MIRA 64
Spring 2003

Editors Bit


An interesting item I came across recently was that scientists who analyse data from the Lunar Laser Ranging Experiment left on the Moon when the Apollo 11 astronauts deployed a reflector array on the planes of the Sea of Tranquillity have reported some watershed results from these long-term experiments, begun over 30 years ago.  A Dr. Jean Dickey, one of a team of investigators from the Jet Propulsion Laboratory said, "Using the Lunar Laser Ranging Experiment, we have been able to improve, by orders of magnitude, measurements of the Moon's rotation. We also have strong evidence that the Moon has a liquid core and laser ranging has allowed us to determine with great accuracy the rate at which the Moon is gradually receding from the Earth."
So even today work is ongoing with respect to finding out evermore accurate results of how our Moon and Earth system works in space.  The first laser ranging retroreflector was positioned on the Moon in July 1969 by Neal and Buzz, the Apollo 11 astronauts.   By beaming laser pulses at the reflector from Earth, scientists have been able to determine the round-trip travel time that gives the distance between the two bodies at any time to an accuracy of about 3 centimetres!  The laser reflector consists of 100 fused silica half-cubes, called corner cubes, mounted in a 46-centimetre square aluminium panel. Each corner cube is 3.8 centimetres in diameter. Corner cubes reflect a beam of light directly back toward the point of origin.

"Lunar ranging involves sending a laser beam through an optical telescope," Dickey said. "The beam enters the telescope where the eye piece would be and the transmitted beam is expanded to become the diameter of the main mirror, then bounced toward the reflector on the Moon."
The reflectors are too small to be seen from Earth, so even when the beam is precisely aligned in the telescope, actually hitting a lunar retroreflector array is technically challenging.
At the Moon's surface the laser beam has spread out to roughly four miles wide, so the task of aiming the beam is like using a rifle to hit a moving penny two miles away.  Once the laser beam hits a reflector, scientists at the ranging observatories use extremely sensitive filtering and amplification equipment to detect the return signal, which is far too weak to be seen with the human eye.  Even under good atmospheric viewing conditions, only one photon is received every few seconds.
From these ranging experiments, scientists know that the average distance between the centres of the Earth and the Moon is 385,000 kilometres with an accuracy of better than one part in 10 billion.  Laser ranging has also made possible a wealth of new information about the dynamics and structure of the Moon.  Among many new observations, scientists now believe that the Moon may harbour a small liquid core.  The theory has been proposed from data on the Moon's rate of rotation and very slight bobbing motions caused by gravitational forces from the Sun and Earth.
Ranging has also determined that the length of an Earth day has distinct small-scale variations of about one thousandth of a second over the course of a year, caused by the atmosphere, tides, and the motions in the Earth's core.  In addition, the precise positions of the laser ranging observatories on Earth are shown to be slowly drifting as the crustal plates on Earth drift, such as the observatory on Maui is seen to be drifting away from the observatory in Texas.
Data also indicate that ocean tides on Earth have a direct influence on the Moon's orbit.  Measurements show that the Moon is receding from Earth at a rate of about 3.8 centimetres per year.   Ranging has also improved our historic knowledge of the Moon's orbit, enough to permit accurate analyses of solar eclipses as far back as 1400 BC.  Continued improvements in range determination and the need for monitoring the details of the Earth's rotation will keep the lunar reflector experiments in service for years to come.

Ivor Clarke, Ed



The End of the Line?

By Mark Edwards FRAS



If like me you read that excellent book "Longitude" by Dava Sobel, about how the problem of determining longitude at sea was solved through John Harrison making a series of clocks that could keep Greenwich time on board a moving ship, you might have thought that all the problems of finding longitude had gone with the passing of the 19th. century.
Especially as in the last chapter of her book "In the Meridian Courtyard" she wrote:
"I am standing on the prime meridian of the world, zero degrees longitude. . . It's paved right into the courtyard of the Old Observatory at Greenwich. . . In 1884, at the International Meridian Conference held in Washington, D.C.. . . They declared the Greenwich meridian the prime meridian of the world. . ."
So that is it, everybody today bases their measurements of longitude on the prime meridian marked by the brass line set in stone at Greenwich. End of story. . .   Well, not quite!
I had the first inkling that the story might not have ended that way was when I read that the Ordnance Survey had traced the origins of the British national grid (OSGB36) back to Greenwich and found that it did not coincide with the line.  However, someone remembered that the line went through the new transit instrument erected by Airy in 1851, whereas when the national grid was first set up Bradley's old transit instrument 19ft. further west was in use.   Once that 19ft. difference was taken into account the grid was found to agree, with a great degree of relief all round.
So that was the first surprise, if you measure the longitude of your observatory from an Ordnance Survey map, you are not referring to the line in Greenwich courtyard at all, but to one about 6 metres to its west!  There were more surprises to come. . .
At the time when Greenwich was declared to be the prime meridian for the world, the observatory also made observations to determine Greenwich Mean Time, on which all other civil times around the world were based. However in these days of atomic clocks, that is no longer the case.   Now the start of the day and the length of the second is determined by international agreement from the average of times kept by all the atomic clocks around the world as regulated by the International Earth Rotation Service (IERS) in Paris.
This leads me to the second reason I had doubts that the brass line in Greenwich was still the prime meridian. Some time ago I read that the day as determined by these atomic clocks started about 300 milliseconds earlier than the old GMT.   This does not sound very much, but it would mean that the day would no longer start on the line at Greenwich, but at a point about 100 metres to the east.
The importance of this new definition for the zero of time and hence the prime meridian is that it forms the basis of the WGS 84 (World Geodetic System 1984) grid used by the Global Positioning System (GPS) satellites. In 1984 this grid was established by international agreement to replace all national grids (which were all based on slightly different prime meridians) to ensure that aircraft passing from one country to another could be correctly identified by their latitude and longitude.
As I posses a GPS receiver, I thought that the next time I was in London I would do an experiment to see if indeed it was the end of the line for Greenwich as the prime meridian.  Setting the GPS receiver to given positions based on the WGS84 grid, I walked into Greenwich Park and up the hill towards the Old Observatory. With mounting excitement I watched the longitude on it gradually count down towards zero. . .   I was at the top of the hill, I was by the courtyard, I could see the line, I was past the line, I was past the courtyard. . .  Hold on, I turned around and walked back to the line.  When I reached the line the GPS read 0 degrees 0 minutes 5.3 seconds West.  There was the proof I needed - it did not read zero!



At this point I wondered what would happen if I changed the GPS receiver to display positions based on the British National Grid. Sure enough, standing on the line it read 0 degrees 0 minutes 0.4 seconds East.  Moving slightly along the observatory building to the west, it read zero near to the line of the old transit instrument.  I could not be sure that it coincided exactly, as with my receiver the GPS position is only accurate to about 10 metres.


The man to the left of the white door is standing on the line.  The old transit instrument is beneath the slot in the roof to the right (west) of the line.
So, if the line is not the prime meridian that most people use, what is?  There was only one way to find out.
Setting off from the line, I walked east away from the observatory building down the path, further into Greenwich Park, while again watching the GPS receiver count down its last seconds of longitude towards the illusive prime meridian of the world. . . 5. . . 4. . . 3. . . 2. . . 1. . . 0!  At this point I hit the. . . LITTER BIN.   No plaque, no polished brass line, nothing to show its great status, just a litter bin!  Yes it is true, the prime meridian of the world is centred on a litter bin in Greenwich Park!




Later I found that I was not the first person to make this remarkable discovery, as questions had been asked about it in the House of Lords.  On 12th. February 1998 Lord Tanlaw asked Her Majesty's Government: "Whether a business or an institution (such as the National Maritime Museum) is liable for prosecution under the Trade Descriptions Act 1968 for selling tickets to the general public purporting to record Greenwich Mean Time on the Prime Meridian, when the time printed is Co-ordinated Universal Time (UTC) on a meridian line 102.5 metres (336 ft) west of the point recognised by the IERS as from 1 January as the official Prime Meridian for the Millennium.
"Whether a householder or business (such as the Millennium Experience) will be liable for prosecution under the Trade Descriptions Act 1968 for publishing promotional material which indicates alignment with the Prime Meridian (0∞ longitude), when the meridian line referred to is not situated along the International Earth Rotation Service (IERS) International Terrestrial Reference Frame (ITRF) which became the official Prime Meridian as from 1 January."
Lord Clinton-Davis replied:
"The Trade Descriptions Act 1968 makes it an offence for a person, in the course of a trade or business, knowingly or recklessly to make false or misleading statements relating to services, accommodation or facilities they provide. It is for authority trading standards departments to decide whether to prosecute under the Act in any given set of circumstances.  I understand that for technical reasons there are several prime meridians, including that which is historically known, and continues to be known as, the Greenwich Meridian — which was adopted at the International Meridian Conference in Washington in 1884. While this meridian is not that currently recognised by the International Earth Rotation Service, it remains the one which is generally known as the Greenwich Meridian. It would, therefore, seem highly improbable that trading standards officers would consider prosecution appropriate in the circumstances described in the noble Lord's Question."
So next time you are in London, ignore the Old Greenwich Observatory and its hordes of tourists, instead take time to visit Greenwich Park and make an offering to the most important litter bin in the world!








The Moon Illusion

By Vaughan Cooper

We have all seen a large Moon rising over the landscape during the autumn, often almost hidden behind trees.  It looks too big, too near, to be real and yet a few hours later. . .  There it is, a normal size Moon riding high and bright in the sky.

Since ancient times it has been noted that the apparent diameter of the rising Moon seems a little larger to the observer than when the Moon is high in the sky.  A strange paradox when you consider that the Moon's angular diameter is actually a little less when it is on the horizon than when on the meridian.
The rising Moon is approximately 239,000 miles away from the observer, but when the rotation of the Earth turns you to a point beneath the Moon, so it is now on the meridian, you will be as much as 4,000 miles (the radius of the Earth) nearer to our satellite than you were when you first saw it rising.  Therefore the rising Moon should appear to us about 2% smaller than when it is crossing the meridian, yet instead of being smaller, the horizon (rising) Moon appears larger, hence the paradox.
Many investigations have been applied to this illusion and modern investigators feel that the answer must lie in the way the body functions, which allows the eye to perceive objects around us.  Experimenters have devised equipment which allows an observers head to be placed, fixed in a frame and follow an image of a rising Moon by moving the eyes only.  By the time the image of the Moon reached an altitude of 35°, the full shrinkage in its apparent size had taken place.  The experiment even allowed the image of the Moon to appear as if below the horizon and slowly rise and the observer noted the size of the Moon seemed to increase until the Moon was on the horizon, i.e. seen straight ahead.
The principal results of the experiments concluded that the size of the perceived Moon is a function of orientation of the eye in their sockets resulting with the horizontal image of the Moon — or the real Moon on the horizon being at their maximum apparent size when seen viewed straight ahead with the eye set squarely in their sockets.  Movements of the head or neck do not seem to be involved in the illusion.
Yet the answer seems far from complete as other factors are involved.  If you see a man 60 feet away an image of a certain size is formed on the retina of your eye.  If the same man now moves to a position of only 30 feet from you, the image becomes twice as big but to your senses the man appears to maintain the same size.  To put it another way, if you see two men of equal height standing 60 and 30 feet from you they do not appear of different sizes.  Thus the brain seems to automatically correct for the distances of familiar objects.  However the brain is not always faithful in its impressions, for example when you are standing 100 feet off the ground in a tall building, look at the vehicles below, from this height the cars appear as toy automobiles, but when on ground level, look again at cars with the same 100 feet distance they will appear of normal size again.  The  same is true of people, from a height they appear as ants whereas from  ground level they appear normal, so why should the brain compensate for distance in one case but not in the other, especially when the objects are familiar to us?
There seems to be no accounting for the action of the brain in this instance for scientists are unaware of how the distance compensating mechanisms of the brain works.
Of one thing the psychologist is sure: memory and past experiences play a large role in impressions and illusions, as further experiments have found, when observer uses one eye and two eyes alternately on the horizon Moon on the same evening the Moon illusion was present.  But when monocular vision was used for an entire evening the illusion failed to occur.  Furthermore people who have lost the use of one eye are not subject to the Moon Illusion.

The above article has been taken from Sky & Telescope, April 1952 by I. M. Levitt, Fels Planetarium

See also MIRA 60, Spring 2002, The Editors Bit









Jeremiah Horrocks -

"A Very Curious Astronomer"

By Mike Frost

All dates prior to 1752 are Julian (old style) calendar.

I may have mentioned this once or twice in recent months, but it's worth repeating again. On June 8th 2004, weather permitting, we will witness an astronomical event that nobody alive has ever seen - a transit of the planet Venus across the face of the Sun. The transit should be visible across Britain, starting at 6.19 BST and finishing at 12.23 BST. With a small telescope, it should be simple to project the solar image onto a screen and follow the progress of the transit (as with all solar observations, it is dangerous to view directly without specialist equipment). If the weather doesn't co-operate, we have another chance to view a transit of Venus on June 5th 2012, but that's the last opportunity during the lifetime of the current readership. The last transit of Venus was in 1882, and the one prior to that 1874. In the current epoch, transits occur in pairs, eight years apart, separated by intervals of 122 years and then 105 years.
The first person to observe a transit of Venus was called Jeremiah Horrocks, and this is his story. I was motivated to research it because it turns out that Jeremiah and I have some things in common. We both grew up in the northwest of England, for example. We're both astronomers. And we were both educated at the same establishment, Emmanuel College Cambridge.
Emmanuel is one of the older colleges in Cambridge University [1]. It's set in some of the loveliest grounds in the university, and features a chapel built by Christopher Wren. Walter Mildmay founded Emmanuel in 1584 to train Puritans for the priesthood. Because of the religious climate, many of the early graduates migrated to America, where they contributed much to the development of the colonies. Pre-eminent amongst the Emmanuel colonists was John Harvard, founder of Harvard University. Other alumni of Emmanuel include Thomas Young, who formulated the wave theory of light; Gowland Hopkins, who discovered vitamins; and more recently, Cecil Parkinson and Griff Rhys Jones.
Not so long ago I sat in the College archive and looked at the admissions register for 1632. Three hundred and forty nine years and five months before me the register was signed
Jeremy Horrox, Lancaster, May 18                2s 6d
The 2s 6d indicates that Horrocks was a sizar — not eligible for a degree until he had paid the full fees of 10s  (Isaac Newton entered Trinity College under similar circumstances). Lancaster indicates the county of birth.
W. Bennet's annotated book of college admissions (1772) adds more detail:
1632. May 18. Horrox, Jeremiah, S, Lancastro: at Toxteth, was a very curious astro.
So who was this "curious astronomer"? We know little about his life; indeed May 18th 1632 is the very first date when we can place him with any certainty. Bennet's book suggests that Jeremiah Horrocks was born in Toxteth, Liverpool, but his family history is a matter of some dispute, and some authors believe that he was actually born in Deane, Bolton, although all agree that he grew up in Toxteth. We know that he was probably born in 1619, making him around 13 years of age on entry to Emmanuel. This was not unusually young for entry to university during the seventeenth century; Lemuel Gulliver, for example, tells us in the opening chapter of Gulliver's Travels that he entered Emmanuel College at the age of 14 [2]. The Cambridge syllabus at the time did not have any scientific content; however it is likely that friends from Cambridge encouraged Horrocks in his leisure pursuits in mathematics and science. In particular, John Worthington, an undergraduate contemporary, probably helped him to establish a network of scientifically inclined friends. Of these, the most important was William Crabtree, a cloth merchant who lived in Salford.
Jeremiah Horrocks left Emmanuel, around 1635, without taking a degree. Again, this was not unusual at the time, as the formal process of applying for a degree was expensive. We can guess that Horrocks intended to complete his degree once he had established a career. It would appear that Horrocks returned to Lancashire, probably to Toxteth, although the next location where we can definitely place him (sending letters to Crabtree in 1639-40) was the village of Much Hoole, a few miles south of Preston.
At the time of the last pair of eclipses, Jeremiah Horrocks was lionised by Victorian biographers, who saw him as an early hero of British astronomy. Perhaps his greatest champion was the Reverend Robert Brickel, vicar of Hoole, and author of  "A Chapter of Romance in Science" in 1874. Brickel maintained that Jeremiah Horrocks had been a previous curate of Hoole church; however, as we'll see, the evidence for this seems to be circumstantial. In 1639, Horrocks was almost certainly too young for a curacy, and perhaps a more likely career was as a tutor or schoolteacher.
It is clear from Horrocks' correspondence that he was following closely the development of "The New Astronomy" which was flourishing in continental Europe, in the capable stewardship of men such as Galileo, Kepler and Hevelius. There was a mass of new astronomical observations available as a result of the invention of the telescope, but just as important was the reduction of these observations to a succinct set of rules of planetary motion. In particular Johannes Kepler had announced, in 1609 and 1619, three groundbreaking laws; for example, Kepler discovered that the orbit of Mars around the Sun was not circular, as had been previously thought, but an ellipse, with the Sun at one focus.
Horrocks embraced these advances with enthusiasm. He made a series of observations of planetary, solar and lunar positions using a small telescope and some home made measuring implements, and analyzed these observations to check their consistency with Kepler's Laws. Horrocks, we believe, was the first person to deduce the shape of the Moon's orbit around the Earth, and find that this too was elliptical, with the Earth at one focus. Whatever the underlying law of planetary motion was, both the Moon and Mars were subject to it.
Horrocks' most famous discovery also resulted from his investigations of Kepler's Laws. Ever since the widespread adoption of Copernicus's solar-based model of the planetary system, it had been known that it was possible for the two innermost planets, Mercury and Venus, to pass between Earth and the Sun. Once Kepler had deduced accurate laws of planetary motion, he was able to make predictions of when these transits might happen. First of all Kepler computed that a transit of the planet Mercury would occur in October 1631. Mercury is the closest planet to the Sun and transits occur much more frequently than Venus (there was a transit of Mars in May 2003 and there will be another in November 2006). Kepler's prediction of a transit was followed up the French astronomer Pierre Gassendi, and he managed to observe it on October 29th 1631. Gassendi wrote, triumphantly, "I have been more fortunate than those hunters after Mercury who have sought the cunning god in the Sun. I found him out, and saw him where no one else had hitherto seen him."
When Kepler turned his attention to Venus, he discovered that there was also a transit due in 1631, on or around November 27th. He also reckoned that this was the only transit visible for another 130 years; on all other passages of Venus through the plane of the Earth's orbit, Venus missed crossing the Sun by a greater or lesser margin. Because of the accuracy of available observations, the exact time of the transit in 1631 could only be predicted to within two days. Gassendi observed on both days but saw nothing, to his frustration. We now know that the transit occurred during the nighttime in Europe, and in the daytime further west. The Emmanuel colonists in America could have viewed the 1631 transit, had they only known to look.
In October 1639, Jeremiah Horrocks set to work reviewing the tables on which Kepler had based his predictions. Horrocks knew that the data contained inaccuracies and inconsistencies; he attempted to reconcile the various tables with his own measurements. Horrocks made a momentous discovery. He realised that the passage of Venus through the Earth-Sun plane in 1639 was not just the "near-miss" that Kepler had predicted — there was a chance that at some time around November 24th, Venus might actually pass between Sun and Earth, giving a second transit.
One can only imagine Horrocks' excitement at this point. Time was very short, and he needed to alert as many astronomers as he could to the upcoming transit. Unfortunately, communications out of West Lancashire were not rapid. Horrocks was able to alert his brother Jonas in Toxteth and his friend William Crabtree in Salford, asking Crabtree to tell another colleague in England. However, there was no time to warn astronomers elsewhere in Europe.
Although Horrocks' predictions were that the transit would occur late on November 24th, he observed throughout the 23rd, just to be on the safe side, and then also on the morning of the 24th. Legend has it that he observed from Carr House (now a private residence), close to Hoole church. By his own account, he set up a telescope in a darkened room so that it projected the solar disk onto a gradated sheet of paper. November 24th 1639 was a Sunday, and according to his account, he was called away in the middle of the day to "greater things, which it was certainly not proper to neglect for these subordinate pursuits". It is this phrase that may explain why Brickel believed that Horrocks was the curate of Hoole.
Business completed, Horrocks was able to return to his telescope at 3.15 pm. His heart must have leapt! "Lo! A most lovely spectacle, the subject of so many aspirations! I saw that a new spot of unusual size, and perfectly circular, had now entirely entered upon the left disc of the Sun, so far that the edges of the Sun and of the spot coincided precisely on the left, forming an angle of contact. Having very little doubt that this was the shadow of Venus, I at once applied myself diligently to observe it."  Horrocks is at pains to point out that the disk was not an ordinary sunspot, which would not be circular. He must, however have been surprised by the size of the disk, which was much smaller than he had expected.
Horrocks was able to observe the Sun for 35 minutes, until the sun set at Hoole. During this time Venus moved part way across the disk of the Sun, and Horrocks made detailed measurements on three occasions. We have no record of any observations by Jonas Horrocks at Toxteth, but we do have William Crabtree's account of the day. At Salford, the weather was cloudy almost throughout the day [plus ca change] but for just a few minutes before sunset, the clouds parted. Crabtree tells us that he sat and stared, awestruck, at the sight, barely believing his eyes, and made no attempt at detailed observation, although he made a brief sketch afterwards, which corroborated Horrocks' measurements.
Victorian artists, unencumbered by any knowledge of the protagonists' actual appearances, let their imaginations run free. In Liverpool museum, in the science gallery, there is a portrait by Eyre Crowe, of Horrocks observing the projected Sun. He is a shadowy figure but clearly portrayed in the puritan garb appropriate to an Emmanuel man. Hoole church has a stained glass window with a more formal portrait of Horrocks, but pride of place goes to Ford Maddox Brown's delightful 1880 mural of Crabtree observing the transit of Venus, adorning a wall of the Great Hall in Manchester town hall (one of twelve memorable events from the history of the city). Crabtree, who was in his twenties, is portrayed as a wild-eyed old man, whilst his young wife, infants in her arms, gazes at him dutifully.
I have some sympathy with the Victorians' romantic view of the day's events. To predict an event which the greatest intellects of the age have overlooked; to have that prediction come true before your very eyes, in circumstances where vagaries of weather and location might have snatched the view from you. To know that you and your friends are the first people ever to see a transit of Venus: and that once the Sun has set that evening, no one else can possibly view the spectacle again for a hundred and twenty two years. It's difficult to imagine the self-control needed to make sober scientific observations in the circumstances — I suspect that most of us would have stared, awestruck, just like William Crabtree. I know I would!
The prediction and observation of the transit was a stroke of immensely good luck for Horrocks, and he made full use of it, setting to work on his magnum opus, "Venus in Sole Visa" (Venus seen upon the Sun). Horrocks realised that he had the perfect example to promote the New Astronomy that he and his friends were so enthusiastic about — he had seen this wondrous sight purely because he had made the effort to check and revise the observations of others, and to use the powerful new theories of planetary motion.
In addition to this triumph for modern science, Horrocks' observation of the transit had revealed some remarkable new facts. Venus was much smaller than the Sun; the disk of the planet was dark, indicating that the planet did not glow by internal illumination but by reflected sunlight. Horrocks also derived a value for the solar parallax (although we now know that his assumptions were flawed), indicating a size for the solar system much bigger than had previously been believed. Using Horrocks' figures we can deduce a distance from the Earth to the Sun of around sixty million miles (still less than the modern accepted value of ninety-two million miles).
Horrocks completed "Venus in Sole Visa" in 1640. Late in 1640, he wrote to Crabtree that he was coming to visit to discuss publication. The visit never took place; Horrocks died, of causes unknown to us, on January 3rd 1641. He was twenty-two years of age. Crabtree (who himself died in 1644) was distraught, writing "I have lost alas, my dear Horrocks. Hinc illae lachrimae [thus the tears fall]. Irreparable loss". W.F. Bushell's 1975 biography of Horrocks nominates him as "The Keats of Astronomy".
Of course, Horrocks' early demise only adds to the romance of his life story - who knows what he might have achieved had he lived to old age. Perhaps the prediction of the transit of Venus would have remained the pinnacle of Horrocks' career, but it is tempting to suppose that he might have applied his capable intellect to consider why the planets moved in their elliptical orbits. The answer to that question, the momentous discovery of the Universal law of Gravity, was finally provided by Isaac Newton, who was born on Christmas Day 1642, within two years of Horrocks' death. It is fascinating to conjecture how much Horrocks and Newton might have achieved had they been able to correspond or to work together. Certainly Newton acknowledged his debt to Horrocks in his own masterpiece, Principia Mathematica.

I hope that the weather favours us on June 8th 2004, as it favoured Horrocks in 1639. Perhaps you will take the opportunity to repeat Horrocks' experiment (projecting the Sun, please, unless you own a safe solar filter). If you do see the transit, spare a thought for the Emmanuel man, the curious astronomer, whose predictions came so spectacularly true, late one November afternoon, three hundred and sixty four years ago.


Notes:

(1)  Emmanuel College Cambridge is a different establishment from Emmanuel College Gateshead, who were in the news recently for teaching "creation science" to their students. The Dean of Emmanuel during my stay was the Reverend Don Cupitt, who spent several books, and a television series (The Sea of Faith), explaining why he didn't really believe in God.

(2)  Yes, I know Lemuel Gulliver is a fictional character — but he still tells us that he studied at Emmanuel! "Gulliver's Travels" was published in 1726, and Gulliver is recounting adventures from his youth; so the date of his arrival at Cambridge would nominally be around 1670. Another fictional resident of Emmanuel was Professor Chronotis, the senior fellow of the college, who in fact turned out to be a retired Timelord. His story featured in the 1979 Dr Who serial, "Shada", from the Tom Baker era. Shada was never shown on TV, as funds ran out before filming was completed, but it is available on video, with Tom Baker narrating the gaps. You can borrow my copy if you're interested.

Primary sources:

From the Emmanuel archives:
College register for 1619, plus notes on other annotations.
Venus in Sole Visa (translation by unknown author).

The author is grateful to Mrs J.M.Morris for assistance with this research.

Secondary sources:

Allan Chapman, "Jeremiah Horrocks, the transit of Venus, and the 'New Astronomy' in early seventeenth-century England" (Quarterly Journal of the RAS, 1990, 31, 333-357)
Michael Maunder and Patrick Moore, "Transit — When Planets Cross the Sun" (Springer-Verlag, 2000)
Peter Macdonald, "The transit of Venus on 2004 June 8" (Journal of the British Astronomical Association, 112,6, 2002)

Pamphlets:

Robert Brickel, "A Chapter of Romance in Science 1639-1874" (Hoole Church, reprinted 1998)
Allan Chapman, "Jeremiah Horrocks and Much Hoole" (Hoole Church, 1994)W.F.Bushell, "Jeremiah Horrocks" (1975, reprinted 1998 by Liverpool AS)








A series of Lunar Observations

by Vaughan Cooper




A series of lunar observations made without optical aid to firstly identify as many of the lunar features as possible and the effects of lunar libration.  The annotated diagrams of the Moon lists the features seen and the degree of shading on my drawings attempts to illustrate which of the Mare are the most conspicuous.  From this I've noticed that Mare Humorum and Nubium are consistently the darkest of the lunar Mare.  Surprisingly I've never heard or seen any reference to this.  Photographs of the Moon I've referred to does not show the subtle effects we can see with the naked eye!
Also I had hoped to see smaller features like Sinus Iridum or possible the larger craters, Clavius, Ptolemaeus or Jenssen, which I had hoped might  be glimpsed as slight indentations along the terminator but at no time was this ever seen, so therefore they are too small to be seen with the naked eye.  In addition to the above I was interested to see the effects of lunar libration, i.e., the slight rotation of the Moon, causing the apparent displacement of the lunar Mare presented to us, towards or away the east/west limbs.  To compare the observation drawings against the annotated diagrams, it will be necessary to rotate the annotated diagram to approximately conform to the observational drawings.  It would be of interest if other members would make similar observations if only to confirm or add to my observations.






Astronomical Pop Quiz 3

By Mike Frost

You may remember astronomical pop/music quizzes one and two, from a few years ago.  Well here's another collection of fiendish questions on (vaguely) astronomically themed songs.  We have ten years of music history to catch up with — Britpop, Britney, the Spice Girls, Will and Gareth, Eminem, Tatu - but they don't all feature in this quiz!  Plus a whole series of really obscure lyrics and song titles which friends and colleagues have dredged up from the lower reaches of their consciousness.     Good luck!

Answers in the next MIRA

Round 1 — Song Titles
Who had a single called? :-

1.   Walking on the Milky Way     #17, 1996
2.   Walkin' on the Sun              #19, 1997
3.   Cosmic Girl                         #6, 1996
4.   Spacer                               #18, 1979
5.   Saturn 5                            #20, 1994
6.   Spaceman                          #1, 1996
7.   Lucky Star                         #14, 1984
8.   Lucky Stars                        #3, 1978
9.   Girl from Mars                    #11, 1995
10. Drops of Jupiter                  #10, 2001
11. Ticket to the Moon              #24, 1982
12. The Whole of the Moon        #26, 1985 & #3, 1991
13. Everyone's Gone to the Moon  #4, 1965


Round 2 - Lyrics
These range from easy (ish) to impossible. Name the artist and the song in which the following lines appear:

1. "And you flew your Lear Jet to Newfoundland
    To see the total eclipse of the Sun. . ."
Hint - Female artiste, top 3, 1972

2. "The way you look to a distant constellation,
    That's dying in a corner of the sky,
    These are the days of miracle and wonders,
    And don't cry, baby don't cry. . ."
Hint — Singers of lyrics 1 and 2 have the same surname

3. "Shooting stars across the sky,
    Pure and simple every time"
Hint - Band with a football connection, 1993

4. "Jupiter and Saturn,
    Oberon, Miranda and Titania,
    Neptune, Titan, stars can frighten. . ."
Hint - From the first album of a famous group, 1967

5. "I spy in the night sky don't I
    Phoebe, Io, Elara, Leda, Callisto, Sinope
    Janus, Dione, Portia, So many moons. . ."
Hint - Album track by a popular band, 1994

6. " 'Cos men are from Venus and girls are from
    Mars"
Hint - Better known in a group

7. "No Libra Sun, no Halloween. . ."
Hint - Big selling single, 1984

8. "The Human Race has walked the Earth for two point seven million,
    and we estimate the Universe at thirteen,
    fourteen billion.
    When all these numbers tumble into your imagination,
    consider that the Lord was there before creation."
Hint - Already featured in this quiz


Round 3 — What comes next?
A bit like round 2, except that the title of the song comes next.  Song and artist please!

1. "We've got stars directing our fate, and we're praying it's not too late. . ."

2. "Each night I ask the stars up above"

3. "Walking in the moonlight, love making in the park. . ."


Round 4 — Miscellaneous:

1.  Jason Spaceman runs which band?  What's his real name, and where does he come from?

Who had an album called?
2.  Mercury Rising
3.  Meteora

And who had album tracks called: -

4.  Across the Universe
5.  St Judy's Comet
6.  Set the Controls for the Heart of the Sun.
7.  Hey Mr Spaceman
8.  Fly me to the Moon
9.  Champagne Supernova