WADHURST ASTRONOMICAL SOCIETY

APRIL NEWSLETTER 2009

INDEX: MEETINGS, OTHER NEWS, CONTACTS

MEETINGS

  COMMITTEE MEETING

        Members of the Committee are respectfully reminded that there is a meeting of the Committee on Tuesday the 7th of April starting at 1930.  Phil Berry has kindly suggested that the meeting takes place at his house again.
        Phil has also extended the welcome to any member of the Society interested in coming along.  Details can be obtained from Phil Berry.

INTERNATIONAL YEAR OF ASTRONOMY 2009
THE SPRING MOON- WATCH

        The International Year of Astronomy 2009 (IYA) is an exciting global celebration of astronomy and its contributions to society and culture.  Coinciding with the 400th anniversary of Englishman, Thomas Harriet’s and the more famous Galileo’s first glimpse through a telescope and the birth of modern astronomy, it gives people all over the world the chance to get involved in this fascinating science and experience the wonders of the night time sky.
        To mark the occasion, members of the Wadhurst Astronomical Society will be holding a Spring Moon watch for the members of the Society and the Sparrow Green Residents Association on the evening of Friday 3rd of April 2009 from 1930 until 2130.  Details from Phil Berry.
        As with any event in the UK there is no guarantee of a clear sky, however if the sky is not clear on the Friday evening the event will instead be held the following evening on Saturday 4th April 2009.  Failing this, another event will be arranged later in the year.
        Various telescopes and binoculars will be available and set up for visitors to use.  There will also be a live projection of the Moon fed from Phil’s observatory.  Members of the Society would be pleased to help those of you who have not looked through an astronomical telescope before and it is hoped that a view of Saturn will also be available as well as some deep sky objects.
        If you are interested please do pop along on the evening if the sky is clear.       Phil Berry

MARCH MEETING

        The meeting was introduced by our Chairman, John Vale-Taylor who has now fully recovered from the accident to his finger which prevented him Chairing our February meeting.
        Phil Berry gave details about the Society’s involvement in the International Year of Astronomy 2009 as mentioned above.
        Then our speaker for this month was introduced.  Rob Cray is very important to the Society because it was Rob who held a course in Astronomy at Uplands College just over ten years ago when, at the end of the course, the students suggested forming an Astronomical Society, and so he helped form the Wadhurst Astronomical Society.

THE MARCH MEETING’S TALK

The Apollo missions 1 to 12

        Rob began his talk by showing a video of President J F Kennedy’s speech in which he stated the USA’s intention to send a man to the moon and bring him safely back to the Earth before the decade was out.  That statement was made in 1961.
        In the very early days, during the Mercury tests, NASA even had to borrow a truck to transport the Mercury rocket.  The heat shield was found to be unsuitable and eventually it was formed out of equipment from a hardware shop.
        Many aspects of a mission to the moon had to be tried and tested such as proving that docking was possible and that Extra Vehicle Activities could be performed safely.  It was also going to be necessary to provide a simulator for training the astronauts.
        In February 1966 the Saturn 1B was ready for tests and by July of that year were proving successful.
        Another important consideration was providing means of a launch escape.
        In 1967 the first full test of Apollo 1 ended in disaster when the selected crew were performing training exercises in the command module when an electrical fault caused a fire which spread vary quickly in the atmosphere of pure oxygen.  Grissom, White and Chaffee were all killed in less than 17 seconds before the hatch could be opened.
        During the following investigation, 1,400 wiring faults were discovered; for future missions the atmosphere was changed and the hatch was modified to be opened in less than 10 seconds.
        Rob continued by telling us that after this set back Apollo 4 was launched in 1967 and the first real test of the Saturn V rocket engine was performed.  Success lead to Apollo 5, then to Apollo 6, the last of the unmanned flights.
        Apollo 7 was the first manned test flight in Earth orbit and took place in 1968.  Then later that year, Apollo 8 took Borman, Lovell and Anders out of Earth orbit and eventually into orbit around the moon before returning them to Earth.  We were shown the now famous first photograph of the Earth rising above the Moon’s horizon and Rob played a sound recording of the astronauts reading ten verses from the book of Genesis from the Old Testament of the Bible over Christmas.
        McDivitt, Schweikart and Scott flew in Apollo 9 and for the first time tested the Lunar Module, its engine, life support systems, navigation and docking manoeuvres whilst in orbit around the moon.
        It was Apollo 10, manned by Young, Stafford and Cernan that completed the tests, taking the Lunar Module down to as low as 50,000 feet above the Moon’s surface and back up again to dock with the Command module.  During the assent, temporary oscillation was caused by an incorrect switch setting on the gimbal lock.  Once Stafford and Cernan had transferred safely back into the Command Module the Lunar Module was jettisoned back towards the surface of the Moon.
        At the same time, the surface of the moon was being surveyed in preparation for the first Lunar landing with Apollo 11 in 1969 under the command of Neil Armstrong, accompanied by Buz Aldrin and Command Module pilot Mike Collins.
        We were shown a video of the landing and Rob told us that during the final landing procedure there was a pause in dialogue from the Lunar Module.  At this moment the computer showed programme alarm 1202.  This was immediately recognised by Jack Garman, a 21 year old “On Board” computer specialist at Mission Control as an old alarm used during simulation tests to indicate that the computer was being called upon to process too much data at one time.  Within seconds this was relayed to Neil Armstrong and the mission was able to continue safely.  Garman received a NASA award for his quick response.
        The landing itself had to be very cautious because they almost settled on the edge of a crater which might have made take-off precarious, but finally a safe landing was achieved.
        The crew elected to walk on the surface of the moon before the rest period built into the original procedure.
        After a successful surface operation when many photographs were taken, scientific instruments set up and samples of lunar soil and rocks collected, the crew prepared to leave the surface after 20 hours.
        The launch was uneventful and the Lunar Module successfully docked with the Command Module ready for the pull out of Lunar orbit to begin the return journey back to Earth.
        Apollo 12 saw Conrad, Gordon and Bean on a further mission to the surface of the Moon, but the take off from Cape Kennedy took place in poor weather and it is thought that the rocket was struck by lightening, which caused all the buses to trip out.  These were all re-set and it was decided that the mission should continue.
        The landing site on the Moon was chosen to be on an area known as the Ocean of Storms which had already been visited by an un-manned mission earlier in the programme.
        Conrad and Bean removed part of the Surveyor after it had been located and also took its camera for tests back on Earth.  Many more rock samples were collected and more instruments set-up such as seismic detectors and devices to record solar wind.
        After this successful mission, Apollo 13 was launched in April 1970, but a short time into its flight the crew reported a loud bang and instruments showed an under-volt fault.
        Rob said he would continue with Apollo 13 when he returned in September.  Members said how vivid the story had been and looked forward very much to welcoming Rob back later in the year.

APRIL MEETING

        Wednesday 15th April 2009 “The Sun Kings”, a talk to be given by Stuart Clark.  Stuart is one of the UK’s foremost astronomy journalists; in fact he is a former editor of Astronomy Now.  His talk takes us through the tragic life of Richard Carrington and tells how modern astronomy began.
        The meeting begins at 1930 although members are invited to arrive anytime after 1900 as this is a good time to exchange ideas and discuss problems.
        The venue as always is in the Upper Room of the Methodist Church at the east end of Wadhurst Lower High Street, and opposite the entrance to Uplands College.  (For those with SatNav – the post code is TN5  6AT)

        The meeting continued with coffee and biscuits and then concluded with a short talk on “Binoculars for Astronomy” followed by another short talk, this time on “Terminology used in Astronomy” which is reported in the Sky Notes later in the Newsletter.

FUTURE MEETINGS

        Wednesday 20th May 2009  - “Sputnik in Context” a talk by John Axtell who is a member of Guildford Astronomical Society, but is better known to members of WAS as the Secretary of the Southern Area Group of Astronomical Societies – SAGAS.

        Wednesday 17th June 2009  - Telescope Evening.  An open evening where members are encouraged to bring telescopes, attachments or other aids to astronomy they think other members would be interested in.  There will also be short demonstrations of an astronomical nature.

        Wednesday 15th July 2009 “Astro-archaeology in the British Isles”; A talk by Bob Seaney, a well known member of the Society who has given a number of talks in the past.  Bob has been doing his own research for some time and reveals what he has learnt.

        In August  We hope to have another Astro-Barbecue towards the end of August.  This has been a very pleasant evening for a number of years, when we have the opportunity to socialise and do a little observing at the same time if the weather is kind enough.

        Wednesday 16th September 2009 – “The Apollo Programme – Missions 13 to 17”  This is a continuation of the talk given by Rob Cray in March when he told us about the beginnings of the US Lunar exploration programme.

OTHER NEWS AND INFORMATION

SOCIETY VISIT TO SEE THE GREENWICH CLOCKS

        On Saturday the 21st of March, several Society members visited the Old Greenwich Observatory to join a guided tour lead by Jonathan Betts who had already taken us on a guided visit to see the largest private collection of clocks in the United Kingdom at Belmont House near Faversham two years ago.
        Jonathan is the Senior Specialist in Horology at Royal Greenwich Observatory and he continued his fascinating story of clocks.
        We began out on the terrace overlooking Greenwich Park and the National Maritime Museum at the bottom of the hill, and Jonathan gave a brief introduction to the Observatory, including its history; the purpose of the observatory built by Christopher Wren in 1676 and the beginning of the Observatory under Flamsteed, the first Astronomer Royal.
        Jonathan was asked why the Time Ball was dropped at 1300 rather than at mid-day and we were told that it was because at mid-day mariners would have been occupied in many duties at that particular hour, so watching for the Time Ball’s descent was best done an hour later.  Also it turns out that the actual red ball is looking so battered, not because of pigeons flying into it but because during the 1957 restoration, no one had told the builders that it was to be re-installed, and they were just pushing it around the site, even playing football with it.  (Pretty big football…)
        In the Octagon Room we saw that the observing windows only allowed telescopes to look at a limited part of the sky, and the ceiling prevented any vertical observing whatsoever.
        Replicas of the original Tompion clocks sat in the correct positions as indicated in an early painting of the Octagon Room.  The two-second escape pendulums for them are housed above the faces of the clocks.
        On the far wall is an original Tompion clock that had found its way to Holcombe Hall in Norfolk and was purchased by the museum at a cost of £250,000.  All the other clocks and instruments belonging to Flamsteed had been sold by his wife on his death and no-one knows what happened to them.
        We descended to the floor below where Jonathan related how there had been many wrecks at sea due to the lack of any accurate method of determining longitude.  This was highlighted by the disastrous sinking of a ship under the command of Sir Cloudsley Shovel after striking rocks off the Scilly Isles in 1707 and bringing King Charles the Second to commission a method of determining longitude with Greenwich as the Prime Meridian.
        We then looked at the Harrison clocks in the new Time Gallery.  These clocks were made by Harrison in an attempt to try and win the £20,000 prize for a clock that gained or lost less than 3 seconds a day. Unfortunately, H1, the first clock built by Harrison to be used onboard ship was not on display because it was being repaired; by of all people, Jonathan Betts himself and we were to it in pieces at the end of our tour. H2 was working and Jonathan showed how the two pendulums known as anti-phase balls worked in opposition, cancelling movements as the huge clock was moved.  He also indicated the spring between the two pendulums which provided the artificial gravity. No lubrication is necessary because the clock uses roller bearings where one moving arm pivots on a bar and rocks from side to side instead of metal rubbing against metal.
        Harrison had used temperature compensation techniques where two dissimilar metals of different expansion coefficients are used to compensate the effects of temperature change on the lengths of pendulums in an ingenious frame. H3 and H4 clocks were far smaller, about 5 inches in diameter.  H4 far exceeded the terms of the act but it was just three years before Harrison’s death when he was finally awarded the prize.  These smaller clocks used lubrication and therefore need to be cleaned every three years.
        There is an H5 which is held at The Clock-Makers Guild in London.  There is also a suggestion that H6 exists but if so, no-one is aware of where it is, although Jonathan related that one had been “found” in “Only Fools and Horses”, the television series.
        Finally Jonathan took us through the rest of the Time Gallery where we were introduced to the increasingly accurate clocks that had generated the world’s time standard and produced the six pips as the broadcast time signal, although they are generated every quarter of an hour.
In all, Jonathan’s tour lasted three hours but because of his enjoyable and informative presentation non-one was aware of just how long we had taken.
        Then after lunch a bonus visit had been arranged to visit the National Maritime Museum and we were treated to a fascinating tour by Dennis Peel of craft such as the Royal Barge and to see Nelson’s Uniform – complete with shot hole.
        We saw models of the London docks from the past in incredible detail.
        It had been a full and fascinating day leaving members pretty well worn out.

SUBSCRIPTION FOR THE 2009 SESSION

        Subscriptions for the current session of Wadhurst Astronomical Society became due on the first of January.  They remain the same as previous years with adult membership at £15 and £20 for two members within the same family.  Student membership is free.
        Subscriptions can be sent direct to the Treasurer, Mike Wyles  at 31 Rowan Tree Road, Tunbridge Wells, Kent TN2 5PZ or can be paid at the meetings.
        Mike prefers to receive a cheque payable to "Wadhurst Astronomical Society" although cash is fine.

SKY NOTES FOR APRIL

Planets

Mercury is an evening object and can be found low on the western horizon after sunset at magnitude-1.5. It reaches its greatest eastern elongation on 26th April, after which it quickly disappears into the twilight to suffer an inferior conjunction on May 18th. The diagrams below explain some of the terms used here.
        This will be our best opportunity this year to see Mercury in the evening sky. Please remember that you should NEVER sweep the sky with binoculars in search of Mercury while the Sun is still above the horizon.

Venus is now a morning object in the eastern sky rising around an hour before the Sun. It shines at magnitude -4.4 although it will never be very far from the horizon.

Mars is poorly placed for observation this month.

Jupiter at magnitude – 2.2 is a morning object in the eastern sky rising an hour and a half before the Sun.

Saturn in the constellation of Leo at magnitude +0.7 is visible throughout the night. Its position is shown by the cross hair in the diagram below. Its apparent motion is very slow so this diagram will be accurate enough to find the planet for some time to come.

image

Lunar Occultations
As usual in the table I’ve only included events for stars down to around magnitude 7.5 that occur before midnight. DD = disappearance at the dark limb and RD = re-appearance at the dark limb. Times are all BST.

Apr

Time

Star

Mag.

Ph

PA °

1st

21.27

SAO 78029

7.6

DD

127

4th

20.45

SAO 98363

7.6

DD

127

6th

20.52

SAO 118530

7.2

DD

110

7th

19.48

SAO 138314

6.4

DD

137

8th

20.27

SAO 138799

6.8

DD

171

8th

22.29

SAO 138830

7.2

DD

155

8th

23.51

SAO 138845

5.5

DD

129

26th

22.32

SAO 76172

4.1

DD

44

27th

23.46

SAO 76811

7.2

DD

130

28th

20.21

SAO 77593

7.3

DD

130

29th

20.59

SAO 78855

6.8

DD

58

29th

23.35

SAO 78963

7.2

DD

142

 

Phases of the Moon for April

First
Quarter

Full

Last Quarter

New

2nd

9th

17th

25th

ISS
Unfortunately there are no passes of the ISS this month that occur before midnight. You may remember back in November last year that the astronauts servicing the ISS accidentally lost a tool bag which was not tethered and it drifted off into space. This tool bag is actually bright enough to be visible in binoculars and varies in brightness between magnitudes 5.5 and 8.0. I will include visibility timings in future if any occur at reasonable times.
 
Iridium Flares
The flares that I’ve listed are only the brightest, there are many more that are fainter, occur at lower altitudes and also after midnight. If you wish to see a complete list, go to www.heavens-above.com   Times are all BST.

Apr

Time

Mag

Alt°

Az.

5th

21.20

-6.0

20

N

6th

21.14

-5.0

22

N

8th

21.01

-7.0

26

N

10th

20.49

-4.0

30

N

11th

20.43

-4.0

32

N

12th

20.36

-6.0

33

N

13th

20.30

-7.0

35

N

14th

20.24

-4.0

37

N

26th

23.51

-6.0

32

SW

28th

22.50

-7.0

22

NE

29th

21.26

-5.0

20

N

30th

23.36

-7.0

31

WSW

Meteors
From April the 19th until the 25th the Lyrid meteor shower is active with maximum occurring on the 22nd when the ZHR will be around 10. The radiant lies a little to the west of Vega but is close to the horizon until the early hours of the morning.

Astronomical Terminology

        The diagram below explains what we mean by the terms superior and inferior conjunctions. Only Mercury and Venus (the inferior planets) can experience these because their orbits are the only ones that lie inside that of the Earth.
        Inferior conjunction occurs when the Earth, Sun and one of the inferior planets lie in a line with the planet in the middle. In very rare cases this alignment is perfect and the planet can be seen in transit across the face of the Sun. At other times it will pass either above or below the Sun and will be invisible to us.
Superior conjunction occurs when the three bodies are again aligned but with the planet on the far side of the Sun.

image

 

        Greatest Elongation is when either Mercury or Venus appears to be at their furthest from the Sun. As you can see from the diagram this does not coincide with the points when the planet will be due east or west of the Sun but occurs when the angle between the planet, Earth and Sun is 90°. The line from the Earth to the planet forms a tangent to the planets orbit and makes a right angle as shown and is generally the best time for observation. At eastern elongation the planet will be an evening object and at western elongation it will be a morning object. Rather annoyingly when inferior conjunction occurs it will be at it’s closest to us but will also have its illuminated face turned away from us.

image

        I said earlier that superior planets don’t suffer superior and inferior conjunctions (in the way that Mercury and Venus do) but they do still go through a conjunction when they pass behind the Sun as seen from Earth. At other times they can be in opposition which occurs when the Sun, Earth and the planet are in line but with the planet on the opposite side of the Earth to the Sun. This would be an ideal time for observation because the planet will be at it’s closest to us.

image

Brian Mills

NASA SPACE PLACE

Apollo Upgrade

        The flight computer onboard the Lunar Excursion Module, which landed on the Moon during the Apollo program, had a whopping 4 kilobytes of RAM and a 74-kilobyte “hard drive.” In places, the craft’s outer skin was as thin as two sheets of aluminium foil.
It worked well enough for Apollo. Back then, astronauts needed to stay on the Moon for only a few days at a time. But when NASA once again sends people to the Moon starting around 2020, the plan will be much more ambitious—and the hardware is going to need a major upgrade.
        “Doing all the things we want to do using systems from Apollo would be very risky and perhaps not even possible,” says Frank Peri, director of NASA’s Exploration Technology Development Program.
        So the program is designing new, more capable hardware and software to meet the demands of NASA’s plan to return humans to the moon. Instead of staying for just a few days, astronauts will be living on the Moon’s surface for months on end. Protecting astronauts from harsh radiation at the Moon’s surface for such a long time will require much better radiation shielding than just a few layers of foil. And rather than relying on food and water brought from Earth and jettisoning urine and other wastes, new life support systems will be needed that can recycle as much water as possible, scrub carbon dioxide from the air without depending on disposable filters, and perhaps grow a steady supply of food—far more than Apollo life-support systems could handle.
        Next-generation lunar explorers will perform a much wider variety of scientific research, so they’ll need vehicles that can carry them farther across the lunar surface. ETDP is building a new lunar rover that outclasses the Apollo-era moon buggy by carrying two astronauts in a pressurized cabin. “This vehicle is like our SUV for the Moon,” Peri says.
        The Exploration Technology Development Program is also designing robots to help astronauts maintain their lunar outpost and perform science reconnaissance. Making the robots smart enough to take simple verbal orders from the astronauts and carry out their tasks semi-autonomously requires vastly more powerful computer brains than those on Apollo; four kilobytes of RAM just won’t cut it.
        The list goes on: New rockets to carry a larger lunar lander, spacesuits that can cope with abrasive moon dust, techniques for converting lunar soil into building materials or breathable oxygen.  NASA’s ambitions for the Moon have been upgraded. By tapping into 21st century technology, this program will ensure that astronauts have the tools they need to turn those ambitions into reality.
        Learn more about the Exploration Technology Development Program at www.nasa.gov/directorates/esmd/aboutesmd/acd/ technology_ dev.html.
        Kids can build their own Moon habitat at spaceplace.nasa.gov/en/kids/exploration/habitat.

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

Any material for inclusion in the May 2009 Newsletter should be with the Editor by 28th April 2009

 

CONTACTS

ChairmanJohn Vale-Taylor
TreasurerMike Wyles 01892 542863
EditorGeoff Rathbone01959 524727
EventsPhil Berry01892 783544
Sky NotesBrian Mills01732 832691
Wadhurst Astronomical Society website:
SAGAS web-site