WADHURST ASTRONOMICAL SOCIETY

OCTOBER NEWSLETTER 2007

INDEX: MEETINGS, OTHER NEWS, CONTACTS

MEETINGS

COMMITTEE MEETING

Members of the Society's Committee are respectfully reminded that there is meeting of the Committee on Monday the 8th of October at the Abergaveny Arm, Frant starting at 1930.

As always any full member of the Society is encouraged to come along and join in, make suggestions, give opinions or just have a drink.  The Committee do appreciate members' interest and you will not be "press-ganged" into joining the Committee.

SEPTEMBER MEETING

How to Control a Telescope Remotely

Talk given to the September meeting by Dr Lilian Hobbs

Lilian Hobbs is a Project Manager with the Oracle Corporation and is also President of the Southampton Astronomical Society from where she had travelled to give this evening's talk.  During his introduction Phil Berry explained that Lilian had agreed to talk to us at the last minute owing to an unexpected business commitment by our original speaker.

Lilian began by suggesting that astronomy in the warm on a cold winter's evening offered a number of advantages but that this presented a number of challenges in achieving a working system that didn't cost too much.

One of the methods would be to use cables to control a telescope but these would be vulnerable and the distance could be too far for satisfactory use.  A suitable solution might be to use a computer to control the telescope and this could also be used to make images using a CCD camera.  But in the case of Lilian's garden the distance was 150 feet and this was still a long way.

The story of Lilian's project began back in 2000, when, by following her shares on the financial markets, the time seemed right to cash them in and with the added help of "Hector" of Inland Revenue fame the money became available to finance a small observatory.  She considered various structures.  The most practical would be a BCF dome but later decided on a 7-foot diameter Pulsar dome which duly arrived on the back of a lorry, already assembled and only had to be lifted into its final position.

The telescope was a 12-inch LX200.  A tripod took up too much floor space so a pillar was erected in the centre.  Later Lilian replaced the telescope with a 14-inch AP1200 but later still sold it and bought a TMB 7-inch telescope and Astro-physics 4.74-inch telescope on a Paramount ME mount that she considers to be accurate to less than a pixel with the result that a finder was not necessary on the telescopes.

Now control of the telescopes needed consideration.

Lilian's solution was to use two computers and link them together by means of network working.  As she suggested, many of us have an old computer tucked away somewhere after they have been replaced with something more up-to-date.  This is usually and old one but is quite suitable to use at the telescope end.  Another consideration was whether to use cable or wireless.  It was felt that wireless was too vulnerable and slow and the distance was too far, so industrial standard cable was the answer.  The right length arrived on her desk one day when the remains of a drum were about to be discarded after some rewiring had been done.

The power and the network cable are fed from the warmth of the house through separate hosepipes to the cold of the dome.  Using the networked computers, Lilian is able to focus and move her telescope and use a CCD still or video camera.  Two things that have to be done by visiting the dome in person are to align the telescope when necessary and to turn the roof of the dome, although the latter might be possible but a lot more expensive.

One problem was dampness in the dome and it was found necessary to use a dehumidifier -remembering to empty out the water before it got too full!

Then came the control system.  Lilian uses Maxim software but prefers PC-Anywhere, which she says, makes any remote computer look local even if it is on the other side of the world.  Also mentioned was VNC software, which is free.  VNC is popular but is not as fast as PC-Anywhere.

Using these remote controlled systems it is even possible to use a small telescope just outside and then a wireless connection could be used.

One word of warning.  The telescope can be left to do its stuff but needs an eye kept on it to prevent accidents such as attachments falling off or being driven into something and catching cables.  Lilian uses a small infrared security camera that can be monitored on the network and has the advantage that it doesn't need a light that could affect viewing contrast.  Even so, it can start raining whilst the telescope is still looking at a clear part of the sky.

Various systems of remote focussing were tried such as the JMI NGF-S motor focus and Robofocus.  We were told that it was best to begin trying out the focussing method during the day on such things as pigeons on TV aerials and then slowly to extend the distance to eventually reach infinity.

Accurate time is also required and a radio clock was found to be ideal, although those with GPS systems have one of the most precise sources of time.

To process images, Registax, which is free, can be used.  Processing can be done on cloudy nights, during the day or even when travelling with a laptop on a plane, which Lilian has done on occasion whilst flying to the USA (and unexpectedly found herself sitting next to a professional astronomer from Lowell observatory!).

More recently Lilian has been using a TV85 and LX200 for wide field observing.

One exciting thought was suggested that uses the internet to operate telescopes belonging to willing amateurs thousands of miles away such as the west coast of the United States where observers would be going to bed during our daylight hours.

Lilian ended her talk by showing a number of images she had made such as M31, the Dumbbell nebula and a superb image of the Horse Head nebula.

After a large number of questions Lilian headed off back to Southampton having given an excellent talk.

FUTURE MEETINGS & EVENTS

Wednesday 17th October 2007  Keith Brackenborough will be giving a talk with the intriguing title "The Calendar - A 5,000 year struggle  to Align the Clock to the Heavens".

Wednesday 21st November 2007  Details to be announced.

Wednesday 12th December 2007  NOTE: THIS IS THE SECOND WEDNESDAY OF DECEMBER   Society Member, Paul Treadaway is giving a talk he calls "Why are we Still Here?" - Food for thought...

GO TO INDEX

OTHER NEWS  

SOCIETY VISIT TO BELMONT HOUSE

On Saturday the 22nd of September the Society visited Belmont House deep in the Kent countryside to have a guided tour of the finest private collection of clocks in Britain.

Jonathan Betts, the Curator of Horology at the National Maritime Museum at Greenwich, took us on a fascinating journey through the world of clocks.  One German clock dating back to the sixteenth century.

The Collection was the lifetime achievement of the fifth Lord Harris and numbered well over three hundred, although only half of them could be displayed at one time.  Even so, Jonathan brought out one or two clocks that had particular astronomical relevance such as an orrery clock.  Another was a beautiful pendulum clock displaying the Equation of Time.

There were fine examples of Tompion and also Knibb longcase clocks and Jonathan Betts let us into some of the secrets of terminology in the clock world.

Originally, Knibb introduced clocks that had the "IV" instead of the usual "IIII" on the dial (not "face") denoting that the clock had Roman striking (not "chiming").  A "ding" from a high bell indicates each "I" and a "dong" from a low bell denotes the roman "V".  Two blows from the low bell indicate "X" - ten!  This system was introduced to reduce the drive force required.

Jonathan also opened a number of clocks to show the incredibly fine work used in the movement (not "mechanism"), also revealing how even the innermost parts were covered in beautiful designs.

The "novelty room" had a French made clock although retailed in Birmingham, with a singing bird automaton dating from around 1880.  The birds appeared to hop from branch to branch whilst singing.

The tour lasted well over two hours and was extremely impressive.

SKY NOTES FOR OCTOBER

Planets

Mercury will not be observable as it passes through inferior conjunction on the 23rd.

Venus is a brilliant morning object at magnitude -4.5 in the constellation of Leo (the lion). On the 9th of October it passes 3° south of Regulus, and on the 14th it passes 3° south of Saturn.

Mars in the constellation of Gemini (the twins) continues to brighten to magnitude -0.6. By the middle of the month it rises before 22.00 BST.

Jupiter is still visible low down in the west after sunset at magnitude -1.9 in the constellation of Ophiuchus (the serpent bearer).

Saturn is a morning object at magnitude 0.7 in the constellation of Leo.

Lunar Occultations

Below are the events involving reasonably bright (down to about mag 7.5) stars that occur before midnight. DD = Disappearance on the Dark limb, RD = Reappearance on the Dark limb and DB = Disappearance on the Bright limb. The occultation of Regulus on the 7th could be worth watching, particularly to see it "pop out" from behind the dark limb of the waning crescent moon. Times are all BST with the exception of the last one.

Meteors

Between the 16th and 21st of this month one of the less active meteor showers ( the Orionids) occurs with it's maximum on the 20th. Unfortunately the radiant which lies close to the star Betelgeuse doesn't rise until 22.30 BST. However, on the plus side the meteors tend to be fast and bright and often leave ionised trails which can persist for a few seconds.

Comet C/2007/F1 (LONEOS)

This is a comet that was found in the early part of the year and has since been imaged at magnitude 11 which is brighter than expected. It is thought that it will become an easy binocular object at magnitude 5 to 6 towards the end of October. On the nights of the 20th and 21st it will lie just south of the bright star Arcturus in Bootes (the herdsman).

ISS

There are plenty of opportunities to see the ISS this month. Below are listed just the most favourable with respect to elevation and magnitude. Times are BST. For more details log on to the web-site: - www.heavens-above.com

Don't Forget

British Summer Time ends on Sunday 28th October at 02.00 hrs. 

Advance Notice

The Leonids maximum occurs on November 18th in the early hours of the morning.

I know it's a long way off but did you know that the International Astronomical Union (IAU) has designated 2009 as the International Year of Astronomy. It marks the 400th anniversary of Galileo first turning a telescope towards the sky.

Brian Mills

NASA SPACE PLACE

A Missile in Your Eye

by Patrick L. Barry

Satellite technology designed to catch ballistic missile launches may soon help doctors monitor the health of people's eyes.

For the last 15 years, Greg Bearman and his colleagues at JPL have been working on a novel design for a spectrometer, a special kind of camera often used on satellites and spacecraft. Rather than snapping a simple picture, spectrometers measure the spectrum of wavelengths in the light coming from a scene. From that information, scientists can learn things about the physical properties of objects in the photo, be they stars or distant planets or vegetation on Earth's surface.

In this case, however, the challenge was to capture snapshots of short-lived events-like missile launches! The team of JPL scientists designed the new spectrometer, called a computed tomographic imaging spectrometer (CTIS), in collaboration with the Ballistic Missile Defense Organization as a way to detect missiles by the spectral signatures of their exhaust.

But now the scientists are pointing CTIS at another fast-moving scene: the retina of an eye.

Blood flowing through the retina has a different spectral signature when it is rich in oxygen than when it is oxygen deprived. So eye doctors can use a spectrometer to look for low oxygen in the retina-an indicator of disease. However, because the eye is constantly moving, images produced by conventional spectrometers would have motion blurring that is difficult to correct.         

The spectrometer that Bearman helped to develop is different: It can capture the whole retina and its spectral information in a single snapshot as quick as 3 milliseconds. "We needed something fast," says Bearman, and this spectrometer is "missile-quick."

CTIS is even relatively cheap to build, consisting of standard camera lenses and a custom, etched, transparent sheet called a grating. "With the exception of the grating, we bought everything on Amazon," he says.

The grating was custom-designed at JPL. It has a pattern of microscopic steps on its surface that split incoming light into 25 separate images arranged in a 5 by 5 grid. The center image in the grid shows the scene undistorted, but colors in the surrounding images are slightly "smeared" apart, as if the light had passed through a prism. This separation of colors reveals the light's spectrum for each pixel in the image.

"We're conducting clinical trials now," says Bearman.  If all goes well, anti-missile technology may soon be catching eye problems before they have a chance to get off the ground.

Information about other NASA-developed technologies with spin-off applications can be found at:

http://www.sti.nasa.gov/tto

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

GO TO INDEX

CONTACTS

Chairman   John Vale-Taylor  pjvalet@tiscali.co.uk

Phil Berry  01892 783544 phil.berry@tiscali.co.uk

Treasurer  Mike Wyles  01892 542863 mikewyles@globalnet.co.uk

Publicity & Website  Michael Harte  01892 783292 was@greenman.demon.co.uk

Newsletter Editor  Geoff Rathbone  01959 524727 Geoff@rathbone007.fsnet.co.uk

Any material for inclusion in the November Newsletter should be with the Editor by October 28th  2007

GO TO INDEX