MEETINGS

OCTOBER  MEETING

        The October meeting was opened by John Vale-Taylor who reminded members that Winchester had invited Society members to an Astronomy Day on Sunday 5 December as mentioned in the September Newsletter.  Those interested in going and taking advantage of the ticket reduction for members to £12 should let Phil Berry know and he will forward all full names so that they can be collected on entry to the event on the day.  There is more about this invitation later in the Newsletter.

        Then John introduced Ian King who had changed the subject of his talk.

Astro-photography    Ian  King

        In preparing his original talk, Ian told the meeting that his illustrations had ‘disappeared’, but instead we were rewarded by an brilliant talk on Astro-photography instead, which he had recently given to Ashford Astronomical Society.

        First Ian compared the advantages and disadvantages of film in opposition to digital photography.  Film, he said was cheap, simple, capable of wide-field imaging and also film cameras were relatively cheap these days.  Disadvantages included problems caused by light pollution and reciprocity failure where, at low light levels, increasing the exposure time fails to increase the exposure in the emulsion.

        Advantages of digital photography techniques include much greater sensitivity, a wider dynamic range, much wider response, linear response and no halation which can result in a certain amount of halo occurring round small specula in film. Disadvantages include more expensive equipment and greater complexity.

        To begin with, we looked at film cameras using a static tripod to produce images of the moon, star trails and twilight silhouettes of the night sky.

        Digital Single Lens Reflex cameras such as Canon and Nikon can be especially suitable for Astro-photography.  The “B” (bulb) setting allows the shutter to remain open for long exposures and remote control operation prevents camera shake from spoiling an exposure.  Ian showed the effect on film of light pollution and the use of light-pollution filters to greatly improve results, but then we were shown results using digital cameras with astounding results.  One image he showed was taken from the Canary Islands revealing the Zodiacal light.  Another one was of the moon during a lunar eclipse showing the advantages of being able to use a longer focal length.

        Long wide-field images of the stars revealed not only the movement of the stars but clearly showed their colours.

        When using a DSLR camera for long exposures of the night sky, Ian showed a “barn-door” method of tracking by using two boards, hinged at the left hand side like a book, with the hinge in line with the polar axis and the camera mounted on the “open-page”.  The open side of this board has a bolt through it so that as the sky appears to turn, a bolt is screwed in every minute at the correct rate, tracking the camera in sync with the sky.

        Then we saw the result from a DSLR camera mounted on an easily transported Astrotrack mount which incorporates a pole finder and which tracks the camera.  A 15 minute exposure image of Sagittarius compared with film showed no halation and the results shown a great improvement in the resolution of individual stars.

        With the camera placed at the prime focus of a telescope it enabled much higher magnification although things are much more critical and autofocus and auto guiding are now more desirable on long exposures although with a digital camera it is possible to take lots of exposures, using software to combine them to create one long exposure.

        Ian stressed the importance of a good solid mount as images from deeper space are made, with the use of polar axis alignment.  But as he says, transport becomes a lot more difficult.  On a recent trip to Tenerife the cost of air transport was prohibitive so he sent the mount by boat, but it actually took 8 weeks to get there, although he used good forward planning.

        In this country it is important to have an observatory so that everything can be set up ready for when the skies clear and Ian showed a picture of his own dome at home stuffed full of very interesting equipment.

        We looked at the use of narrow band filters to reduce the effects of light pollution and for more dramatic results, particularly by the use of hydrogen-alpha and Oxygen 3 filters. One remarkable image Ian showed was of the twisting turbulence at the middle of the Heart Nebula, IC 1805, using a Hydrogen-alpha and Sulphur 2 filter to reduce the effects of light pollution and improve the contrast and definition, to reveal an intricate web of fine detail.

        An image of the Crab Nebula, M1 revealed the extraordinary expansion of the gases.

        The detail in an image of the Horse Head Nebula clearly showed how the gases twist to form the familiar shape we see from Earth.

 

The Horse Head Nebula – Image by Ian King

        A beautiful image Ian had taken of the Pleiades clearly showed how the gases diffuse light from the main stars.

        Finally we were shown an image of the Cat’s Paw Nebula in the southern hemisphere taken through a Hydrogen-alpha filter, and Ian mentioned how image processing can aid in improving contrast.

NOVEMBER  MEETING

        Wednesday 17th November 2010 – Society member Trevor Grey gives an illustrated talk with the intriguing title; “It Is Rocket Science”.

        Meetings begin at 1930 although members are invited to arrive anytime after 1900 as this is a good time to exchange ideas and discuss problems and relax before the meeting.

        The venue as always is held in the Upper Room of the Methodist Church at the east end of Wadhurst Lower High Street, opposite the entrance to Uplands College.  (For those with SatNav – the post code is TN5  6AT)

FUTURE  MEETINGS

        Wednesday 15th December 2010 – Brian Mills gives a very appropriate talk about “The Star of Bethlehem”.  This will be followed by hot drinks and mince pies!

OTHER NOTES AND INFORMATION

WINCHESTER PLANETARIUM

        In the September issue of the Newsletter there was an invitation to an Astronomy Event at Winchester Planetarium on Sunday the 5th of December 1020 from 1030 to 1630, although Astronomy Societies get early entrance from 0930.  Members will need to arrange their own transport.

        The programme includes various talks, planetarium shows, workshops on Astro-photography and on the use of Equatorial mounts.  There will also be static displays.

        More information is available on the INTECH Science & Planetarium website at:  http://www.intech-uk.com

        Phil Berry has suggested that any member interested in going should contact him and let him have all full names then he will contact the centre on their behalf to arrange tickets to be ready on the door at the reduced price of £12 when we arrive there on the day.  He will need to have names by or at the next meeting which is on Wednesday 17 November.

MEMORIAL TALK BY DR ALLAN CHAPMAN

The following message has been received by the Society:

To SAGAS members

Andy Lawes

Treasurer & Founder member of East Sussex AS has asked for the following to be circulated:-

WE are holding a memorial talk for Peter Ellis who worked for many years at Herstmonceux Observatory and as you can see we have an eminent speaker giving the Memorial talk on Thursday evening November 4th starting at 8pm.

Peter’s wife and son will also be attending and we will be raising money during the break for St Michaels Hospice

I’ve said good bye to a lot of members in the twelve years since I started East Sussex Astronomical Society and we thought it fitting to focus on the members we have lost. We have many that are suffering with cancer so we thought that we would use this opportunity to raise some funds.

The memorial talk will be held at St Mary’s School, Wrestwood Road , Bexhill on Thursday 4th November starting at 8pm £2 on the door for non members all are welcome tea/coffee and biscuits included.

Telephone 01424 819450 or email for further details

Kind regards

Andy Lawes  Founder of ESAS

Dr Allan Chapman Presents ‘The Herschels’ Special Memorial Talk dedicated to Peter Ellis who sadly died after his fight against cancer.  Peter joined ESAS in 2002 and has helped our society with various projects over the years.

Dr Allan Chapman who will be giving this memorial talk is a Historian, Lecturer and TV presenter and an excellent charismatic speaker, who will enthral you even if your knowledge on Astronomy is limited.

I do hope you will be able to attend this talk as we have many members who are fighting this illness.  A collection for St Michael’s hospice will be held during the break.

RECENT VISIT TO THE RUTHERFORD APPLETON LABORATORIES, HARWELL

        At a recently meeting Phil Berry announced that there were tickets available for a visit to the Rutherford Appleton Laboratory at Harwell, just south of Oxford on Saturday the 2nd of September, organised by the Society for Popular Astronomy to which a number of members went.

Rutherford Appleton Laboratories - Harwell

        The Rutherford Appleton Laboratory (RAL) site is adjacent to what used to be the Harwell Atomic Energy Research Establishment from the 1940s to the 1990s.

        RAL houses the huge Diamond Light Source synchrotron used for research from particle physics to industrial x-rays as used to monitor the quality of metals used in modern jet engines.

        The day started at 10.00 and consisted of five talks but also included a guided tour of the satellite assembly and testing facility.

        The talks were given in the Rutherford Appleton Lecture Theatre and given by RAL scientists and researchers in some of the latest fields connected with space.

        The first talk described how the solar wind is created and showed the latest methods of gathering data and information from satellites and the prediction of solar winds in the direction of the Earth.  This is becoming important as we rely more and more on computer technology for communications and digital control systems.  The danger is the arrival of a sufficiently large cloud could cause a magnetic pulse that might destroy or interfere with many micro-electronic systems both in space and on the ground.

        The second presentation was an update on the Rosetta mission launched in March 2004.  The mission is to investigate the composition of a short period comet and also in passing, to investigate asteroid Lutetia which it did in July this year.

        The Rosetta satellite is just about to go into hibernation for its intended rendezvous with comet Churyumov-Gerasimenko in May 2014, a distance of more than five times the distance of the Earth to the Sun.  It will then send a probe to land on the surface of the comet to collect data, and then continue in orbit around the comet for the next two years before heading for the Sun.

        After lunch in the laboratory’s restaurant, we attended the third talk which was about the hazard posed by near Earth objects and given by one of the professors at RAL.  The question seems to be alarmingly not “if” but “when” there is an encounter and what we can do about it.  The talk included many visible examples of where the Earth has already been hit by objects in the past, such as the Gulf of Mexico some 65 millions years ago and more recently the Barringer Crater in Arizona, 50,000 years ago and Tunguska in Siberia in 1908.

        One method of dealing with an object being considered might be to use something called a Gravity Tractor that would drag an object sufficiently off course by the use of a gravity source to at least bounce off the Earth’s atmosphere.

        The fourth talk was an update on the exploration of Mars, but we had to miss this to join a tour round the Space Probe Assembly and Testing Facility where we were first visited the satellite control room.  One of the bays had been used by NASA during the Apollo 16 mission and still had some of the original Apollo 16 labels.  This system consisted of three large bays but had now been replaced by one single bay that only had a third of its capacity filled.  The bay was used to download and control orbiting satellites as they pass overhead.

        Another bay was used to control the site’s own satellite dish.  At present this is being used to download data from the ACE (Advanced Composition Explorer) satellite positioned at libration point L1 and amongst other things, monitors particle emitted by the Sun and this would be one of the early warning methods of Solar Wind advancing towards the Earth.

        We visited the assembly area where 45 ultra low temperature cooling systems are being built for use not in space but on the Atacama Large Millimetre Array in Chile.  ALMA will consist of a number of radio receiving dishes in a huge array and will study the night sky in detail at sub-millimetre wavelengths, observing the birth of stars and detecting the earliest galaxies created at the Big Bang.  These cooling devices will take the temperature of the receivers down to -277o C (4o Kelvin).

        We were able to look through a window at one of the clean rooms where a very high definition imaging satellite was ready to be transported to the European Space Agency for launch.

        The final part of the facility we visited was a huge 8-foot diameter; 20 foot long chamber into which probes to be used on satellite missions are place for testing.  The chamber is then evacuated and the temperature lowered to -170o C, where probes are tested for several months at a time.  We were told that vibration tests are carried out elsewhere and involve forces as high as 100 G.

        The last talk of the day was about the search for life beyond the Earth by professor M orison from Jodrell Bank in Cheshire.  He had been heavily `involved with SETI programme, the “Search for Extra-Terrestrial Intelligence” and as he explained we are probably not alone, but the chance of communicating with anything was exceedingly remote.

SKY NOTES FOR NOVEMBER

Planets

Mercury is not observable this month having suffered a superior conjunction last month.

Venus suffered an inferior conjunction last month but is now re-appearing as the “Morning Star” in the east before dawn. It currently lies in the constellation of Virgo at magnitude -4.5 and by mid month rises two hours before the Sun.

Mars is not suitably placed for observation this month.

Jupiter is still the planetary jewel in the evening sky shining at magnitude -2.6 in the constellation of Aquarius a little way below the Square of Pegasus. It continues to travel retrograde (east to west) until the 19th when it reaches its second stationary point, after which it resumes its direct motion (west to east).

Saturn is also in the constellation of Virgo, at magnitude +0.9 rising at 03.00 by the middle of the month with its rings now gradually opening as viewed from Earth.

Uranus at magnitude +5.7 is still close to Jupiter as the diagram illustrates.

Lunar Occultations

        In the table below I’ve only listed events for stars down to magnitude 7.0 that occur before midnight although there are others that are either of fainter stars or occur in the early hours.

DD = disappearance at the dark limb whilst RD = reappearance at the dark limb. Times are in GMT. I’ve included diagrams of the two brightest events to aid recognition, particularly in the case of the event on the 25th so that you know exactly where to look to see the star reappear. This star is actually a double made up of components with magnitudes of 4.9 and 5.8.

Nov

Time

Star

Mag.

Ph

PA °

11th

17.28

SAO 163107

6.9

DD

25

12th

17.33

SAO 163848

7.0

DD

95

15th

16.21

SAO 146412

6.2

DD

127

16th

19.47

SAO 128374

4.9

DD

59

17th

16.23

SAO 109195

6.8

DD

19

18th

16.40

SAO 92310

6.9

DD

28

19th

21.40

SAO 92810

6.4

DD

51

25th

20.55

SAO 97221

4.9

RD

264

Phases of the Moon for November

New

First ¼

Full

Last ¼

6th

13th

21st

28th

ISS

        Below are details of passes of the ISS as seen from Wadhurst that are brighter than mag. -3. The details of all passes including those visible from other areas can be found at:

www.heavens-above.com

        Please remember that the times shown below are for when the ISS is at it’s maximum elevation, so you should be able to see it for a few minutes before and after these times.  Times are in GMT.

Nov

Mag

Time

Alt°

Az.

2nd

-3.4

17.42

61

SSE

3rd

-3.7

18.08

86

N

4th

-3.4

16.59

65

SSE

4th

-3.1

18.33

58

WNW

5th

-3.6

17.25

84

NNW

6th

-3.7

17.50

77

N

7th

-3.6

16.41

82

N

7th

-3.7

18.16

85

SSW

8th

-3.6

17.07

77

N

9th

-3.6

17.33

82

SSW

11th

-3.5

16.49

79

SSW

Iridium Flares

        The flares that I’ve listed are magnitude -3 or brighter although there are a lot more that are fainter or occur after midnight.  If you wish to see a complete list, or obtain timings for somewhere other than Wadhurst, go to:

www.heavens-above.com

        Remember that when one of these events is due it is often possible to see the satellite in advance of the “flare”, although of course it will be much fainter at that time.  Times are in GMT.

Nov

Time

Mag

Alt°

Az.

2nd

18.48

-5

42

SE

7th

18.27

-8

42

SSE

12th

18.06

-3

40

SSE

17th

17.45

-5

37

S

21st

17.30

-7

35

S

25th

17.15

-7

31

S

29th

18.26

-3

34

SSE

Meteors

The Leonids are active from November 15th to the 20th with maximum occurring on the night of the 17th/18th when a zenithal hourly rate (ZHR) of around 20 is expected. The Moon interferes to a degree this year rising at 14.00 and setting at 03.00 on the night of maximum. This shower is always more of an “early hours” event as the radiant doesn’t rise until 23.00. The diagram shows you how to find Leo by using the Plough and the position of the radiant within the “Sickle” of Leo is shown by the ® symbol.

The Taurids reach their peak with a ZHR of 10 on November 5th but go on until around the 30th. The radiant has risen by 18.00 so it will have reached a reasonable altitude above the south eastern horizon well before midnight. The position of the radiant is again indicated by the ® symbol.

Comet

        As is common with comets, 103P/Hartley doesn’t seem to have lived up to expectations possibly because it was more diffuse than originally thought and is reportedly two to three magnitudes fainter than expected.

The Night Sky in November

        Looking east at 22.00 around the middle of the month, the winter constellations of Orion, Gemini and Canis Minor are rising. Above them Taurus (with its open cluster the Pleiades) and Auriga are high in the sky.

        Turning to the south Pegasus and Andromeda have just passed the meridian so this is an ideal time to see M31, the Great Andromeda Spiral visible to the naked eye as a misty patch but seen better in binoculars or a small telescope. Jupiter is still a brilliant object a little west of south. If you have binoculars have a look and see how many of its Galilean moons you can see. If you can, mount your optical aid on a tripod or if not brace yourself against a wall or fence because you will see far more if you can keep the image steady.

        In the west the Summer Triangle is dipping towards the horizon with Altair being the first of the three to disappear from sight.

        Looking north at the circumpolar constellations, Ursa Major is beginning to climb again whilst Cassiopeia is almost overhead. Ursa Minor is pointing down towards the horizon and towards the tail of its larger relation whilst Draco is entwined between the two bears.

Brian Mills

DEFINITIONS OF TERMS USED IN ASTRONOMY

Circumpolar

        Stars and constellations that are referred to as circumpolar are ones that will never set below the observer’s horizon. This is simply due to their proximity to the celestial pole.

        As we know the Earth rotates on its axis from west to east causing everything in the sky to appear to move from east to west. The points around which this rotation of the heavens appears to take place are called the celestial poles. The north celestial pole is marked almost exactly by the star Polaris in the constellation of Ursa Minor and as we travel further south so Polaris gets lower and lower in the sky. It therefore follows that what we know as circumpolar objects from say the south of England are not all going to be circumpolar from for example the south of France. If we were to travel to the equator where theoretically the north and south poles would lie on opposite horizons then there would be no such thing as a circumpolar object. Likewise if we were standing at the north pole, the north celestial pole would be directly above us and all celestial objects would of course appear to rotate around it. Again in this instance there are no circumpolar objects because in this case nothing would set below the horizon.

Earthshine

        When the Moon is at a crescent phase (during both waxing and waning) it is often possible to see the dark portion faintly illuminated. This is known as Earthshine (or the old Moon in the new Moon’s arms) and is caused by sunlight being reflected off the Earth and onto the Moon. As you can see from the diagram at “new” the Moon it is invisible to us but as it moves towards 1st quarter we see an increasing crescent appearing. At this time a large part of the sunlit Earth is turned towards the Moon providing a large reflective area to illuminate the otherwise dark and invisible part.

        As long ago as the fifteen hundreds Leonardo da Vinci realised that the Moon only shines due to sunlight being reflected and not because it has any light of its own.

Brian Mills

NASA’S SPACE PLACE

Close Encounters with Jupiter

by Dr. Tony Phillips

        Jupiter and Earth just had a close encounter—and it was a good one. In late September 2010, the two worlds were 31 million km (about 19 million miles) closer than at any time in the past 11 years. Soaring high in the midnight sky, Jupiter shone six times brighter than Sirius and looked absolutely dynamite through a backyard telescope.

        Planetary scientist Scott Bolton of the Southwest Research Institute isn’t satisfied. “I’d like to get even closer,” he says.

Bolton will get his wish in July 2016. That’s when a NASA spacecraft named “Juno” arrives at Jupiter for a truly close-up look at the giant planet. Swooping as low as 5,000 km (about 3,000 miles) above the cloud tops, Juno will spend a full year orbiting nearer to Jupiter than any previous spacecraft.

        The goal of the mission is to learn what lies inside the planet.

Astronomers have been studying Jupiter since the invention of the telescope 400 years ago, but in all that time the planet’s vast interior has remained hidden from view. Even the Galileo probe, which dived into the clouds in 1995, penetrated no more than about 0.1% of Jupiter’s radius.

        “Our knowledge of Jupiter is truly skin deep,” says Bolton, Juno’s principal investigator. “There are many basic things we just don’t know—like how far down does the Great Red Spot go? And does Jupiter have a heavy core?”

        Juno will improve the situation without actually diving into the clouds. Bolton explains how. “Juno will spend a full year in close polar orbit around Jupiter, flying over all latitudes and longitudes. We will thus be able to fully map Jupiter’s gravitational field and figure out how the interior is structured.”

        But that’s not all. Researchers have good reason to believe that much of Jupiter’s interior is filled with liquid metallic hydrogen, an exotic metal that could form only in the high-pressure, hydrogen-rich core of a giant planet. Jupiter’s powerful magnetic field almost certainly springs from dynamo action inside this vast realm of electrically conducting metal.

        “Juno’s magnetometers will precisely map Jupiter’s magnetic field,” says Bolton. “This map will tell us a great deal about planet’s inner magnetic dynamo—what it’s made of and how it works.”

        Finally, Juno will probe Jupiter’s atmosphere using a set of microwave radiometers. “Our sensors can measure the temperature 50 times deeper than ever before,” says Bolton. Researchers will use that information to figure out how much water is underneath Jupiter’s clouds. “Microwave measurements of Jupiter’s water content are particularly exciting because they will help discriminate among competing theories of the planet’s origin.”

        Now that’s a close encounter. Stay tuned for Juno.

        Find out more about the Juno mission at:

http://www.nasa.gov/mission_pages/juno

        Play the new Solar System Explorer super game, which includes the Juno Recall mini-game at:

http://spaceplace.nasa.gov/en/kids/solar-system

        It’s not just for kids!

This article was provided courtesy of the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Caption:

The Juno mission, arriving at Jupiter in July 2016, will help to solve the mystery of what’s inside the giant planet’s core.

CONTACTS

Chairman     John Vale-Taylor

                                                      pjvalet1@btinternet.com

Secretary & Events                 Phil Berry             01892 783544

                                                      phil.berry@tiscali.co.uk

Treasurer            Mike Wyles                          01892 542863

                                                      mike31@madasafish.com

Editor            Geoff Rathbone                         01959 524727

                                                      geoff@rathbone007.fsnet.co.uk

Director of Observations       Brian Mills    01732 832691

                                                      Brian@wkrcc.co.uk

Wadhurst Astronomical Society website:

                                                      www.wadhurst.info/was/

SAGAS web-site                        www.sagasonline.org.uk

Any material for inclusion in the December 2010 Newsletter should be with the Editor by November 28th 2010