LECTURE ON CLIMATE CHANGE

        At our October meeting, Society member Jan Drozd announced that there is to be a talk by one of the foremost climate scientists in the UK .

        Professor Andrew Watson’s talk is called “Is the Earth’s Climate Changing? - Are humans causing it? – Should we be bothered?” and follows on from Jan’s own talk to us recently.

        The talk is free and is at Pamoja Hall, Sevenoaks School starting at 1900 on Wednesday the 2nd of November.

        There is free car parking directly outside Pamoja Hall.

        It is not necessary to book but the hall is limited to 450 people so early arrival might be a good idea.  www.sevenoaksschool.org/

MEETINGS

THE OCTOBER MEETING

        The October meeting was led by Phil Berry who introduced the main talk of the evening.

Point Your Granny’s Box Brownie at the Stars

Brian Mills

        Brian showed some images taken by amateurs which can be favourably compared with those taken by professional astronomers using modern techniques, but he explained that his talk tonight looks at more modest methods of deep sky imaging using just a Digital Single Lens Reflex camera and stacking the imagers together.

An example of a DSLR camera

        First we looked at what is needed:

¯       A DSLR camera

¯       A tripod

¯       Some kind of exposure release mechanism.

        Then we looked at the advantages and disadvantages of film compared with digital cameras.

        Although film tends to have more red sensitivity it has a lower dynamic range, CCDs in digital cameras are more sensitive overall and can have higher resolution.  One major advantage of digital cameras is the convenience of being able to immediately review the results so that adjustments can be made.

        The DSLR camera needs to be capable of exposures of at least 30 seconds and have some kind of remote shutter release that doesn’t shake the camera during exposure time or, as Brian mentioned, one solution is a “black hat” as used in the very early days of photography when film was slow and needed very long exposure times.  A black hat is held in front of the lens and once the shutter is open and the camera has stopped shaking, the hat is removed for the duration of the exposure and then place in front again whilst the shutter is closed.

        Live view has the advantage of allowing focus to be checked on a bright star.

        Brian suggested saving images as RAW format if possible because this contains the greatest amount of unprocessed data.  The big disadvantage though is the huge file generated compared with TIFF and JPEG files.

        The tripod needs to be sturdy.  At this point Brian compared a couple of tripods; one costing less than £35 and one costing an enormous £500 with another £500 for the head!  Apart from stability it is important that the tripod can allow the camera to look in any direction of the sky.

        Various shutter release methods were described; infra-red remote (which usually operates from the front of the camera and can be a problem of access), wireless remote and connection to a PC.

        One computer programme that enabled the camera to be set and also controlled the shutter release for as long as is needed is EOS 400D Digital.  Another is APT – Astro Photography Tool and costs around £5 but this will allow everything to be scheduled for the evening and once set up the whole thing can be left to carry on.

        Next Brian mentioned filters and showed an image he had taken from his back garden, showing the “W” in Cassiopeia, first without a filter and then a much clearer image taken using a pollution filter,.  The light glow disappeared but the exposure had to be increased to compensate. A good filter being a neodymium filter

        Tracking was briefly was talked about.  Nearer the equator, the stars appear to be moving much more rapidly than they do towards the pole and if longer exposures are being made, some kind of tracking may be required.

        A couple of things worth remembering before imaging begins are making sure that there is enough battery charge left and there enough memory space left on the camera card.  Also, wrapping the neck strap round the tripod is a good safety measure.

        Now Brian moved on to taking images with the camera.  He suggested beginning with as short a focal length as possible, reducing the movement of that part of sky being photographed.  Reducing the stop by just one stop will reduce distortion caused by not using the edge of the lens where any distortion would be.  The camera will probably be unable to auto-focus so manual focus will be necessary.

        He recommended setting the camera to manual taking a short 10” to 15” exposure of a bright star with the lens set to infinity focus.  It will be necessary to take several trial exposures because infinity marked on the lens is rarely accurate enough.  Magnify the image to check focus helps even more.

        Direct the camera to that part of the sky you want of image.  It may be possible that you can’t see anything, but take as many exposures as you think you need.  Brian had taken a number of 25” exposures to illustrate his talk.

        To demonstrate the use of Deep Sky Stacker already loaded on his laptop Brian projected the display on his computer onto the main screen.  The freeware programme had been previously downloaded from:

http://deepskystacker.free.fr/english/index.html

        He then loaded into the programme several images he had taken recently of the area around the “W” in Cassiopeia.  In each one, virtually nothing was discernable apart from the main brighter stars but after the programme had registered the individual images using the visible stars, the stacked result began to show much fainter objects and slowly we began to to make out the Great Andromeda Galaxy M31.  On the laptop screen it was even possible to see a hint of the Milky Way.

        For this occasion Brian said he had used JPEG images and not used dark or flat exposures just to save time or it would have taken all evening to demonstrate using his laptop computer.

        After a while he used Photoshop to enhance the image.  The detail was not great but as Brian said, this was after using just four 25” exposures and looking at any individual frame there was no hint of the galaxy.

        Using many more frames, perhaps as many as 60 and experimenting with tighter lenses it had been demonstrated that with just a DSLR it was possible to reveal quite satisfying deep sky objects.

Unusual observations from the scientific world

John Wayte

        In July John mentioned that the coolest star known was a mere 100o C.  He has since learnt of a new star discovered by WISE (Wide Field Infrared Survey Explorer).  It is a brown dwarf with an incredibly low temperature of just 25o C and is in the constellation of Lyra.

        It has also been announced that Ionised gas has been discovered in our own Milky Way and it is estimated that this is sufficient to produce one new star per Earth year.  Also substantial gas found within the Milky Way’s halo (40,000 light years) means that more stars will form in our own back yard… eventually.

        John has found a very interesting website whose data allows one to follow NASA spacecraft as they fly by the planets in our solar system.  He says it is like sitting on the shoulders of the spacecraft as they wiz from planet to planet, using actual footage as it was recorded.  It is quite a deep programme with many facilities but is well worthwhile having a look at.  It is called “Eyes on the Solar System” and is at: http://solarsystem.nasa.gov/eyes

A data recording method for use when observing Occultations  Phil Berry

        The Society has an Occultation ring as members may be aware following a number of references made recently at meetings and Phil Berry introduced some methods used to observe the moon as it passes in front of certain stars.

        Very precise timings are required to be of any use to the organisation who collates data from all around the world.

        To show basic aids, Phil used his 5 NextStar telescope.

        Telescopes often have to be set up during daylight and to help find a star Phil uses a previously lined-up green laser to point to the star which should then been seen in the finder.  He uses a finder with an off-axis cross illuminator.

        A flip mirror box is used to first line up on the star and then the mirror is positioned out of sight to allow the star to be seen directly by Phil’s Watec CCD camera which can record up to 60 frames a second.

        Using a Video Text Overlay unit connected to a GPS, the exact position and time is overlaid on to every image.

        Phil uses a very small video recorder no bigger than a mobile phone to record the final images.

        Par-focus is used so that once the telescope is focussed as seen through the finder; it is also set correctly for the Watec camera once the mirror is flipped out of the way.

        The whole of Phil’s system runs off a small 12 volt battery pack which he says can last him about 7 hours.

        All this equipment means that it is necessary to rebalance the whole telescope before preparing for an occultation but the results should be very accurate.

NOVEMBER MEETING

        Wednesday 16th November 2011 – David Mannion talks to us about “Galileo and 400 years of Telescopic Astronomy” in which he also looks at the future of astronomy. 

        David has three degrees in astronomy and has been a teacher for 24 years.  He is also co-writer of a book of the same title as his talk and will have copies available to buy at the meeting.

        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 also 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)

        Anyone is welcome.  Non-members are asked to contribute £2.

FUTURE  MEETINGS

        Wednesday 21st December 2011 – This is our Christmas meeting when Paul Treadaway will present a talk called “The Theory of Relativity”.  Paul is one of our own members and has spoken on a number of topics before.

        There will also be mince pies to have with coffee and tea.

Please note – the date for the December meeting in the October Newsletter was incorrect.

        Wednesday 18th January 2012 – January is the month when we hold the Society’s Annual General Meeting.  This is then followed by a talk by Dr. Bob Seaney called “The Multiverse Universe” during which Bob introduces us to an exciting look at the Universe.

OTHER NOTES AND INFORMATION

SKY NOTES FOR NOVEMBER

Planets

Mercury is an evening object but is sadly not visible from these latitudes.

Venus suffered a superior conjunction in August and will only reappear in our evening skies at the very end of the month. It continues to pull away from the Sun until March 27th 2012 when it reaches greatest eastern elongation at magnitude -4.2.

Mars is just about an evening object, rising as it does a few minutes before midnight at the start of the month. By the end of November it still only rises at 2320 because of its retrograde motion.

Jupiter at magnitude -2.9 is in Aries and visible throughout the hours of darkness. It is currently moving retrograde (east to west) and will continue to do so until Boxing Day when it will have reached its second stationary point just over the border in Pisces. It is unmistakeable in the south east, and by the end of the month it is on the meridian around 2100. Binoculars, providing that they are mounted on a tripod or other stout support, will show the four Galilean moons.

Saturn is a morning object in Virgo at magnitude +0.7. By the end of the month it rises at 0345, although it will be the beginning of February next year before it rises ahead of midnight.

Lunar Occultations

In the table below I’ve 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 at more unsociable hours.  DD = disappearance at the dark limb and RD = reappearance at the dark limb.

Times are in GMT.

Nov.

Time

Star

Mag.

Ph

PA °

6th

2217

SAO 128487

6.9

DD

15

13th

2152

SAO 77358

6.4

RD

265

15th

2149

SAO 96888

6.9

RD

255

29th

1811

SAO 163612

6.4

DD

131

Phases of the Moon for November

First ¼

Full

Last ¼

New

2nd

10th

18th

25th

ISS

There are very few passes visible before midnight this month as most occur in the early morning. The details of all passes including those visible from other areas can be found at:

 www.heavens-above.com

Please remember that the times and directions shown below are for when the ISS is at its maximum elevation, so you should go and look a few minutes before. Times are in GMT.

Nov.

Mag

Time

Alt°

Az.

1st

-3.2

1709

74

SSW

3rd

-2.7

1649

54

SSW

Iridium Flares

The flares that I’ve listed are magnitude -4 or brighter although there are a lot more that are fainter, occur after midnight or at a lower altitude. 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 sometimes 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.

3rd

1727

-5

41

S

7th

1712

-4

36

S

9th

1835

-8

41

SE

11th

1657

-7

32

SSW

14th

1814

-8

40

SSE

17th

1639

-6

23

SSW

19th

1636

-4

20

SSW

21st

1634

-5

16

SW

21st

1724

-5

14

WNW

22nd

1709

-6

17

WNW

23rd

1723

-4

20

WNW

23rd

1738

-4

35

S

25th

1633

-6

24

W

27th

1612

-6

28

W

27th

1723

-5

32

S

Meteors

The Draconids - Sadly last month’s show was clouded out for a large part of the UK but in the areas (here and abroad) where observations were possible, a ZHR (zenithal hourly rate) of approximately 350 was recorded.

The Taurids - This shower is active from October 20th until November 30th with a broad maximum lasting from the 5th to the 12th of this month. The reason for the length of activity is that the stream of material is so large - in fact one of the largest in the solar system. Comet Encke is responsible for the shower although it is thought that both the comet and the meteor shower are the remnants of a much larger comet. In 2005 there was enhanced activity and a large number of fireballs were seen. The ZHR is only around 10, but there have been outbursts in previous years so a watch is always worthwhile. The diagram shows the location of the radiant by the circled letter “R”. You do not have to watch the radiant, it is simply the point that meteors appear to come from if you trace them backwards.

The Leonids - This shower is associated with the comet 55P/Tempel-Tuttle and is active from November 15th until the 20th with maximum occurring in the early hours of the 18th. These are very fast meteors that often leave an ionised trains. The shower has suffered outbursts in the recent past although nothing out of the ordinary is forecast this year. The radiant, as shown in the diagram, rises at around 2230 on the night of maximum.

The Night Sky in November (Written for 2200 GMT mid month)

In the north Cassiopeia is close to the zenith whilst Ursa Major is just starting to climb away from the horizon. Below Cassiopeia is the fainter constellation of Cepheus that is well positioned for identification.

In we look east the bright winter constellations are now appearing. Auriga, Gemini, Taurus and Orion are all now visible, though the “Dog Star” - Sirius - has not yet risen.

In the south, even though Pegasus has passed the meridian, the constellations that lie below it - Pisces, Cetus and Aquarius are still easily visible though the bright star Fomalhaut is right on the horizon.

In the west, of the bright stars of the summer triangle, Altair has almost set but Vega and Deneb are still very much on show.

Advanced warning for December

Eclipse - There is a total lunar eclipse on December 10th although totality is over by the time of moonrise in the UK .

Geminids - This is one of the best shows of the year with maximum occurring on the 14th. A waning gibbous Moon rises at 2015.

DEFINITIONS OF TERMS USED IN ASTRONOMY

(Some meteor related ones this month).

Fireball - It depends which definition of fireball you prefer, but according to the IAU (International Astronomical Union) it is any meteor that exceeds magnitude -4 in brightness. However the IMO (International Meteor Organisation) says that it is a fireball if its magnitude is -3 or greater when seen at the zenith. This means a fainter meteor seen near the horizon could be classed as a fireball when extinction is taken into account.

Altitude °

Extinction in magnitudes

1

3

4

2

10

1

16

0.5

43

0.1

Over 45°

No effect

Bolide - Although the IAU has no formal definition of the word, it is generally accepted that a meteor can be classed as a bolide when it reaches a magnitude of -14.

Superbolide - refers to meteors that reach a magnitude of -17.

Ionised Train - This is the faint line that remains after a meteor has been seen and is caused during the passage of the particle through the upper atmosphere. Most are visible for a second or less but some remain for many minutes.

Brian Mills

NASA’S SPACE PLACE

The Gray Cubicle You Want to Work In

By Dr. Tony Phillips

        It's another day at the office.

        You're sitting in a gray cubicle, tap-tap-taping away on your keyboard, when suddenly your neighbour lets out a whoop of delight.

        Over the top of the carpeted divider you see a star exploding on the computer screen. An unauthorized video game? No, this explosion is real. A massive star just went supernova in the Whirlpool Galaxy, and the first images from Hubble are popping up on your office-mate’s screen.

It's another day at the office ... at NASA.

        Just down the hall, another office-mate is analyzing global temperature trends. On the floor below, a team of engineers gathers to decode signals from a spaceship that entered “safe mode” when it was hit by a solar flare. And three floors above, a financial analyst snaps her pencil-tip as she tries to figure out how to afford just one more sensor for a new robotic spacecraft.

These are just a few of the things going on every day at NASA headquarters in Washington DC and more than a dozen other NASA centres scattered around the country. The variety of NASA research and, moreover, the variety of NASA people required to carry it out often comes as a surprise. Consider the following:

        NASA's Science Mission Directorate (SMD) supports research in four main areas: Earth Science, Heliophysics, Astrophysics, and Planetary Science. Read that list one more time. It includes everything in the cosmos from the ground beneath our feet to the Sun in the sky to the most distant galaxies at the edge of the Universe. Walking among the cubicles in NASA’s science offices, you are likely to meet people working on climate change, extraterrestrial life, Earth-threatening asteroids, black holes or a hundred other things guaranteed to give a curious-minded person goose bumps. Truly, no other government agency has a bigger job description.

And it’s not just scientists doing the work. NASA needs engineers to design its observatories and build its spacecraft, mathematicians to analyze orbits and decipher signals, and financial wizards to manage the accounts and figure out how to pay for everything NASA dreamers want to do. Even writers and artists have a place in the NASA scheme of things. Someone has to explain it all to the general public.

      Clearly, some cubicles are more interesting than others. For more information about the Science Mission Directorate, visit science.nasa.gov. And for another way to reach the Space Place, go to:

http://science.nasa.gov/kids.

Some of the employees of NASA’s Science Mission Directorate may work in gray cubicles, but their jobs are anything but dull. They get to study Earth, the Sun, the Solar System, and the Universe!

CONTACTS

Chairman     John Vale-Taylor

                                                      pjvalet1@btinternet.com

Secretary & Events                 Phil Berry             01892 783544

                                                      philberryemail@gmail.com

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

Paul Treadaway                       01342 313799

                                                      paul_treadaway@btinternet.com

Wadhurst Astronomical Society website:

                                                      www.wadhurst.info/was/

SAGAS web-site                        www.sagasonline.org.uk

Any material for inclusion in the December 2011 Newsletter should be with the Editor by November 28th 2011