RASNZ Electronic Newsletter October 2015

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. The latest issue is below.

Email Newsletter Number 178

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. Astrophotography Weekend - Foxton Beach, Nov. 13-15
2. Central Star Party, Hawkes Bay -- Rescheduled to January 1-5
3. Stardate 2016 - Wairarapa, January 8-10
4. Stardate SI, Staveley, February 5-8
5. The Solar System in November
6. Variable Stars South 4th Symposium - March 24
7. 2016 Beatrice Hill Tinsley Lecturer
8. Ceres Bright Spots Seen in More Detail
9. Enceladus's Global Ocean
10. Perplexing Images of Pluto
11. The Sculptor Dwarf Galaxy's Evolution
12. Galaxy Cluster with Star-Burst Core
13. Massey University Introductory Astronomy Course
14. How to Join the RASNZ
15. Kingdon-Tomlinson Fund
16. Quote

1. Astrophotography Weekend - Foxton Beach, Nov. 13-15

The Horowhenua Astronomical Society is hosting its third annual astrophotography weekend. This will be held at the usual venue: Foxton Beach Bible Camp, Foxton Beach, Horowhenua, on the weekend of 13th-15th November 2015.

The weekend is open to everyone interested in astrophotography from beginners to advanced. Come along and share your knowledge, tips and experiences. It is a great venue for undertaking practical photography so feel free to bring as much imaging equipment as you like. If you have anything to sell this is a perfect opportunity. In addition to a range of interesting talks there will also be practical workshops lead by experts on processing software including Maxim DL, Pixinsight, Registax, ImagesPlus, and PT GUI PRO. Talks throughout the day. Places are limited and are running out so please book ASAP by going to the web address: www.horoastronomy.org.nz or email This email address is being protected from spambots. You need JavaScript enabled to view it.

-- Stephen Chadwick

2. Central Star Party, Hawkes Bay -- Rescheduled to January 1-5

The Inter Society Astronomical Advancement Committee have rescheduled the dates for the Central Star Party from the 7-11 Jan 2016 to Friday 1st - Tuesday 5th (am) January 2016. The official opening will be Friday 1st January at 7:00pm. With New Year's Day being a holiday, hopefully people can get to Tuki Tuki Camp, Hawkes Bay during the day. For more details see http://www.censtar.party/-- John Drummond.

For those into long-term planning John advises that the 2017 and 2018 Central Star Parties will be: On Thurs 19 - Mon 23rd January 2017 (we leave the morning of Tues 24th January 2017). The last quarter moon is Fri 20th. On Thurs 18th - Tues 23rd (am) January 2018. New Moon is Wed 17th January 2018.

3. Stardate 2016 - Wairarapa, January 8-10

Stardate 2016 will be held at Stonehenge Aotearoa, near Carterton in the Wairarapa. This is the same venue where Stardate was held last year. The camp site will again be in the field behind the Visitors´ Centre. The main part of the programme will be based around the 8th, 9th and 10th of January but attendees will be able to arrive earlier by arrangement.

The facilities are still basic but we hope to add to these with time. Camping is the order of the day. Attendees will be able to use the toilets in the AV centre and basic showers will be erected. We do not have bunk rooms, however full details of local accommodation are available here: http://www.stonehenge-aotearoa.co.nz/Tours++Treks/Booking+Your+Visit/Carterton+Accommodation.html

Stonehenge Aotearoa will be in full operation during the period from 10 am to 4 pm. A free guided tour will be arranged for attendees during Stardate and some observing may take place from the henge after opening hours (depending on bookings).

Registration costs will be very similar to or the same as last year: $23 for adults; children (pre-teens) accompanied by parents free (these costs have yet to be confirmed by the Phoenix Council). We will arrange for a mobile caterer to visit the site, so that at least one meal during Stardate can be purchased on site.

This is an attractive site with good swimming holes in the Ruamahanga River just down the road. The wine growing areas of Martinborough, Gladstone and Masterton are within 30 minutes. There is a thriving tourist industry with many activities and venues available within the same distance.

If you are interested in attending Stardate 2016 please send an expression of interest to Kay Leather: This email address is being protected from spambots. You need JavaScript enabled to view it. with Stardate in the subject line.

We want to confirm programme details as quickly as possible and we want to put together a varied and interesting programme. If anyone has a presentation that they are prepared to make at Stardate 2016, please let Richard (This email address is being protected from spambots. You need JavaScript enabled to view it.) or Kay (This email address is being protected from spambots. You need JavaScript enabled to view it.) know as many details as you can. Hopefully, we can have a preliminary programme in the November newsletter.

-- Kay Leather.

4. Stardate SI, Staveley, February 5-8

Stardate SI will be held at the hostel and camp at Staveley between Friday February 5th and Monday February 8th, 2016. Come and join us for this magnificent celebration of astronomy, science, and the cosmos at large. For details see http://www.treesandstars.com/stardate/Link to the Facebook event for Stardate SI. If you are attending, then use this link to choose which DVDs you'd like to watch in the (we hope) unlikely event of cloudy weather

We look forward to seeing you there.

-- Euan Mason

5. The Solar System in November

Dates and times shown are NZDT (UT + 13 Hours) unless otherwise stated. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in november

                         November  1  NZDT             November 30  NZDT
               morning       evening          morning      evening
      SUN:  rise:  6.06am,  set: 8.03pm    rise: 5.40am,  set: 8.38pm
Twilights
 Civil:    starts: 5.39am, ends: 8.31pm  starts: 5.10am, ends: 9.09pm
 Nautical: starts: 5.03am, ends: 9.07pm  starts: 4.29am, ends: 9.50pm 
 Astro:    starts: 4.24am, ends: 9.46pm  starts: 3.41am, ends:10.38pm

November PHASES OF THE MOON (times as shown by GUIDE)

          Last quarter:  November  4 at  1.24 am (Nov  3, 12:24 UT)
  New moon:      November 12 at  6.47 am (Nov 11, 17:47 UT)
  First quarter: November 19 at  7.27 pm (06:27 UT) 
  Full moon:     November 26 at 11.44 am (Nov 25, 22:44 UT)

The planets in november

Saturn will be the only naked eye evening planet during October, and that only for the first part of the month. There is more interest in the morning with Venus, Mars and Jupiter forming a loose cluster in the dawn sky. Mercury is not likely to be visible.

MERCURY is at superior conjunction on the far side of the Sun on the night November 17/18 NZ time. The planet starts November as a nominal morning object but rises only 18 minutes before the Sun. After conjunction the planet becomes an evening object. By November 30 it will set 40 minutes later than the Sun, but is not likely to be visible in the evening twilight.

At this conjunction, Mercury passes behind the Sun as "seen" from the Earth. The planet moves behind the Sun at about 9.25 pm, an hour after sunset, and doesn't emerge again until about 6.29 am on the 18th, 40 minutes after sunrise the following morning. (Times are as shown by GUIDE 9). So Mercury is behind the Sun for about 9 hours. At conjunction the planet will be 216 million km (1.446 AU) from the Earth and 0.457 AU (68 million km) beyond the Sun.

VENUS, MARS and JUPITER in the morning sky during November.

The three planets will start the month as a close group in Leo, although Venus and Mars both move into Virgo within a day. On the 1st Jupiter is about 6° from the other two planets.

Venus and Mars start October close together, within a degree of each other for the first 5 days of the month. On the morning of the 3rd they will be three-quarters of a degree apart with Mars below Venus. The following morning, the two will be very slightly closer, with Mars now to the lower left of Venus.

To see the pairing it will be necessary to look for the planets at least half an hour before sunrise. By then Mars may be lost to naked eye view in the brightening twilight, although Venus should still be easily seen. Binoculars will then readily show Mars, magnitude 1.7. Obviously viewing earlier will make it easier to see Mars, but the two will be low: they rise a little short of two hours before the Sun.

The crescent moon joins the group of planets on the 7th when it will be 2° to the right of Jupiter. By the following morning the moon will have moved past Mars to be 2° to the right of Venus.

For the rest of October, Venus and Mars move across Virgo, with slower moving Mars dropping behind Venus. As a result by the end of October Mars will be higher in the sky than Venus, rising two and a half hours before the Sun while Venus still rises just under two hours before it. Jupiter will be higher still rising over 3 hours before the Sun.

SATURN is heading for its conjunction with the Sun at the end of November. It starts the month setting two hours after the Sun. On the 1st, an hour after sunset, Saturn will be visible 10° up and a good 15° round to the south of due west. Antares will be some 8.5° above the planet, the constellation Scorpius appearing as an upright curled fern with Saturn at its root. During the following nights, Saturn and the constellation will get steadily lower, so that by mid-month it will be lost in the evening twilight.

On the 13th the moon, as a very thin crescent, will be just over 4° to the right of Saturn, providing a possible last chance to find Saturn, or maybe an opportunity to find the crescent moon about 36 hours after new. 40 minutes after sunset with the Sun some 8° below the horizon, Saturn and the moon will be less than 4° above the horizon.

At conjunction on the 30th, Saturn will be 11AU, 1644 million km, from the Earth and 10AU beyond the Sun. As "seen" from the Earth, Saturn will pass 1.5° north of the Sun.

Outer planets

URANUS remains in Pisces during November at magnitude 5.7. Opposition was on October 12, so the planet will be visible throughout the evening, setting several hours after midnight.

There is yet another occultation of the Uranus by the moon on November 23. It occurs in the morning after Uranus sets and is visible at night from the south Indian and Southern Oceans to the west of Australia.

NEPTUNE is also an evening object throughout November, setting after midnight but about 90 minutes before Uranus. The planet is at magnitude 7.9 and is in Aquarius throughout the month.

PLUTO continues to be in Sagittarius throughout November at magnitude 14.4.

BRIGHTER ASTEROIDS: (1) Ceres starts November in Sagittarius and ends in Capricornus, having crossed a corner of Mica between the 7th and 17th. The asteroid is an evening object setting after midnight, its magnitude dimming slightly from 9.1 to 9.3

(4) Vesta is in Cetus throughout November, its magnitude ranging from 6.9 to 7.5. The asteroid is stationary mid month.

(15) Eunomia remains in Pegasus during November its magnitude varying from 8.4 to 8.9. Also an evening object, it is stationary on the 7th.

(29) Amphitrite is in Pisces all month, its magnitude fading from 8.9 to 9.6. It will be just over 1° north of the mag 3.6 star eta Psc mid- month. It sets well after midnight all month.

(192) Nausikaa is in Perseus and rather low in NZ skies. It starts November at magnitude 9.4 a little over a degree from the magnitude 2.9 star zeta Per. During November Nausikaa brightens to magnitude 9.0 at opposition on the 17th. By the end of November it will have faded again to 9.3. The asteroid rises about 11 pm on the 1st and at sunset on the 30th.

-- Brian Loader

6. Variable Stars South 4th Symposium - March 24

The National Australian Convention of Amateur Astronomers (NACAA) will hold its 27th meeting in Sydney over the 2016 Easter long weekend. NACAA will be hosted by the Sutherland Astronomical Society Inc, and will be held at the new Law Annexe at the University of NSW. Details of accommodation and the like will be posted to the NACAA website soon.

While details of the programme are still being finalised, it is intended that Variable Stars South (VSS) will hold its 4th Symposium on the Friday (March 25 - Good Friday).

Members of the VSS community are invited to submit papers and posters via the NACAA website (http://www.nacaa.org.au/2016/proposal) for either the Symposium (most likely focused on specific research reports and the like) or the main NACAA meeting (more general variable star observing subjects).

More details of the event can be found at the NACAA website, and if you register your interest you will receive alerts as they are posted.

-- David O´Driscoll, Programme Committee Chair, NACAA 2016 & VSS Webmaster

7. 2016 Beatrice Hill Tinsley Lecturer

The RASNZ Lecture Trust is pleased to announce that the 2016 Beatrice Hill Tinsley lecturer will be Dr Michael Person. Dr Person is a research scientist at the Massachusetts Institute of Technology Planetary Astronomy Laboratory. His interests include observational astronomy, focusing on the techniques needed to observe stellar occultations, eclipses, and transits; and identifying and characterizing the atmospheres, compositions, and figures of solar system bodies. Dr Person has a special interest in distant solar system bodies, specifically Triton, Pluto, and Kuiper Belt Objects and so the lectures will focus on Pluto and the recent New Horizons mission. The lecture tour will take place during July-August 2016. Expressions of interest are invited from Affiliated Societies to host one of the 2016 BHT lectures. Societies have until the end of October to contact the RASNZ Lecture Trust at This email address is being protected from spambots. You need JavaScript enabled to view it. to register their interest.

-- Gary Sparks, Secretary, RASNZ Lecture Trust.

8. Ceres Bright Spots Seen in More Detail

The brightest spots on the dwarf planet Ceres gleam with mystery in new views delivered by NASA's Dawn spacecraft. These closest-yet views of Occator crater, with a resolution of 140 meters per pixel, give scientists a deeper perspective on these very unusual features.

The individual animations are available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19890 http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19891

The new up-close view of Occator crater from Dawn's current vantage point reveals better-defined shapes of the brightest, central spot and features on the crater floor. Because these spots are so much brighter than the rest of Ceres' surface, the Dawn team combined two different images into a single composite view -- one properly exposed for the bright spots, and one for the surrounding surface.

Scientists also have produced animations that provide a virtual fly- around of the crater, including a colourful topographic map.

Dawn scientists note the rim of Occator crater is almost vertical in some places, where it rises steeply for nearly 2 km.

Views from Dawn's current orbit, taken at an altitude of 1,470 km, have about three times better resolution than the images the spacecraft delivered from its previous orbit in June, and nearly 10 times better than in the spacecraft's first orbit at Ceres in April and May.

-- From a NASA JPL press release forwarded by Karen Pollard.

9. Enceladus's Global Ocean

A global ocean lies beneath the icy crust of Saturn´s geologically active moon Enceladus, according to new research using data from NASA´s Cassini mission.

Researchers found the magnitude of the moon´s very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.

The finding implies the fine spray of water vapour, icy particles and simple organic molecules Cassini has observed coming from fractures near the moon´s south pole is being fed by this vast liquid water reservoir. The research has been presented in a paper published online in the journal Icarus.

Previous analysis of Cassini data suggested the presence of a lens- shaped body of water, or sea, underlying the moon´s south polar region. However, gravity data collected during the spacecraft´s several close passes over the south polar region lent support to the possibility the sea might be global. The new results -- derived using an independent line of evidence based on Cassini´s images -- confirm this to be the case.

Cassini scientists analysed more than seven years´ worth of images of Enceladus taken by the spacecraft, which has been orbiting Saturn since mid-2004. They carefully mapped the positions of features on Enceladus -- mostly craters -- across hundreds of images, in order to measure changes in the moon´s rotation with extreme precision.

As a result, they found Enceladus has a tiny, but measurable wobble as it orbits Saturn. Because the icy moon is not perfectly spherical -- and because it goes slightly faster and slower during different portions of its orbit around Saturn -- the giant planet subtly rocks Enceladus back and forth as it rotates.

The team plugged their measurement of the wobble, called a libration, into different models for how Enceladus might be arranged on the inside, including ones in which the moon was frozen from surface to core.

If the surface and core are rigidly connected, then the core would provide so much dead weight the wobble would be far smaller than is observed. This proves that there must be a global layer of liquid separating the surface from the core.

The mechanisms that might have prevented Enceladus´ ocean from freezing remain a mystery. Among ideas for future study is the surprising possibility that tidal forces due to Saturn´s gravity could be generating much more heat within Enceladus than previously thought.

The unfolding story of Enceladus has been one of the great triumphs of Cassini´s long mission at Saturn. Scientists first detected signs of the moon´s icy plume in early 2005, and followed up with a series of discoveries about the material gushing from warm fractures near its south pole. They announced strong evidence for a regional sea in 2014, and more recently, in 2015, they shared results that suggest hydrothermal activity is taking place on the ocean floor.

Cassini is scheduled to make a close flyby of Enceladus on Oct. 28, in the mission´s deepest-ever dive through the moon´s active plume of icy material. The spacecraft will pass a mere 49 km above the moon´s surface.

For the original text & Images see: http://www.ciclops.org/view.php?id=8199 http://www.jpl.nasa.gov/news/news.php?release=2015-298

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

10. Perplexing Images of Pluto

The newest high-resolution images of Pluto from NASA´s New Horizons are both dazzling and mystifying, revealing a multitude of previously unseen topographic and compositional details.

One image, showing an area on Pluto´s best-mapped hemisphere near the line that separates day from night, captures a vast rippling landscape of strange, aligned linear ridges that has astonished New Horizons team members. It may have been made by some combination of internal tectonic forces and ice sublimation driven by Pluto´s faint sunlight.

The spacecraft also captured the highest-resolution colour view yet of Pluto -- along with detailed spectral maps and other high-resolution images. The new "extended colour" view of Pluto -- taken by New Horizons´ wide-angle Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14 and downlinked to Earth on Sept. 19 -- shows the extraordinarily rich colour palette of Pluto.

Additionally, a high-resolution swath across Pluto taken by New Horizons´ narrow-angle Long Range Reconnaissance Imager (LORRI) on July 14, and downlinked on Sept. 20, homes in on details of Pluto´s geology. These images, the highest-resolution yet available of Pluto, reveal features that resemble dunes, the older shoreline of a shrinking glacial ice lake, and fractured, angular, jammed-together water ice mountains with sheer cliffs.

This closer look at the smooth, bright surface of the informally named Sputnik Planum shows that it is actually pockmarked by dense patterns of pits, low ridges and scalloped terrain. Dunes of bright volatile ice particles are a possible explanation, mission scientists say, but the ices of Sputnik may be especially susceptible to sublimation and formation of such corrugated ground.

Beyond the new images, new compositional information comes from a just- obtained map of methane ice across part of Pluto´s surface that reveals striking contrasts: Sputnik Planum has abundant methane while the region informally named Cthulhu Regio shows none, apart from a few isolated ridges and crater rims. Mountains along the west flank of Sputnik lack methane as well.

The distribution of methane across the surface is anything but simple, with higher concentrations on bright plains and crater rims, but usually none in the centres of craters or darker regions. Outside of Sputnik Planum, methane ice appears to favour brighter areas, but scientists aren´t sure if that is because methane is more likely to condense there or that its condensation is what brightens those regions.

For the full text & Images see: http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150924

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

11. The Sculptor Dwarf Galaxy's Evolution

As part of its public image display the European Southern Observatory (ESO) has published an image of the Sculptor Dwarf Galaxy. The photo was obtained with the Wide Field Imager camera, installed on the 2.2- metre MPG/ESO telescope at ESO´s La Silla Observatory.

The Sculptor Dwarf Galaxy is a close neighbour of our galaxy, the Milky Way. Despite their close proximity, both galaxies have very distinct histories and characters. The Sculptor Dwarf Galaxy is much smaller and older than the Milky Way, making it a valuable subject for studying both star and galaxy formation in the early Universe. However, due to its faintness, studying this object is no easy task

The Sculptor Dwarf Galaxy - also known as the Sculptor Dwarf Elliptical or the Sculptor Dwarf Spheroidal - is a dwarf spheroidal galaxy, and is one of the fourteen known satellite galaxies orbiting the Milky Way. These galactic hitchhikers are located close by in the Milky Way´s extensive halo, a spherical region extending far beyond our galaxy´s spiral arms. As indicated by its name, this galaxy is located in the southern constellation of Sculptor and lies about 280 000 light-years away from Earth. Despite its proximity, the galaxy was only discovered in 1937, as its stars are faint and spread thinly across the sky. (This faint galaxy should not be confused with the much brighter Sculptor Galaxy, NGC 253, in the same constellation.)

Although difficult to pick out, the Sculptor Dwarf Galaxy was among the first faint dwarf galaxies found orbiting the Milky Way. The tiny galaxy´s shape intrigued astronomers at the time of its discovery, but nowadays dwarf spheroidal galaxies play a more important role in allowing astronomers to dig deeply into the Universe´s past.

The Milky Way, like all large galaxies, is thought to have formed from the build-up of smaller galaxies during the early days of the Universe. If some of these small galaxies still remain today, they should now contain many extremely old stars. The Sculptor Dwarf Galaxy fits the bill as a primordial galaxy, thanks to a large number of ancient stars, visible in this image.

Astronomers can determine the age of stars in the galaxy because their light carries the signatures of only a small quantity of heavy chemical elements. These heavy elements accumulate in galaxies with successive generations of stars. A low level of heavy elements thus indicates that the stars in the Sculptor Dwarf Galaxy are old.

This quantity of old stars makes the Sculptor Dwarf Galaxy a prime target for studying the earliest periods of star formation. In a recent study, astronomers combined all the data available for the galaxy to create the most accurate star formation history ever determined for a dwarf spheroidal galaxy. This analysis revealed two distinct groups of stars in the galaxy. The first, predominant group is the older population, which is lacking in heavier elements. The second, smaller population, in contrast, is rich with heavy elements. The youthful stellar population is concentrated toward the galaxy´s core.

The stars within dwarf galaxies like the Sculptor Dwarf Galaxy can exhibit complex star formation histories. But as most of these dwarf galaxies´ stars have been isolated from each other and have not interacted for billions of years, each collection of stars has charted its own evolutionary course. Studying the similarities in dwarf galaxies´ histories, and explaining the occasional outliers, will help to explain the development of all galaxies, from the most unassuming dwarf to the grandest spirals. There is indeed much for astronomers to learn from the Milky Way´s shy neighbours.

To see the Sculptor Dwarf Galaxy image go to http://www.eso.org/public/images/archive/search/?adv=&facility=15 and enter'eso1536' into the search window.

-- From an ESO press release forwarded by Karen Pollard.

12. Galaxy Cluster with Star-Burst Core

An international team of astronomers has discovered a gargantuan galaxy cluster with a core bursting with new stars - an incredibly rare find. The discovery, made with the help of the NASA/ESA Hubble Space Telescope, is the first to show that gigantic galaxies at the centres of massive clusters can grow significantly by feeding off gas stolen from other galaxies.

Galaxy clusters are vast families of galaxies bound together by gravity. Our own galaxy, the Milky Way resides within a small galaxy group known as the Local Group, which itself is a member of the massive Laniakea supercluster.

Galaxies at the centres of clusters are usually made of stellar fossils - old, red or dead stars. However, astronomers have now discovered a giant galaxy at the heart of a cluster named SpARCS1049+56 that seems to be bucking the trend, instead forming new stars at an incredible rate. It appears that the giant galaxy has recently collided with, and merged with, a smaller galaxy rich in gas. The gas is now forming into stars at the rate of 800 new stars per year. The Milky Way forms two stars per year at most!

The galaxy was initially discovered using NASA´s Spitzer Space Telescope and the Canada-France-Hawaii Telescope, located on Mauna Kea in Hawai`i and confirmed using the W.M. Keck Observatory, also on Mauna Kea. Follow-up observations using the NASA/ESA Hubble Space Telescope allowed the astronomers to explore the galaxy´s activity.

The Spitzer data showed us a truly enormous amount of star formation in the heart of this cluster, something that has rarely been seen before, and certainly not in a cluster this distant.

The SpARCS1049+56 cluster is so far away that its light took 9.8 billion years to reach us. It houses at least 27 galaxies and has a combined mass equal to 400 trillion Suns. It is a truly unique cluster in one aspect - its vibrant heart of new stars.

Spitzer picks up infrared light, so it can detect the warm glow of hidden, dusty regions of star-birth. Follow-up studies with Hubble in visible light helped to pinpoint what was fuelling the new star formation.

Building on their other observations the team used Hubble to explore the galaxy in depth. What they found was a "train wreck" of a merger at the centre of this cluster. The images showed features that looked like beads on a string."

Beads on a string are a tell-tale signs of something known as a "wet merger". Wet mergers occur when gas-rich galaxies collide. The gas is then converted quickly into new stars. "Dry mergers" involve the coming together of two galaxies lacking in gas. The two just mix their existing stars, rather than causing the birth of any new ones.

The new discovery is one of the first known cases of a wet merger at the core of a galaxy cluster. Hubble had previously discovered another closer galaxy cluster containing a wet merger, but it was not forming stars as vigorously. Other galaxy clusters grow in mass through dry mergers or by siphoning gas towards their centres. For example, the mega galaxy cluster known as the Phoenix Cluster grows in size by sipping off gas that flows into its centre.

The astronomers now aim to explore how common this type of growth mechanism is in galaxy clusters. Are there other "messy eaters" out there similar to SpARCS1049+56, which also munch on gas-rich galaxies? SpARCS1049+56 may be an outlier - or it may represent an early time in our Universe when messy eating was the norm.

These new results are presented in a paper entitled "An Extreme Starburst In The Core Of a Rich Galaxy Cluster At z = 1.7", published in The Astrophysical Journal on 21 August 2015.

For more see: https://www.spacetelescope.org/videos/heic1414a/http://www.spacetelescope.org/static/archives/releases/science_papers/h eic1519a.pdf

-- From a press release forwarded by Karen Pollard.

13. Massey University Introductory Astronomy Course

In the second semester of 2015 (13 July 2015 - 11 November 2015) Massey University´s Manawatu campus has been running an introductory astronomy paper at first year level. The paper is being run in conjunction with an existing paper at Massey´s Albany campus, and is taught by Jeremy Moss (who is also the President of the Palmerston North Astronomical Society) and Stephen Chadwick (also President of the Horowhenua Astronomical Society). The paper includes a practical observing component as part of the assessment, and it covers the following topics: the Solar System and astronomical history; the Sun and stars; galaxies and cosmology.

The paper is designed to cover the basics of astronomy for non-science students, but it also links in with Massey´s second year paper in Special Relativity and Cosmology.

It will also be run in the second semester of 2016, and there are plans For extending it to an extramural option in the future. For more details, please contact Jeremy Moss at This email address is being protected from spambots. You need JavaScript enabled to view it.

14. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2015 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

15. 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. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 November 2015. 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.

16. Quote

"In 'Birth of a Rocket' [Scientific American, June 2015, p.44], David H. Freedman reports that 'the real justification for human spaceflight is to take steps toward expanding the human race's stomping grounds.' Does he mean for a few elite astronauts or humanity generally? The former may be achievable - but why bother? The latter seems just shy of delusional. Either way, wouldn't it be more sensible to take the up to $1 trillion that a trip to Mars might cost and use it to prevent the collapse of liveable conditions on Earth?" -- Evan Fales.

Alan Gilmore Phone: 03 680 6817 P.O. Box 57 This email address is being protected from spambots. You need JavaScript enabled to view it. Lake Tekapo 7945 New Zealand

. Royal Astronomical Society of New Zealand . Email Newsletter Number 178, 20 October 2015

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. Astrophotography Weekend - Foxton Beach, Nov. 13-15

2. Central Star Party, Hawkes Bay -- Rescheduled to January 1-5 3. Stardate 2016 - Wairarapa, January 8-10 4. Stardate SI, Staveley, February 5-8 5. The Solar System in November 6. Variable Stars South 4th Symposium - March 24 7. 2016 Beatrice Hill Tinsley Lecturer 8. Ceres Bright Spots Seen in More Detail 9. Enceladus's Global Ocean 10. Perplexing Images of Pluto 11. The Sculptor Dwarf Galaxy's Evolution 12. Galaxy Cluster with Star-Burst Core 13. Massey University Introductory Astronomy Course 14. How to Join the RASNZ 15. Kingdon-Tomlinson Fund 16. Quote

1. Astrophotography Weekend - Foxton Beach, Nov. 13-15

The Horowhenua Astronomical Society is hosting its third annual astrophotography weekend. This will be held at the usual venue: Foxton Beach Bible Camp, Foxton Beach, Horowhenua, on the weekend of 13th-15th November 2015.

The weekend is open to everyone interested in astrophotography from beginners to advanced. Come along and share your knowledge, tips and experiences. It is a great venue for undertaking practical photography so feel free to bring as much imaging equipment as you like. If you have anything to sell this is a perfect opportunity. In addition to a range of interesting talks there will also be practical workshops lead by experts on processing software including Maxim DL, Pixinsight, Registax, ImagesPlus, and PT GUI PRO. Talks throughout the day. Places are limited and are running out so please book ASAP by going to the web address: www.horoastronomy.org.nz or email This email address is being protected from spambots. You need JavaScript enabled to view it.

-- Stephen Chadwick

2. Central Star Party, Hawkes Bay -- Rescheduled to January 1-5

The Inter Society Astronomical Advancement Committee have rescheduled the dates for the Central Star Party from the 7-11 Jan 2016 to Friday 1st - Tuesday 5th (am) January 2016. The official opening will be Friday 1st January at 7:00pm. With New Year's Day being a holiday, hopefully people can get to Tuki Tuki Camp, Hawkes Bay during the day. For more details see http://www.censtar.party/-- John Drummond.

For those into long-term planning John advises that the 2017 and 2018 Central Star Parties will be: On Thurs 19 - Mon 23rd January 2017 (we leave the morning of Tues 24th January 2017). The last quarter moon is Fri 20th. On Thurs 18th - Tues 23rd (am) January 2018. New Moon is Wed 17th January 2018.

3. Stardate 2016 - Wairarapa, January 8-10

Stardate 2016 will be held at Stonehenge Aotearoa, near Carterton in the Wairarapa. This is the same venue where Stardate was held last year. The camp site will again be in the field behind the Visitors´ Centre. The main part of the programme will be based around the 8th, 9th and 10th of January but attendees will be able to arrive earlier by arrangement.

The facilities are still basic but we hope to add to these with time. Camping is the order of the day. Attendees will be able to use the toilets in the AV centre and basic showers will be erected. We do not have bunk rooms, however full details of local accommodation are available here: http://www.stonehenge-aotearoa.co.nz/Tours++Treks/Booking+Your+Visit/Carterton+Accommodation.html

Stonehenge Aotearoa will be in full operation during the period from 10 am to 4 pm. A free guided tour will be arranged for attendees during Stardate and some observing may take place from the henge after opening hours (depending on bookings).

Registration costs will be very similar to or the same as last year: $23 for adults; children (pre-teens) accompanied by parents free (these costs have yet to be confirmed by the Phoenix Council). We will arrange for a mobile caterer to visit the site, so that at least one meal during Stardate can be purchased on site.

This is an attractive site with good swimming holes in the Ruamahanga River just down the road. The wine growing areas of Martinborough, Gladstone and Masterton are within 30 minutes. There is a thriving tourist industry with many activities and venues available within the same distance.

If you are interested in attending Stardate 2016 please send an expression of interest to Kay Leather: This email address is being protected from spambots. You need JavaScript enabled to view it. with Stardate in the subject line.

We want to confirm programme details as quickly as possible and we want to put together a varied and interesting programme. If anyone has a presentation that they are prepared to make at Stardate 2016, please let Richard (This email address is being protected from spambots. You need JavaScript enabled to view it.) or Kay (This email address is being protected from spambots. You need JavaScript enabled to view it.) know as many details as you can. Hopefully, we can have a preliminary programme in the November newsletter.

-- Kay Leather.

4. Stardate SI, Staveley, February 5-8

Stardate SI will be held at the hostel and camp at Staveley between Friday February 5th and Monday February 8th, 2016. Come and join us for this magnificent celebration of astronomy, science, and the cosmos at large. For details see http://www.treesandstars.com/stardate/Link to the Facebook event for Stardate SI. If you are attending, then use this link to choose which DVDs you'd like to watch in the (we hope) unlikely event of cloudy weather

We look forward to seeing you there.

-- Euan Mason

5. The Solar System in November

Dates and times shown are NZDT (UT + 13 Hours) unless otherwise stated. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in november

                         November  1  NZDT             November 30  NZDT
               morning       evening          morning      evening
      SUN:  rise:  6.06am,  set: 8.03pm    rise: 5.40am,  set: 8.38pm
Twilights
 Civil:    starts: 5.39am, ends: 8.31pm  starts: 5.10am, ends: 9.09pm
 Nautical: starts: 5.03am, ends: 9.07pm  starts: 4.29am, ends: 9.50pm 
 Astro:    starts: 4.24am, ends: 9.46pm  starts: 3.41am, ends:10.38pm

November PHASES OF THE MOON (times as shown by GUIDE)

          Last quarter:  November  4 at  1.24 am (Nov  3, 12:24 UT)
  New moon:      November 12 at  6.47 am (Nov 11, 17:47 UT)
  First quarter: November 19 at  7.27 pm (06:27 UT) 
  Full moon:     November 26 at 11.44 am (Nov 25, 22:44 UT)

The planets in november

Saturn will be the only naked eye evening planet during October, and that only for the first part of the month. There is more interest in the morning with Venus, Mars and Jupiter forming a loose cluster in the dawn sky. Mercury is not likely to be visible.

MERCURY is at superior conjunction on the far side of the Sun on the night November 17/18 NZ time. The planet starts November as a nominal morning object but rises only 18 minutes before the Sun. After conjunction the planet becomes an evening object. By November 30 it will set 40 minutes later than the Sun, but is not likely to be visible in the evening twilight.

At this conjunction, Mercury passes behind the Sun as "seen" from the Earth. The planet moves behind the Sun at about 9.25 pm, an hour after sunset, and doesn't emerge again until about 6.29 am on the 18th, 40 minutes after sunrise the following morning. (Times are as shown by GUIDE 9). So Mercury is behind the Sun for about 9 hours. At conjunction the planet will be 216 million km (1.446 AU) from the Earth and 0.457 AU (68 million km) beyond the Sun.

VENUS, MARS and JUPITER in the morning sky during November.

The three planets will start the month as a close group in Leo, although Venus and Mars both move into Virgo within a day. On the 1st Jupiter is about 6° from the other two planets.

Venus and Mars start October close together, within a degree of each other for the first 5 days of the month. On the morning of the 3rd they will be three-quarters of a degree apart with Mars below Venus. The following morning, the two will be very slightly closer, with Mars now to the lower left of Venus.

To see the pairing it will be necessary to look for the planets at least half an hour before sunrise. By then Mars may be lost to naked eye view in the brightening twilight, although Venus should still be easily seen. Binoculars will then readily show Mars, magnitude 1.7. Obviously viewing earlier will make it easier to see Mars, but the two will be low: they rise a little short of two hours before the Sun.

The crescent moon joins the group of planets on the 7th when it will be 2° to the right of Jupiter. By the following morning the moon will have moved past Mars to be 2° to the right of Venus.

For the rest of October, Venus and Mars move across Virgo, with slower moving Mars dropping behind Venus. As a result by the end of October Mars will be higher in the sky than Venus, rising two and a half hours before the Sun while Venus still rises just under two hours before it. Jupiter will be higher still rising over 3 hours before the Sun.

SATURN is heading for its conjunction with the Sun at the end of November. It starts the month setting two hours after the Sun. On the 1st, an hour after sunset, Saturn will be visible 10° up and a good 15° round to the south of due west. Antares will be some 8.5° above the planet, the constellation Scorpius appearing as an upright curled fern with Saturn at its root. During the following nights, Saturn and the constellation will get steadily lower, so that by mid-month it will be lost in the evening twilight.

On the 13th the moon, as a very thin crescent, will be just over 4° to the right of Saturn, providing a possible last chance to find Saturn, or maybe an opportunity to find the crescent moon about 36 hours after new. 40 minutes after sunset with the Sun some 8° below the horizon, Saturn and the moon will be less than 4° above the horizon.

At conjunction on the 30th, Saturn will be 11AU, 1644 million km, from the Earth and 10AU beyond the Sun. As "seen" from the Earth, Saturn will pass 1.5° north of the Sun.

Outer planets

URANUS remains in Pisces during November at magnitude 5.7. Opposition was on October 12, so the planet will be visible throughout the evening, setting several hours after midnight.

There is yet another occultation of the Uranus by the moon on November 23. It occurs in the morning after Uranus sets and is visible at night from the south Indian and Southern Oceans to the west of Australia.

NEPTUNE is also an evening object throughout November, setting after midnight but about 90 minutes before Uranus. The planet is at magnitude 7.9 and is in Aquarius throughout the month.

PLUTO continues to be in Sagittarius throughout November at magnitude 14.4.

BRIGHTER ASTEROIDS: (1) Ceres starts November in Sagittarius and ends in Capricornus, having crossed a corner of Mica between the 7th and 17th. The asteroid is an evening object setting after midnight, its magnitude dimming slightly from 9.1 to 9.3

(4) Vesta is in Cetus throughout November, its magnitude ranging from 6.9 to 7.5. The asteroid is stationary mid month.

(15) Eunomia remains in Pegasus during November its magnitude varying from 8.4 to 8.9. Also an evening object, it is stationary on the 7th.

(29) Amphitrite is in Pisces all month, its magnitude fading from 8.9 to 9.6. It will be just over 1° north of the mag 3.6 star eta Psc mid- month. It sets well after midnight all month.

(192) Nausikaa is in Perseus and rather low in NZ skies. It starts November at magnitude 9.4 a little over a degree from the magnitude 2.9 star zeta Per. During November Nausikaa brightens to magnitude 9.0 at opposition on the 17th. By the end of November it will have faded again to 9.3. The asteroid rises about 11 pm on the 1st and at sunset on the 30th.

-- Brian Loader

6. Variable Stars South 4th Symposium - March 24

The National Australian Convention of Amateur Astronomers (NACAA) will hold its 27th meeting in Sydney over the 2016 Easter long weekend. NACAA will be hosted by the Sutherland Astronomical Society Inc, and will be held at the new Law Annexe at the University of NSW. Details of accommodation and the like will be posted to the NACAA website soon.

While details of the programme are still being finalised, it is intended that Variable Stars South (VSS) will hold its 4th Symposium on the Friday (March 25 - Good Friday).

Members of the VSS community are invited to submit papers and posters via the NACAA website (http://www.nacaa.org.au/2016/proposal) for either the Symposium (most likely focused on specific research reports and the like) or the main NACAA meeting (more general variable star observing subjects).

More details of the event can be found at the NACAA website, and if you register your interest you will receive alerts as they are posted.

-- David O´Driscoll, Programme Committee Chair, NACAA 2016 & VSS Webmaster

7. 2016 Beatrice Hill Tinsley Lecturer

The RASNZ Lecture Trust is pleased to announce that the 2016 Beatrice Hill Tinsley lecturer will be Dr Michael Person. Dr Person is a research scientist at the Massachusetts Institute of Technology Planetary Astronomy Laboratory. His interests include observational astronomy, focusing on the techniques needed to observe stellar occultations, eclipses, and transits; and identifying and characterizing the atmospheres, compositions, and figures of solar system bodies. Dr Person has a special interest in distant solar system bodies, specifically Triton, Pluto, and Kuiper Belt Objects and so the lectures will focus on Pluto and the recent New Horizons mission. The lecture tour will take place during July-August 2016. Expressions of interest are invited from Affiliated Societies to host one of the 2016 BHT lectures. Societies have until the end of October to contact the RASNZ Lecture Trust at This email address is being protected from spambots. You need JavaScript enabled to view it. to register their interest.

-- Gary Sparks, Secretary, RASNZ Lecture Trust.

8. Ceres Bright Spots Seen in More Detail

The brightest spots on the dwarf planet Ceres gleam with mystery in new views delivered by NASA's Dawn spacecraft. These closest-yet views of Occator crater, with a resolution of 140 meters per pixel, give scientists a deeper perspective on these very unusual features.

The individual animations are available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19890 http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19891

The new up-close view of Occator crater from Dawn's current vantage point reveals better-defined shapes of the brightest, central spot and features on the crater floor. Because these spots are so much brighter than the rest of Ceres' surface, the Dawn team combined two different images into a single composite view -- one properly exposed for the bright spots, and one for the surrounding surface.

Scientists also have produced animations that provide a virtual fly- around of the crater, including a colourful topographic map.

Dawn scientists note the rim of Occator crater is almost vertical in some places, where it rises steeply for nearly 2 km.

Views from Dawn's current orbit, taken at an altitude of 1,470 km, have about three times better resolution than the images the spacecraft delivered from its previous orbit in June, and nearly 10 times better than in the spacecraft's first orbit at Ceres in April and May.

-- From a NASA JPL press release forwarded by Karen Pollard.

9. Enceladus's Global Ocean

A global ocean lies beneath the icy crust of Saturn´s geologically active moon Enceladus, according to new research using data from NASA´s Cassini mission.

Researchers found the magnitude of the moon´s very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.

The finding implies the fine spray of water vapour, icy particles and simple organic molecules Cassini has observed coming from fractures near the moon´s south pole is being fed by this vast liquid water reservoir. The research has been presented in a paper published online in the journal Icarus.

Previous analysis of Cassini data suggested the presence of a lens- shaped body of water, or sea, underlying the moon´s south polar region. However, gravity data collected during the spacecraft´s several close passes over the south polar region lent support to the possibility the sea might be global. The new results -- derived using an independent line of evidence based on Cassini´s images -- confirm this to be the case.

Cassini scientists analysed more than seven years´ worth of images of Enceladus taken by the spacecraft, which has been orbiting Saturn since mid-2004. They carefully mapped the positions of features on Enceladus -- mostly craters -- across hundreds of images, in order to measure changes in the moon´s rotation with extreme precision.

As a result, they found Enceladus has a tiny, but measurable wobble as it orbits Saturn. Because the icy moon is not perfectly spherical -- and because it goes slightly faster and slower during different portions of its orbit around Saturn -- the giant planet subtly rocks Enceladus back and forth as it rotates.

The team plugged their measurement of the wobble, called a libration, into different models for how Enceladus might be arranged on the inside, including ones in which the moon was frozen from surface to core.

If the surface and core are rigidly connected, then the core would provide so much dead weight the wobble would be far smaller than is observed. This proves that there must be a global layer of liquid separating the surface from the core.

The mechanisms that might have prevented Enceladus´ ocean from freezing remain a mystery. Among ideas for future study is the surprising possibility that tidal forces due to Saturn´s gravity could be generating much more heat within Enceladus than previously thought.

The unfolding story of Enceladus has been one of the great triumphs of Cassini´s long mission at Saturn. Scientists first detected signs of the moon´s icy plume in early 2005, and followed up with a series of discoveries about the material gushing from warm fractures near its south pole. They announced strong evidence for a regional sea in 2014, and more recently, in 2015, they shared results that suggest hydrothermal activity is taking place on the ocean floor.

Cassini is scheduled to make a close flyby of Enceladus on Oct. 28, in the mission´s deepest-ever dive through the moon´s active plume of icy material. The spacecraft will pass a mere 49 km above the moon´s surface.

For the original text & Images see: http://www.ciclops.org/view.php?id=8199 http://www.jpl.nasa.gov/news/news.php?release=2015-298

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

10. Perplexing Images of Pluto

The newest high-resolution images of Pluto from NASA´s New Horizons are both dazzling and mystifying, revealing a multitude of previously unseen topographic and compositional details.

One image, showing an area on Pluto´s best-mapped hemisphere near the line that separates day from night, captures a vast rippling landscape of strange, aligned linear ridges that has astonished New Horizons team members. It may have been made by some combination of internal tectonic forces and ice sublimation driven by Pluto´s faint sunlight.

The spacecraft also captured the highest-resolution colour view yet of Pluto -- along with detailed spectral maps and other high-resolution images. The new "extended colour" view of Pluto -- taken by New Horizons´ wide-angle Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14 and downlinked to Earth on Sept. 19 -- shows the extraordinarily rich colour palette of Pluto.

Additionally, a high-resolution swath across Pluto taken by New Horizons´ narrow-angle Long Range Reconnaissance Imager (LORRI) on July 14, and downlinked on Sept. 20, homes in on details of Pluto´s geology. These images, the highest-resolution yet available of Pluto, reveal features that resemble dunes, the older shoreline of a shrinking glacial ice lake, and fractured, angular, jammed-together water ice mountains with sheer cliffs.

This closer look at the smooth, bright surface of the informally named Sputnik Planum shows that it is actually pockmarked by dense patterns of pits, low ridges and scalloped terrain. Dunes of bright volatile ice particles are a possible explanation, mission scientists say, but the ices of Sputnik may be especially susceptible to sublimation and formation of such corrugated ground.

Beyond the new images, new compositional information comes from a just- obtained map of methane ice across part of Pluto´s surface that reveals striking contrasts: Sputnik Planum has abundant methane while the region informally named Cthulhu Regio shows none, apart from a few isolated ridges and crater rims. Mountains along the west flank of Sputnik lack methane as well.

The distribution of methane across the surface is anything but simple, with higher concentrations on bright plains and crater rims, but usually none in the centres of craters or darker regions. Outside of Sputnik Planum, methane ice appears to favour brighter areas, but scientists aren´t sure if that is because methane is more likely to condense there or that its condensation is what brightens those regions.

For the full text & Images see: http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150924

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

11. The Sculptor Dwarf Galaxy's Evolution

As part of its public image display the European Southern Observatory (ESO) has published an image of the Sculptor Dwarf Galaxy. The photo was obtained with the Wide Field Imager camera, installed on the 2.2- metre MPG/ESO telescope at ESO´s La Silla Observatory.

The Sculptor Dwarf Galaxy is a close neighbour of our galaxy, the Milky Way. Despite their close proximity, both galaxies have very distinct histories and characters. The Sculptor Dwarf Galaxy is much smaller and older than the Milky Way, making it a valuable subject for studying both star and galaxy formation in the early Universe. However, due to its faintness, studying this object is no easy task

The Sculptor Dwarf Galaxy - also known as the Sculptor Dwarf Elliptical or the Sculptor Dwarf Spheroidal - is a dwarf spheroidal galaxy, and is one of the fourteen known satellite galaxies orbiting the Milky Way. These galactic hitchhikers are located close by in the Milky Way´s extensive halo, a spherical region extending far beyond our galaxy´s spiral arms. As indicated by its name, this galaxy is located in the southern constellation of Sculptor and lies about 280 000 light-years away from Earth. Despite its proximity, the galaxy was only discovered in 1937, as its stars are faint and spread thinly across the sky. (This faint galaxy should not be confused with the much brighter Sculptor Galaxy, NGC 253, in the same constellation.)

Although difficult to pick out, the Sculptor Dwarf Galaxy was among the first faint dwarf galaxies found orbiting the Milky Way. The tiny galaxy´s shape intrigued astronomers at the time of its discovery, but nowadays dwarf spheroidal galaxies play a more important role in allowing astronomers to dig deeply into the Universe´s past.

The Milky Way, like all large galaxies, is thought to have formed from the build-up of smaller galaxies during the early days of the Universe. If some of these small galaxies still remain today, they should now contain many extremely old stars. The Sculptor Dwarf Galaxy fits the bill as a primordial galaxy, thanks to a large number of ancient stars, visible in this image.

Astronomers can determine the age of stars in the galaxy because their light carries the signatures of only a small quantity of heavy chemical elements. These heavy elements accumulate in galaxies with successive generations of stars. A low level of heavy elements thus indicates that the stars in the Sculptor Dwarf Galaxy are old.

This quantity of old stars makes the Sculptor Dwarf Galaxy a prime target for studying the earliest periods of star formation. In a recent study, astronomers combined all the data available for the galaxy to create the most accurate star formation history ever determined for a dwarf spheroidal galaxy. This analysis revealed two distinct groups of stars in the galaxy. The first, predominant group is the older population, which is lacking in heavier elements. The second, smaller population, in contrast, is rich with heavy elements. The youthful stellar population is concentrated toward the galaxy´s core.

The stars within dwarf galaxies like the Sculptor Dwarf Galaxy can exhibit complex star formation histories. But as most of these dwarf galaxies´ stars have been isolated from each other and have not interacted for billions of years, each collection of stars has charted its own evolutionary course. Studying the similarities in dwarf galaxies´ histories, and explaining the occasional outliers, will help to explain the development of all galaxies, from the most unassuming dwarf to the grandest spirals. There is indeed much for astronomers to learn from the Milky Way´s shy neighbours.

To see the Sculptor Dwarf Galaxy image go to http://www.eso.org/public/images/archive/search/?adv=&facility=15 and enter'eso1536' into the search window.

-- From an ESO press release forwarded by Karen Pollard.

12. Galaxy Cluster with Star-Burst Core

An international team of astronomers has discovered a gargantuan galaxy cluster with a core bursting with new stars - an incredibly rare find. The discovery, made with the help of the NASA/ESA Hubble Space Telescope, is the first to show that gigantic galaxies at the centres of massive clusters can grow significantly by feeding off gas stolen from other galaxies.

Galaxy clusters are vast families of galaxies bound together by gravity. Our own galaxy, the Milky Way resides within a small galaxy group known as the Local Group, which itself is a member of the massive Laniakea supercluster.

Galaxies at the centres of clusters are usually made of stellar fossils - old, red or dead stars. However, astronomers have now discovered a giant galaxy at the heart of a cluster named SpARCS1049+56 that seems to be bucking the trend, instead forming new stars at an incredible rate. It appears that the giant galaxy has recently collided with, and merged with, a smaller galaxy rich in gas. The gas is now forming into stars at the rate of 800 new stars per year. The Milky Way forms two stars per year at most!

The galaxy was initially discovered using NASA´s Spitzer Space Telescope and the Canada-France-Hawaii Telescope, located on Mauna Kea in Hawai`i and confirmed using the W.M. Keck Observatory, also on Mauna Kea. Follow-up observations using the NASA/ESA Hubble Space Telescope allowed the astronomers to explore the galaxy´s activity.

The Spitzer data showed us a truly enormous amount of star formation in the heart of this cluster, something that has rarely been seen before, and certainly not in a cluster this distant.

The SpARCS1049+56 cluster is so far away that its light took 9.8 billion years to reach us. It houses at least 27 galaxies and has a combined mass equal to 400 trillion Suns. It is a truly unique cluster in one aspect - its vibrant heart of new stars.

Spitzer picks up infrared light, so it can detect the warm glow of hidden, dusty regions of star-birth. Follow-up studies with Hubble in visible light helped to pinpoint what was fuelling the new star formation.

Building on their other observations the team used Hubble to explore the galaxy in depth. What they found was a "train wreck" of a merger at the centre of this cluster. The images showed features that looked like beads on a string."

Beads on a string are a tell-tale signs of something known as a "wet merger". Wet mergers occur when gas-rich galaxies collide. The gas is then converted quickly into new stars. "Dry mergers" involve the coming together of two galaxies lacking in gas. The two just mix their existing stars, rather than causing the birth of any new ones.

The new discovery is one of the first known cases of a wet merger at the core of a galaxy cluster. Hubble had previously discovered another closer galaxy cluster containing a wet merger, but it was not forming stars as vigorously. Other galaxy clusters grow in mass through dry mergers or by siphoning gas towards their centres. For example, the mega galaxy cluster known as the Phoenix Cluster grows in size by sipping off gas that flows into its centre.

The astronomers now aim to explore how common this type of growth mechanism is in galaxy clusters. Are there other "messy eaters" out there similar to SpARCS1049+56, which also munch on gas-rich galaxies? SpARCS1049+56 may be an outlier - or it may represent an early time in our Universe when messy eating was the norm.

These new results are presented in a paper entitled "An Extreme Starburst In The Core Of a Rich Galaxy Cluster At z = 1.7", published in The Astrophysical Journal on 21 August 2015.

For more see: https://www.spacetelescope.org/videos/heic1414a/http://www.spacetelescope.org/static/archives/releases/science_papers/h eic1519a.pdf

-- From a press release forwarded by Karen Pollard.

13. Massey University Introductory Astronomy Course

In the second semester of 2015 (13 July 2015 - 11 November 2015) Massey University´s Manawatu campus has been running an introductory astronomy paper at first year level. The paper is being run in conjunction with an existing paper at Massey´s Albany campus, and is taught by Jeremy Moss (who is also the President of the Palmerston North Astronomical Society) and Stephen Chadwick (also President of the Horowhenua Astronomical Society). The paper includes a practical observing component as part of the assessment, and it covers the following topics: the Solar System and astronomical history; the Sun and stars; galaxies and cosmology.

The paper is designed to cover the basics of astronomy for non-science students, but it also links in with Massey´s second year paper in Special Relativity and Cosmology.

It will also be run in the second semester of 2016, and there are plans For extending it to an extramural option in the future. For more details, please contact Jeremy Moss at This email address is being protected from spambots. You need JavaScript enabled to view it.

14. How to Join the RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/rasnz/membership-benefits A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/rasnz/membership-application Basic membership for the 2015 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

15. 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. Applications are now invited for grants from the Kingdon-Tomlinson Fund. The application should reach the Secretary by 1 November 2015. 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.

16. Quote

"In 'Birth of a Rocket' [Scientific American, June 2015, p.44], David H. Freedman reports that 'the real justification for human spaceflight is to take steps toward expanding the human race's stomping grounds.' Does he mean for a few elite astronauts or humanity generally? The former may be achievable - but why bother? The latter seems just shy of delusional. Either way, wouldn't it be more sensible to take the up to $1 trillion that a trip to Mars might cost and use it to prevent the collapse of liveable conditions on Earth?" -- Evan Fales.

Newsletter editor:

Alan GilmorePhone: 03 680 6817
P.O. Box 57Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand