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Highlands Astronomical Society

Stargazey Pie January 2006

New Year, same old weather! After the January 2005 meeting some members had severe difficulties getting home because of the storms, and some didn’t make it at all! Thankfully the strong winds we heard during January 2006’s meeting had mostly blown themselves out by the end. There was a very large turnout for the first meeting of 2006, with plenty going on to hold everyone’s attention, including some changes to the observing schedule, a great talk from Arthur Milnes, and a nice shiny new telescope brought along by Allan Thorne. Before these highlights were revealed the notices were read out by Chairwoman Pauline Macrae, fresh from her New Year revels (or were they Maltesers…?).

  • Observing Sessions. Operation ‘Observing 2006’ is up and running, as January’s observing sessions were announced. They start at 8pm, weather permitting, and continue until 11pm on the dates below. If the weather is good they will be on, but if in doubt please phone the contactbefore 7.30pm, or their mobile number after 8pm. Telephone numbers are on the Contact phone list. It is proposed that the number of observing weekends each month is increased this year, but it will depend on increased support for these sessions by the membership. As well as weekends when the Moon is absent or young, weekends with a Moon at about first quarter will now be utilised as well, and there is even the possibility of sessions being run on weeknights. Again, it all depends on what the members want and will use. The man to contact about this is David Hughes, who has taken on the organisation of the observing team.

Friday 20th Jan....Pauline Macrae
Saturday 21st Jan....Les Gamble
Friday 27th Jan....Antony McEwan
Saturday 28th Jan....Trina Shaddick

  • Astrofest 2006! The event known throughout the galaxy as Astrofest 2006, held by Astronomy Now magazine, will take place on Friday 3rd and Saturday 4th February. After glowing reports from Pat Williams, Pat Escott and Linda Moncur who went last year, several members are already booked to go this time round, including the two Pats and our illustrious Chairwoman. Tickets are available online here, but be warned- the accommodation is quite expensive as the event does take place in London, the most expensive city in the Orion Arm.
  • New Year, New Horizons. The launch of NASA’s New Horizons mission to Pluto and beyond will take place on Tuesday 17th January between 18:24 and 20:23 GMT. The launch will be broadcast on NASA Online TV, so be sure you watch it online if you are able! Two days earlier the Stardust mission is due to return to Earth around 10:12 GMT, carrying its precious cargo of comet-dust. Let’s hope it fares better than the Genesis mission that suffered rather a bumpy landing when its parachutes failed to deploy properly.
  • Local Astronomy Course. Maarten is running an astronomy course in the Victoria Hall, Cromarty, which will take place over four Thursday evenings, starting on Thursday 16th February. It will use the ‘Philips Guide to the Stars and Planets’ as course material, and will cover all the subjects contained therein but not in too much detail. Observation sessions will follow the lessons but will depend on the weather. It is hoped that the course will finish with a live session on the Faulkes Telescope on Saturday 11th March. This would be highly preferable to a dead session on the telescope. The signing up day for enrolment will be Saturday 21st January in Cromarty between 11:00 am and 2:00 pm, also in the Victoria Hall.
  • Mmm…chocolate. Pauline expressed many thanks to everyone who donated raffle prizes last month, and to Tom and Danielle Hunt who took along a big tin of chocolates, some of which were still available at this meeting. There definitely won’t be any left at next month’s though. Pauline also explained that while Office Bearers are supposed to be immune to bribery by chocolate, it never hurts to try, as you just never know…

Blue Moons and Big Eyes.

After the notices, Pauline referred back to December when there were two new moons in the month. In December she asked what such an event would be called, and at this meeting quoted examples of Spinner’s Moon, Secret Moon, Black Moon and Finder’s Moon, some of which seem to have been suggested especially for this phenomena as a result of an online poll. Amazing how modern folklore is created! Of course reference was made to the Blue Moon, which is what most people now think of as the second full moon within any calendar month. Pat Williams and Maarten disagreed with this definition though, saying that this ‘misunderstanding’ came about through a misprint in an astronomical magazine many years ago. I had heard this too, but nevertheless this has come to be what most people now recognise as a ‘Blue Moon’.

Well, this month the debate continued, but no real progress was made. The Blue Moon argument waxed and waned, with no definite confirmation of the true definition of the phenomenon, though Maarten did continue to remind everyone present that they were all wrong. ;-) Hopefully some final answer to this will come at the next meeting. (Maarten did say he would seek out further information, but in the meantime I found this page very informative.)

Pauline’s question for this meeting was, “What is Dark Adaption or Dark Adaptation”? The answers that came from the membership included pupil dilation, chemical changes to the eye and preparation of the eye for darkness. All of which are sort-of correct, but Pauline explained in more detail that while pupil dilation is a response that happens immediately the eye is subjected to darkness, dark adaption takes much longer as it is actually a chemical process that occurs in the visual receptors at the back of the eye. There are two types of receptors: rods and cones. The rods are sensitive to dim light and are responsible for our night vision, allowing us to see the faint fuzzy objects we seek out in our telescopes and binoculars.

During dark adaption, the chemical within the rods regenerates after being bleached by daylight or other strong light and this process can take 20 to 30 minutes or longer. This is also the reason why white light at night can instantly obliterate your dark-adaption, and is why we should all have a red light source for reading maps, writing observations etc when our eyes are dark-adapted.

The cones, on the other hand, give us our colour perception, and are used during the day and under bright light. They are concentrated in the fovea - that part of the retina that is used for detailed vision; things like reading, sewing, watching TV, typing up newsletters on the computer- everyday sorts of things. Since the fovea contains only cones, we cannot look directly at a faint object at night but by using averted vision this allows the rods to come into play. However, the cones can be useful to detect fine details when looking at the planets, which are bright objects.

It was interesting to hear the processes involved being explained in a manner that was easily understood. Thanks Pauline- what’s next month’s question?

Eyes on the Skies.

So far we've had some pretty good skies to 'see 2006 in'. January has the winter constellations well placed, giving observers access to open clusters, planetary nebulae, globular clusters, supernova remnants, emission nebulae, galaxies- you name it and it's there to be seen somewhere in January's sky.

The brightest and easiest of these to find will be the traditional 'highlight' objects; things like the Eskimo planetary nebula and open cluster M35 in Gemini, emission nebula M42 (and others) in Orion, supernova remnant M1 in Taurus, the Beehive cluster M44 in Cancer, M45 Pleiades in Taurus, the Leo galaxies etc- a long list of objects that are easily found and oft-looked at. Excellent targets, but one of my resolutions this year was to look harder. By that I mean that once I'm lined up on these objects I'll try to spend more time observing them, trying to see more of what's there rather than taking a quick look and moving on to the next on the list.

So for classic galaxies like M81 and M82 in Ursa Major, I'll try using different magnifications and using averted vision by directing my eye to different areas of the edge of field to see which 'direction' my peripheral vision is most effective in. I'll refer to my star-chart books to find out more information about the objects after I've located them, and see if I can spot any details mentioned in the text.

I'll also seek out new life I mean new targets that I haven't ever seen before- there are plenty of them after all! I'll try to hunt down some NGC galaxies or really faint nebulae, like the other night when I managed to find NGC 891, an edge-on spiral galaxy in Andromeda. It's listed as being magnitude 10, well within the reach of even a 4" telescope, but in my 8" Dobsonian it took a lot of finding because the surface brightness is spread out over a long thin area. It's very satisfying when you find a new object for the first time! Here is the image of it taken by the imaging team at the Going Nova event, using the Faulkes Telescope.

If you want to gain more from your viewing sessions, maybe some self-imposed observing challenges like these would be helpful for you as well?

Planet-wise, Mars is becoming more distant (though surface detail is still visible) and Saturn is rising earlier now and is always a stunning sight. There is plenty of ring detail to be seen at high power on nights of good seeing, as well as subtle banding on the planet's disc. Towards the end of the month it will pass very close to the Beehive cluster, and should be a wonderful photo opportunity. Keep an eye out on the website for an upcoming Saturn observing guide.

There's plenty to eyes on the skies then, whether you're happy to take a quick look or spend some serious time on each object. Provided the clear spells are long enough for the latter of course...

The Main Event.
'Believe it or not’ by Arthur Milnes

Arthur Milnes was the first speaker of 2006. Now people tend to take cover when Arthur is giving a talk, lest they end up as ‘volunteers’ strapped to some strange whirring and flashing gizmo or other, but on this occasion there were no arcane devices or any moving parts involved at all, although Maarten’s computer did struggle a bit to get up and running properly in Arthur’s presence. Proof perhaps that even computers feel fear.

Arthur’s intention was to share with us some of the incredible, amazing and near-unbelievable facts and figures that have come to light during his passionate study of science in general, and astronomy sometimes in particular.

Against the backdrop of a picture of M45, the Pleiades, Arthur told us that on a good clear night we could expect to see about 5000 to 6000 stars. Using binoculars would increase that many times over, and a telescope even more so. The total number of stars in our galaxy is estimated at 150 to 200 billion! Now, when you consider there are billions of galaxies in the universe, just how many stars are there altogether? This is estimated to be 10 to the power of 23! (That’s 10 with 23 zeroes after it, shown on this page as 10^23.) To illustrate this in real terms, Arthur asked us to imagine that each star was a grain of sand. All 10^23 grains of sand are placed in hopper cars in a goods train, and the train then drives past you at a rate of one car per second. For all those grains of sand in the cars to pass you would take…three years! Incredible! And the train would stretch around the Earth 25 times!

There are some rather rapid speeds going on as well. Most people know that the Earth rotates, and that therefore we are moving all the time, but while the Earth rotates it is also orbiting the Sun, and our entire solar system is part of the Milky Way galaxy, which is also moving- it rotates about its centre. It turns out we are actually moving all the time at a speed of about 540,000 mph, or if you prefer- 150 miles per second!

Scaling things down a bit, Arthur put the realm of extremely small measurements under the microscope- the world of micrometers, nanometres and even attometres. The attometre is the smallest unit of measurement, and actually represents 10^-18 metres! He gave an example told by Marcus Chown- if a housefly landed on the surface of a perfectly calm Olympic-sized swimming pool, the surface of the water would rise by one attometre! Conversely, imagine you held something with a size of one attometre on your hand and you wanted to scale it up so that it appeared the same as a 1cm diameter shirt button. If you scaled up the shirt button by the same amount, it would end up with a diameter 8.6 times the size of our solar system!

A very impressive image was shown- one taken by a scanning tunnelling electron microscope, that showed part of a DNA molecule magnified 17 million times. The image showed three twists of the double helix structure, each of which was only 10 nanometres long (1 nanometre = 10^-9 metres). That was impressive enough, but then to be reminded that it was only a very small section of part of a single cell, and that there are a million million cells in our bodies, each single one of which contains copies of 6000 million base pairs from our parents!

The talk was full of fascinating, and frankly mind-blowing facts and figures like these; all illustrated beautifully with a series of pictures displayed on the projector screen, and recounted in Arthur’s easy-going yet informative style.

Science and science fiction writer, Isaac Asimov, inspired the final example Arthur left us with. He suggested that 15 copies of his latest book be placed on a table and numbered 1 to 15. He then issued a challenge to re-arrange those books in every single possible numerical order, at the rate of one ordering per minute. How long do you think it would take?

The answer, believe it or not, was a mind-boggling 2.4 million years! Now that’s something to try with your astronomy magazines…

Next Time.

Next meeting takes place on Tuesday 7th February at the Green House, 7.30pm sharp. The talk, which will be given by Pauline Macrae, is ‘Cassini’, and will be all about the ongoing Cassini-Huygens mission out in Saturn’s neighbourhood. There will also be breakout sessions featuring discussion about the main presentation and an equipment group.

Until the next meeting, Dark Skies to All!

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