Join the RASNZ
20. Quotes

1. Stu Parker Finds Hypernova

On the 25th July Stuart Parker of Oxford, Canterbury discovered his 18th supernova. It quickly turned out to be the most exciting and interesting object he has discovered to date.

Discovered at a faint 18.3r magnitude in NGC6925, in Microscopium, the object was rapidly brightening. Stu's Australian collaborators in the Backyard Observatory Supernova Search (BOSS) provided confirmation. Greg Bock was away at Leyburn and was able to quickly get the confirmation image, while Colin Drescher away at Queensland Astrofest was able to supply highly accurate positional and magnitude data. Peter Marples logged the possible discovery on the IAU Central Bureau's (CBAT) Transient Objects Confirmation Page (TOCP) and sent the advice to CBAT. BOSS members also made contact with a Nidia Morrell of the Las Campanas Observatory in Chile. She obtained spectra using one of the 6.5m Magellan telescopes and found that object was a type IIb event -- a hypernova -- because lines were broad. The spectrum was similar to that of supernova 1993J a few days prior to maximum light.

Things happened quickly. Stu got an email from Dan Milisavljevic of the South African Large Telescope (SALT), a contact he made at the resent supernova conference, saying "Stu, looks like you may have found something exciting." When the 11m SALT telescope in South Africa and the 6.5m Magellan scopes in Chile are buzzing you know you have achieved something special.

The object was given the preliminary designation PSN J20342262 -3158236, based on its 2000 co-ordinates, and images were posted at http://www.rochesterastronomy.org/snimages/ . After spectroscopic confirmation that the object was a supernova, it was given the designation 2011ei and officially announced in Central Bureau Electronic Telegram (CBET) 2777.

Raffaella Margutti and colleagues of Harvard University reported that the spectral properties of 2011ei show a good match to the energetic type- IIb 'hypernova' 2003bg approximately 7 days before maximum light. The Swift satellite observed the field of 2011ei on August 3 but did not detect any x-rays.

Laura Chomiuk and Alicia Soderberg of the Harvard-Smithsonian Center for Astrophysics detected SN 2011ei with the EVLA radio telescope array. On August 5.2 UT it showed a signal strength of 143 +/- 30 microJansky at 5.0 GHz.

Peter Marples wrote the following tribute to Stu's success: "So again, a huge congratulations to Stu Parker and his wife Lynne who supports him in his dedication. They both run a dairy farm in New Zealand and somehow Stu manages 600 plus images per clear night, then blinks them and still manages to get the cows milked. I can't tell you how many hours this involves but it's lots!

Goes to show that YOU an amateur astronomer can contribute to the science of this great hobby with pretty much standard off the shelf gear, you just got to add time and effort."

-- thanks to Peter Marples for background on the discovery and Stuart Parker for updates on the preliminary science results.

2. The Solar System in September

The usual notes on the visibility of the Planets for September 2011 are on the RASNZ web site: http://www.rasnz.org.nz/SolarSys/Sep_11.htm. Notes for October 2011 will be on line in a few days.

The southern spring equinox is on September 23 with the Sun on the equator at 9.05 pm. NZDT starts about 29 hours later, on the morning of Sunday 25 September.

The planets in september

In the early evening Saturn gets very low and is passed by Venus at the end of September as it emerges from the Sun.

Jupiter rises later in the evening but is still best seen before dawn. Mars remains a morning object as well. Mercury is too close to the Sun to view.

Early evening sky - venus and saturn

Venus is an early evening object throughout September but on the 1st it sets only 15 minutes after the Sun. Thus it is not likely to be seen then. By the end of the month the planet will set about one hour later than the Sun. 20 minutes after sunset Venus should be visible about 6° above the horizon to the west.

Towards the end of September Venus will move past Saturn. The two are closest on September 28 and 29. While Saturn is not likely to be visible to the eye Venus should be, low to the west, shortly after sunset. Binoculars are then likely to show Saturn.

Also on the 28th the moon, a very thin crescent only 1% lit, will be 5° to the left of Venus. Again, having found Venus, it may be possible to see the moon using binoculars. It will be a very challenging observation, as New Moon occurs barely 20 hours earlier.

Saturn sets at about 9pm at the beginning of September so will be visible in the evening sky, low to the west, once the sky darkens. It gets steadily lower during the month, to set soon after 8pm (NZDT) by September 30, not quite an hour after the Sun. As a result, Saturn will become lost to view in the evening twilight during the month.

Late evening and morning sky

Jupiter will rise close to 11pm for most of New Zealand at the beginning of September, but after 11.30pm in the far south. The time at which Jupiter rises will advance by two hours during the month, but the start of NZDT pushes this back one hour to about 10pm NZDT.

Although by the 30th Jupiter will be easily visible to the northeast by midnight, it will still be better placed for viewing in the morning a while before sunrise when the planet will be to the northwest.

On the night of September 16/17 the 85% lit moon will be 5° from Jupiter. At midnight the two will be to the northeast with the moon to the left of the planet. By the morning of the 17th, before sunrise, the pair will be to the northwest, the rotation of the sky bringing the moon almost directly below Jupiter. The star Hamal will be on the opposite side of the moon and just slightly further away. At magnitude 2.0, Hamal is the brightest star in Aries.

Morning sky

Mars continues to rise in the morning a little over 2 hours before the Sun. The planet will be moving to the east, at first in Gemini and then in Cancer from the 16th. Mars remains as magnitude 1.4 so it will be necessary to look for it at least 45 minutes before sunrise, otherwise the brightening dawn sky will swamp out the planet. 45 minutes before sunrise the planet will be to the northeast with an altitude ranging from 10° in the south of NZ to 16° in the north.

The brightest star in Gemini, Pollux or beta Gem, will be 6° below and a little to the left of Mars on the morning of the 9th of September. Procyon, at magnitude 0.5 the brightest star in Canis Minor, will be 17° away on the other side of Mars. The planet and two stars will form an almost straight line.

The crescent moon will be closest to Mars on the morning of the 24th when it will be 7.5° to the right of the planet. The previous morning it will be a similar distance to the upper left of Mars.

On the last morning of September, Mars will be on the edge of M44, "Praesepe" or the "Beehive" star cluster. It will cross the cluster between the 1st and 3rd of October.

Mercury is not observable for southern hemisphere viewers during September. It rises in the morning sky before the Sun for almost the whole of the month, but at its best at the beginning of September only 45 minutes earlier. As a result it will be too low in the twilight to see.

Mercury is at its greatest elongation, 18° west of the Sun on September 3. After that, the planet will move back towards the Sun until on September 29 Mercury is at superior conjunction. If it could be seen, Mercury would then appear to be just over 1° from the Sun. In reality it will be 59 million km beyond the Sun, and 209 million km (1.40 AU) from the Earth.


Uranus rises about 8pm early September and about 7pm (NZDT) by the end of the month, so will be suitably placed for viewing later in the evening. It will be in Pisces slowly moving in a retrograde sense. Uranus is at opposition on the 26th with a magnitude 5.7.

Neptune is in Aquarius during September at magnitude 7.8. It rises before sunset so is well placed for viewing during the evening.

Brighter asteroids:

(1) Ceres is at opposition in Cetus on September 16 at magnitude 7.6. A few nights later, on the 23rd in NZ, the asteroid will move into Aquarius. Ceres will be well placed for viewing by mid evening.

(4) Vesta is in Capricornus and beginning to fade following its August opposition. During September its magnitude increases from 6.3 to 7.0, so remains brighter than Ceres. It is also well placed for evening viewing.

(15) Eunomia will brighten to magnitude 9.0 at the end of September. It will then be in Perseus. With a declination of +37° it will be low in New Zealand skies.

(192) Nausikaa is at opposition in Aquarius on September 2 at magnitude 8.3. It will be in Aquarius about 10° from Neptune. By the end of the month it Nausikaa will have faded to magnitude 9.0.

More details and charts for these minor planets can be found on the RASNZ web site. Follow the link to asteroids 2011.

Comets:

C/2009 P1 (Garradd) is expected to be at about magnitude 8 during September. It moves from Sagitta to Hercules on September 12. The comet will be a morning object, rising about midnight.

45P/Honda-Mrkos-Pajdusáková rises less than 2 hours before the Sun in NZ, so will be very low in the dawn sky. The comet starts the month in Hydra, and crosses into Leo on the 10th. At about magnitude 8, it will be 3° to the upper right of Regulus on the morning of the 25th, with the crescent moon some 7° to the upper left of star and comet.

Further details and charts for the two comets can be found on the RASNZ web site. Follow the link to Comets 2011.

-- Brian Loader.

3. Herbert Astronomy Weekend

The Herbert Astronomy Weekend will again be held at Camp Iona from Friday September 2nd to Monday September 5th.

Camp Iona is signposted 2km to the west of Herbert, 20 km south of Oamaru on Highway 1. Camp Iona has bunkrooms, a well equipped kitchen, a hall with an open fireplace, and good bathrooms with showers. You will need to bring your own food, plates, cutlery and sleeping bags. We will supply tea/coffee/Milo, milk and biscuits for morning teas and supper. You will also need to bring warm clothes to Camp Iona, and a telescope if applicable.

The fees are: Adults - $12 for one night; $24 for two nights. $30 for three nights. Secondary school teenagers $10 per night. Children aged 5-12 $6 per night. Pay your fees on-site at Camp Iona.

Those intending to come to the Herbert Astronomy Weekend are definitely encouraged to register online at http://www.treesandstars.com/herbert/ where more details about the Weekend can be viewed on the webpage.

There will be a few speakers. A data projector, screen and computer will be available.

If you wish to present a talk, or have any queries about the Herbert Astronomy Weekend, please contact Ross Dickie emai: This email address is being protected from spambots. You need JavaScript enabled to view it. or Euan Mason email: This email address is being protected from spambots. You need JavaScript enabled to view it.

4. Harry Williams Astrophotography Competition

This is the first announcement to all NZ astronomers, astrophotographers, photographers etc, that the Auckland Astronomical Society's 2011 Harry Williams Astrophotography Competition is now underway. This competition is open to all New Zealand residents, Astronomical Society members, clubs and groups. Remember, the prestigious Harry Williams Trophy is up for grabs.

There are 4 categories in this year's competition Deep Space Solar System Artistic/Mis Scientific You can download your entry form and competition details from the Auckland Astronomical Society Website. http://www.astronomy.org.nz Winners will be announced at the Burbidge Dinner in Auckland late October, 2011 (date yet to be advised). Competition closing date - Friday 23rd September 2011. Please send your entries by email (max 2MB per email) or copied onto CDROM/USB memory stick and posted with accompanying Entry Forms to; 2011 Harry William's Astrophotography Competition 2/24 Rapallo Place, Farm Cove, Pakuranga, Auckland 2012 Email: This email address is being protected from spambots. You need JavaScript enabled to view it. Subject Header: 2011 HW Astrophotography Competition

-- from a note by Jennie McCormick to the NZastronomers Yahoo group.

5. Mt John Community Nights

Mt John Observatory will be open to the public on the evenings of August 26 and 27, Friday and Saturday, from 6:30 to 9 pm. University of Canterbury telescopes, two 60-cm and the 1-metre, will be available for looking through. Earth and Sky Ltd (E&S) will have their 16-inch Meade and other telescopes open, also the Astrocafé. Parking is at the bottom of the hill. E&S buses will shuttle visitors from there to the top. Charges are $20 per adult; $5 for high school; primary and under 5's free. For weather enquiries phone 03 680 6960 or 03 680 6000. The Community Nights are a fund-raiser for Lake Tekapo School.

6. Gissy Gathering - Labour Weekend

John Drummond plans to hold another Gissy Gathering in October from Thursday 20th (Hawkes Bay Anniversary is on Friday) until Monday 24th (Labour Day) - people are welcome to leave Tuesday morning though.

This is like a micro-Stardate where there is imaging and observing at night and discussions about imaging/astronomy during the day using a data projector. The site offers a dark sky with a shop and pub down the road. There are number of telescopes to use for imaging - or to piggyback cameras on.

There is two acres for tenting and some sofas/floor space in the house for sleeping. The weekend costs $5 per person, per night to cover power and water. BYO food and drink.

If you want a fun, relaxing long-weekend observing with fellow astronomers then come along!!!

If you are keen on coming please contact This email address is being protected from spambots. You need JavaScript enabled to view it. . His home number is (06) 8627 557 and mobile is 0275 609 287.

There is a webpage about the weekend at - http://www.possumobservatory.co.nz/gissy_gathering-2011.htm

7. NACAA 2012

The 25th National Australian Convention of Amateur Astronomers (NACAA) meets in Brisbane over Easter, April 6-9. The meeting at the University of Queensland campus is hosted by the Astronomical Association of Queensland and supported by other astronomy clubs in South East Queensland.

The sixth Trans-Tasman Symposium on Occultations and the inaugural Variable Stars South Symposium will be held as part of the NACAA programme. Registrations for NACAA XXV will commence in late 2011.

For more information see http://www.nacaa.org.au Email enquiries to This email address is being protected from spambots. You need JavaScript enabled to view it. or write to P.O. Box 188, Plumpton, NSW 2761.

8. Third International Starlight Conference

The Third International Starlight Conference, subtitled "in defence of the quality of the night sky and the right to observe the stars" will be held on 11, 12 and 13 June 2012 at Lake Tekapo.

The conference will be the third in a series, following meetings in La Palma in April 2007 and on Fuerteventura in March 2009. It will address themes concerning o the defence of the quality of the night sky, o the right to observe the stars, the heritage of starlight, o the issues of light pollution, the protection of observatory sites, o the benefits of public outreach in astronomy and o the cultural aspects of visual astronomy. We will also discuss the concept, implementation and benefits of Starlight Reserves as a means of protecting the night sky, and the progress towards such reserves made in the document entitled "Heritage sites of astronomy and archaeoastronomy in the context of the UNESCO World Heritage Convention: a Thematic Study", which was produced under the aegis of the IAU (International Astronomical Union) and ICOMOS (International Council on Monuments and Sites), with Clive Ruggles and Michel Cotte as editors. The Thematic Study was presented to the World Heritage Convention in Brasilia in July 2010

In addition, several radio astronomers have pointed out that the issues of radio-frequency interference have much in common with issues of light pollution. We will therefore expand the topics under discussion to RFI and the development of radio-astronomy in New Zealand, especially the selection of radio-quiet sites. This is topical as New Zealand may participate with Australia in the Square Kilometre Array (SKA) radio- astronomy project.

For more information see www.starlight2012.org

9. RASNZ Conference 2012

The 2012 RASNZ conference, hosted by the Phoenix Astronomical Society will be held at Masterton on 15-17 June at the Copthorne Hotel & Resort, Solway Park, Masterton, shortly after the transit of Venus. Further details will appear on the RASNZ website when available.

10. Tom Gehrels

Dutch asteroid and comet discoverer and researcher Tom Gehrels died in Tuscon Arizona on 11 July 2011 aged 86. A graduate of Leiden University (1951), he earned a PhD from the University of Chicago in 1956 and joined the University of Arizona in 1961. His name is closely linked with the Pioneer 10 and 11 space-probes and the Spacewatch Program started in 1980.

Quote from a Radio Netherlands article (link below): [Journalist] Mr Schilling also recounted a conversation he had with Dr Gehrels about his work at on the Spacewatch Project. The journalist asked: "Suppose an asteroid that would hit Earth is discovered. What would you do?" Dr Gehrels replied, "Go out there and have a look, of course!"

Obituaries can be found at ... University of Arizona: http://uanews.org/node/40649 Sky & Telescope: http://www.skyandtelescope.com/news/125432648.html Radio Netherlands report: http://www.rnw.nl/africa/bulletin/dutch-american-astronomer-tom-gehrels- dies There is also a Wikipedia article at http://en.wikipedia.org/wiki/Tom_Gehrels

-- Thanks to Roland Idaczyk for this note.

11. Juno Spacecraft Off to Jupiter

NASA's solar-powered Juno spacecraft lifted off from Cape Canaveral Air Force Station on August 5 to begin a five-year journey to Jupiter.

Juno's detailed study of the largest planet in our solar system will help reveal Jupiter's origin and evolution. As the archetype of giant gas planets, Jupiter can help scientists understand the origin of our solar system and learn more about planetary systems around other stars.

Juno will cover the distance from Earth to the Moon, about 400,000 km in less than one day. It will take another five years 2,800 million km to complete the journey to Jupiter. The spacecraft will orbit the planet's poles 33 times and use its collection of eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere, and magnetosphere, and look for a potential solid planetary core.

With four large moons and many smaller moons, Jupiter forms its own miniature solar system. Its composition resembles a star's, and if it had been about 80 times more massive, the planet could have become a star instead.

'Jupiter is the Rosetta Stone of our solar system,' said Scott Bolton, Juno¹s principal investigator from the Southwest Research Institute in San Antonio. 'It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary -- to interpret what Jupiter has to say.'

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

-- from a NASA press release forwarded by Karen Pollard.

12. Kepler Studies Planetary Nebula

In a partnership between amateur and professional astronomers, the recent discovery of a dying star's last gasps could help resolve a decades-old debate among astronomers. That is, are stellar companions key to the formation and structure of planetary nebulae?

The discovery, by Austrian amateur astronomer Matthias Kronberger, is featured at an International Astronomical Union symposium on planetary nebulae held in Spain's Canary Islands on July. The research team's work features a striking image of the new nebula obtained with the Gemini Observatory.

Not coincidently, the location of the new nebula (named Kronberger 61, or Kn 61, after its discoverer) is within a relatively small patch of sky being intensely monitored by NASA's Kepler planet finding mission (http://kepler.nasa.gov/). Kepler's goal is to determine the frequency of Earth-sized planets around Sun-like stars. In the process, the effects of other close stellar and/or planetary companions are detectable.

NASA's Kepler mission monitors a 105 square degree portion of the sky near the northern constellation of Cygnus the Swan. Kepler's field-of-view is comparable to the area of your hand held at arm's length. The spacecraft continuously stares at more than 150,000 stars in the same patch of sky observing the changes in brightness. The presence of a companion can cause these brightness fluctuations through eclipses or tidal disruptions. However, most commonly in such binaries, the total amount of light received changes due to reflections from, and heating of, the companion by the star -- analogous to the Moon's phases.

'It is a gamble that possible companions, or even planets, can be found due to these usually small light variations, says George Jacoby of the Giant Magellan Telescope Organization and the Carnegie Observatories (Pasadena). 'However, with enough objects it becomes statistically very likely that we will uncover several where the geometries are favourable -- we are playing an odds game and it isn't yet known if Kn 61 will prove to have a companion.' Jacoby also serves as the Principal Investigator for a program to obtain follow-up observations of Kn 61's central star with Kepler.

To increase their odds, professional and amateur astronomers are working
as partners to comb through the entire Kepler field looking for planetary
nebula candidates. To date six have been found including this one by
Kronberger, a member of the amateur group called the 'Deep Sky Hunters.'
The group, dedicated to finding new objects in our galaxy and beyond, has
found two planetary nebulae in the Kepler field so far (including Kn 61)
and a possible third, which, according to Jacoby, 'are extremely rare and
each, a valuable gem.  Without this close collaboration with amateurs,
this discovery would probably not have been made before the end of the
Kepler mission. Professionals, using precious telescope time, aren't as
flexible as amateurs who did this using existing data and in their spare
time.

'Planetary nebulae present a profound mystery,' says Orsola De Marco of Macquarie University in Sydney. 'Some recent theories suggest that planetary nebulae form only in close binary or even planetary systems -- on the other hand, the conventional textbook explanation is that most stars, even solo stars like our Sun, will meet this fate. That might just be too simple.'

However, Jacoby points out that observations from the ground have yet to find a high percentage of binaries associated with planetary nebulae. 'This is quite likely due to our inability to detect these binaries from the ground and if so then Kepler is likely to push the debate strongly in one direction or the other.'

Planetary nebulae are common throughout our neighbourhood of the galaxy with over 3,000 known and identified. Likely the 'end of life' event for stars like our Sun, they form after nuclear fusion can no longer sustain the pressure of gravity in a geriatric star and it becomes unstable, pulsates and throws off a significant shell of gas from its outer layers. This expanding shell is what we see as a planetary nebula when its gas is ionized and glows due to the radiation still emitted by the central star. A key question with planetary nebulae is how companions (stars or even planets) around the central, primary star might impact the complex structures seen in many planetary nebulae. However, to date, a low percentage (about 20%) of these central stars have been found with companions. If this low fraction is due to the fact that the companions are relatively small or distant then current ground-based observations are simply not able to detect the companions -- in which case the space-based Kepler telescope will likely be able to fill this observational gap.

For background on the conference see http://www.iac.es/congreso/iaus283/

13. Active Black Hole Pair Discovered

A study using NASA's Swift satellite and the Chandra X-ray Observatory has found a second supersized black hole at the heart of an unusual galaxy already known to be sporting one.

The galaxy, which is known as Markarian 739 or NGC 3758, is 425 million light-years away in the constellation Leo. Only about 11,000 light-years separate the two cores, each of which contains a black hole gorging on infalling gas.

Most galaxies, including our own Milky Way, have at their centre a massive black hole millions of times the sun's mass. Some of them radiate billions of times as much energy as the sun. Astronomers refer to galaxy centres that radiate this way as active galactic nuclei (AGN). Yet as common as monster black holes are, only about one percent of them are currently powerful AGN. Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years of us.

Many scientists think that disruptive events like galaxy collisions trigger AGN to switch on by sending large amounts of gas toward the black hole. As the gas spirals inward, it becomes extremely hot and radiates huge amounts of energy.

Since 2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping high-energy X-ray sources all around the sky. The survey is sensitive to AGN up to 650 million light-years away and has uncovered dozens of previously unrecognized systems. Follow-up studies reveal that about a quarter of the Swift BAT AGN were either interacting or in close pairs, with perhaps 60 percent of them poised to merge in another billion years.

Swift's BAT instrument is scanning one-tenth of the sky at any given moment, providing a wide-angle view. Conversely, the X-ray telescope aboard the Chandra X-ray Observatory acts like a zoom lens and resolves details a hundred times smaller.

For decades, astronomers have known that the eastern nucleus of Markarian 739 contains a black hole that is actively accreting matter and generating prodigious energy. The Chandra study shows that its western neighbour is too. This makes the galaxy one of the nearest and clearest cases of a binary AGN.

The distance separating the two black holes is about a third of the distance separating the solar system from the centre of our own galaxy. The dual AGN of Markarian 739 is the second-closest known, both in terms of distance from one another and distance from Earth. However, another galaxy known as NGC 6240 holds both records.

The activity of Markarian 739 West was revealed only by high-resolution observations at high X-ray energies. It showed no evidence of being an AGN in visible, ultraviolet and radio observations.

The study was published in The Astrophysical Journal Letters.

For text, images, and video see: http://www.nasa.gov/mission_pages/swift/bursts/monster-black-holes.html

-- from a press release from NASA's Goddard Space Flight Centre, Greenbelt, Maryland, forwarded by Karen Pollard

14. Pluto's Fourth Moon

Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny new satellite, temporarily designated P4, was uncovered in a Hubble survey searching for rings around the dwarf planet.

The new moon is the smallest discovered around Pluto. It has an estimated diameter of 13 to 34 km. By comparison Charon, Pluto's largest moon, 1,043 km across, and the other moons, Nix and Hydra, are in the range of 32 to 113 km in diameter.

The finding is a result of ongoing work to support NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015. The mission is designed to provide new insights about worlds at the edge of our solar system. Hubble's mapping of Pluto's surface and discovery of its satellites have been invaluable to planning for New Horizons's close encounter.

The new moon is located between the orbits of Nix and Hydra, which Hubble discovered in 2005. Charon was discovered in 1978 by the U.S. Naval Observatory and first resolved using Hubble in 1990 as a separate body from Pluto. The dwarf planet¹s entire moon system is believed to have formed by a collision between Pluto and another planet- sized body early in the history of the solar system. The smashup flung material that coalesced into the family of satellites observed around Pluto.

Scientists believe material blasted off Pluto's moons by micrometeoroid impacts may form rings around the dwarf planet, but the Hubble photographs have not detected any so far.

P4 was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28. It was confirmed in subsequent Hubble pictures taken on July 3 and July 18. The moon was not seen in earlier Hubble images because the exposure times were shorter. There is a chance it appeared as a very faint smudge in 2006 images, but was overlooked because it was obscured.

-- from a NASA Press release forwarded by Karen Pollard.

15. Earth's First Trojan Asteroid Discovered

A Canadian team of astronomers have confirmed the existence of the first known Trojan Asteroid associated with Earth. The discovery is highlighted in the July 28, 2011, issue of Nature magazine. Trojan asteroids are objects in the same orbit as a main planet. The simplest keep around 60 degrees ahead or behind the planet, as measured from the sun. There are more complicated 'horseshoe Trojan' orbits that range back and forth along the main planet's orbit.

The Earth Trojan, called 2010 TK7, was first tentatively identified by the team from discovery observations made in October 2010. The actual discovery was made by NASA's Wide-field Infrared Survey Explorer (WISE) satellite. Follow-up observations were made with Mt John's 1-metre telescope, the 4-m reflector at Cerro Tololo and the 2-m Siding Spring- Faulkes Telescope South. The Canadian team confirmed the Trojan nature of the asteroid using new observations they obtained using the Canada-France- Hawaii Telescope (CFHT) in April 2011.

Previously, Trojans were known to exist associated with Jupiter, Neptune, and Mars. 2010 TK7 proves that they can also be found associated to Earth. How long can they keep their Trojan nature on Earth's orbit is still unclear, but 2010 TK7 is stable for at least ten thousand years. More Earth Trojans are likely to be found in the coming years, allowing for a better understanding of their dynamics and the characteristics of their population.

Images of 2010 TK7 observed at CFHT, with the corresponding astrometric data and links to images and animations, as well as a link to the Nature paper, can be found at: http://www.cfht.hawaii.edu/en/news/EarTro/

-- from a Canada-France-Hawaii Telescope Corporation press release forwarded by Karen Pollard.

16. 16-inch Dobsonian for Sale

Andrew Batten advises that he has a Meade Lightbridge 16-inch Dobsonian- mount telescope for sale. Among many extras it has an Argonavis go-to computer and a Televue eyepiece set. Contact details are: Mobile +64 21 329127; Phone + 64 9 4793945; Email This email address is being protected from spambots. You need JavaScript enabled to view it..

17. 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., R O'Keeffe, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697

18. 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. R O'Keeffe, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697

19. 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..

20. Quotes

"It is possible to store the mind with a million facts and still be entirely uneducated." -- Alec Bourne.

"There is nobody so irritating as somebody with less intelligence and more sense than we have." -- Don Herold.

"If it is true that our species is alone in the universe, then I'd have to say that the universe aimed rather low and settled for very little." -- George Carlin.

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


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