Heart of Darkness - an African Eclipse
By Mike Frost
On Thursday June 21st 2001, the first total eclipse of the new millennium
swept across southern Africa, from Angola to Madagascar. After the disappointments
of 1999 I was determined to see totality again, and so once again I joined
an Explorers Tours expedition to view the eclipse.
The choice of viewing site was a delicate balance of judgment.
Madagascar was a non-starter because of the low altitude of the sun and
the likelihood of cloud. The climate and eclipse duration were best
for Angola, but the continuing civil war there made it far too dangerous.
Likewise, Mozambique was struggling to recover after years of internal
strife, with the result that the infrastructure - hotels and roads - was
poor to non-existent. The southern tip of Malawi barely poked into
the totality zone, so the choice came down to two countries — Zambia or
At first glance the choice seemed to be straightforward. The
eclipse track directly crossed the Zambian capital, Lusaka, and roads eastwards
from the capital ran along the eclipse track. In Zimbabwe, however,
the track of totality ran across the northern part of the country, where
most roads ran north to south, offering little opportunity to change location
if the weather refused to co-operate.
Moreover, Zimbabwe had received unstintingly uncomplimentary press
coverage throughout the previous eighteen months. The increasing
lawlessness of President Robert Mugabe‘s regime, particularly the seizure
of mostly white-owned farms by so-called ”war veterans"of Zimbabwe‘s independence
struggle, and the resultant collapse of the Zimbabwean economy, seemed
to make Zambia the likelier choice.
But first appearances were deceptive. Even allowing for the collapse
of the Zimbabwean economy, Zambia is a much less-developed country,
with poorer and fewer facilities for visitors. And although Zimbabwe
has problems, it does not border the brutal civil war to the north in the
Congo (Zimbabwe does have troops in the Congo, to protect Mugabe‘s diamond
mines and keep the army from causing trouble at home). And the economic
collapse meant that Zimbabwe welcomed tourists as a source of much-needed
In our first few days in Zimbabwe we had ample opportunity to see the
promise of the country. We flew on an Explorers charter flight from
Johannesburg to Victoria Falls. Vic Falls is a superb location, home
to arguably the most impressive set of waterfalls in the world, twice as
wide and twice as high as Niagara. I enjoyed the helicopter flight
and the Zambezi cruise but didn‘t have time for the white water rafting
or the bungee jump. I was particularly impressed by the wonderful
rainbows to be seen in the spray from the falls. Apparently Victoria
Falls is a great place to see Moonbows: but not when it‘s so close to a
From Victoria Falls we spent two days traveling cross-country, first
to Bulawayo and then to the capital Harare. And finally on the 21st,
eleven coach loads of eclipse chasers headed north out of town to intercept
the totality track, which we did just south of Mount Darwin. The
northern part of Zimbabwe is hilly and scrubby, with frequent smallholdings,
tiny mud-hut villages and wooden stockades for cattle. Shortly after
the village of Rushinga, the coaches turned off the metalled road and bumped
down a dusty dirt track. After ten uncomfortable miles, we stopped
just before the bridge over the Ruya River.
Our observing location was in the grounds of Maname school, a collection
of buildings on the slopes heading down to the river. We were welcomed
by the head teacher, Patrick Matiza, carrying his young son; and Patrick‘s
brother, who was sporting a Manchester United away shirt. Explorers Tours
had made a donation to the school in return for access to the school grounds,
and had encouraged us to bring spare biros and books for donation to the
school; a huge pile of gifts rapidly piled up.
The viewing location was very scenic. The Ruya River had a wide
flood plain, but in mid-winter the stream was little more than a brook.
The terrain was sandy and rocky, covered with scrubby brushes and few trees.
The sun was low to the north, above the hills (up to 2500m in height) that
marked the border with Mozambique, 10km to the north. The 470 eclipse
chasers spread themselves along the riverbank. I set up shop immediately
next to the stream. The sky was almost cloudless, with just a few
wisps threatening to spoil the party. Although the Sun was by no
means overhead, it still felt very hot, and the sandy riverbed made for
a suntrap. As we set up our equipment, the children from the school eyed
us with curiosity. Some of them were keen to observe the sun through
filtered telescopes but most seemed to be more interested in the observers
than the eclipse itself. The observers tucked into a buffet lunch
and waited for first contact.
At ten to two the eclipse began. The temperature began to drop
surprisingly quickly, which was a relief given the strength of the sun.
As the edge of the moon crept across the sun the breeze began to rise.
I had used my dinner plate to construct a reflection experiment, filling
it with water in which I hoped to observe the sun, but the breeze rippled
the surface too much for a steady image. My pinhole array (spelling
out HELLO MUM in pinhole suns) was more successful, and a few natural crescent
suns could be seen in the gaps between leaves on the bushes. There
was a large flat bed of rock on my right hand side that I resolved to check
for shadow bands at the end of totality, compos mentis permitting.
By ten to three, the wind had dropped, and I could clearly see the
eclipsed sun reflecting dazzlingly in the dinner plate — the reflected
image was too bright to look at with any magnification. The remaining
clouds had dispersed and conditions were well nigh perfect, with only a
little haze. As the light began to thin we could hear the sound of
crickets, and by the river we noticed sand flies swarming in anticipation
Three o'clock — fifteen minutes to go — and I ran through my checklists,
swapping around lenses (telephoto to main camera, wide-angle to my secondary,
with which I hoped to shoot a panorama during totality). Taping focuses
at infinity, switching to manual exposures on main camera, making sure
my binoculars and second camera were to hand. The accelerating pace
of the darkness nearly caught me by surprise but I was ready by ten past
three, positioning my camera ready for the onset of totality. And
for the next five minutes I watched the sky darken and the Sun‘s crescent
narrow . . .
Thirty seconds to go . . . OK to watch the Sun directly now . .
. the crescent‘s breaking up . . . Bailey‘s Beads — Here
comes the corona!! . . . Yeah!!! . . . Expletives of delight
from my left hand side . . . Off with the lens cap . . .
Check through my viewfinder . . . Sun dead center and looking
gorgeous . . . Run through the exposures one by one . . .
pause between shots to let the camera steady . . . check for
fiery red prominences on the disk . . . lovely one at two o'clock .
. . Quick glance at my watch . . . One minute down!! .
. . Pick up second camera on my left hand side, stand up . .
. begin a series of wide angle panoramic shots from left to
right, sun in the center shot . . . Jupiter outstanding below
and to the left of the Sun . . . One shot looking behind me .
. . life‘s too short to look away from the Sun for long . .
. Gordon on my left has put down my binoculars . . .
Pick them up and study the disk again . . . Fantastic prominence
at three o'clock! . . . uh-oh, two minutes down! . . .
Turn my binoculars away to the left, no sign of Mercury or Saturn, so back
to the Sun . . . group of prominences towards the trailing edge — can‘t be long to go now . . . Time for another run through
the exposures, flicking the camera back in to auto ready for the diamond
ring . . . Here comes the chromosphere!! Pink, pinker,
red . . . And . . . DIAMOND RING!! One shot, two shots,
pause to take it in . . . Here comes the Sun!! WHOOO!! .
. . Cheers and applause . . . Look down to my right . .
. bands of dark and light running away from the Sun across
the flat rock . . . ”SHADOW BANDS ON THE ROCKS!!!" I bellow . . .
people look round . . . YEAHHHHHHHHHHHH!!!!! . . .
I put down the binoculars and paused for breath. ”Well, only eighteen
months to the next eclipse. . ."
The corona was symmetric around the Sun but there was more spikiness
than I had anticipated — my impression was of a corona shaped rather like
a pastry cutter. There was plenty of structure to the corona, streamers
and polar brushes, but as I write I find that I don‘t have a clear memory
of the exact details — perhaps my pictures will jog the memory [they didn‘t],
but definitely something to concentrate on more next time. Likewise,
I didn‘t find too much to remember about my view around the horizon, I
was expecting more variety in the light looking in different directions.
I remember the prominences far better than in my previous (successful)
eclipse, and the long duration of the diamond ring — five seconds plus,
because of a judiciously placed lunar valley — meant that I had time to
enjoy the spectacle AND run off a couple of shots. The shadow bands
were an unexpected bonus — it‘s difficult to contrast them with those I
saw in Curacao, as the surface (rock instead of sand) was different.
All the fascinating phenomena which had so enthralled us up to totality — sharp shadows, crescent pinholes, crickets chirping — were still going
on, of course, but the sheer overwhelming delight of totality made them
seem much less important than just ten minutes before. Nevertheless,
I ran off another couple of exposures of my Hello Mum pinholes, and noticed
to my surprise more bands of light flitting across the cardboard — shadow
bands again? No, sunlight reflecting off the bubbling stream — I took a minute to convince myself this wasn‘t what I had seen immediately
after totality. Then it was time for a beer! Some hardy souls
stayed to the bitter end, to complete their shots of the partial phases
as the Moon gradually withdrew from the scene. I did the rounds of
my fellow observers, checking to see what they had seen. From over
by the school came the sound of singing. The villagers were celebrating
the end of the eclipse with traditional African dancing and chanting.
The children I spoke to seemed curiously unaffected by the eclipse itself — many people had walked away from the viewing site as the partial phase
began, but I‘m not sure if this was to go indoors or because they wanted
to leave us alone. As I left, I noticed an agitated crowd in one
corner of the eclipse site. I strolled across to find out what was
going on and discovered that the remains of the lunch buffet were being
The coaches taking us back to Harare filled up and left one by one.
As we passed each village, the children waved goodbye with frantic excitement.
What did they make of us? Coach after coach of rich westerners driving
past — hundreds of tourists who piled out of their coaches, watched the
skies darken and clear, and then headed off just as quickly as they came.
The next total solar eclipse, on December 4th 2002, starts in Africa, crossing
the southern part of Zimbabwe. But December is the rainy season for southern
Africa, so eclipse chasers will go elsewhere.
Sailing to Philadelphia
by Mike Frost
One of my favourite musical artistes is Mark Knopfler. You will
probably know him as the writer and lead guitarist for Dire Straits, who
had a string of hits (Sultans of Swing, Romeo and Juliet, Private
Investigations, Walk of Life, and others) in the late seventies and early
eighties. In recent years he has recorded a string of idiosyncratic
solo projects and written the scores for a number of movies, among them
The Princess Bride, Cal and, most memorably, Local Hero (from which you‘ll
have heard the main theme ”Coming Home", even if you don‘t know you have!)
I was a great fan of Dire Straits, but some critics made the claim
that, as the band achieved international success, they became transatlantic,
moving away from their roots and writing for an international (but mostly
Certainly early songs such as Tunnel of Love, with its evocative
description of Northumbrian seaside resorts ”from Cullercoats to Whitley
Bay and Rockaway, Rockaway", made way for songs like Money for Nothing,
with its plaintive chant of ”I want my MTV".
But how do you write songs that appeal to fans on both sides of the
Atlantic, without losing sight of your musical roots?
On his latest album ”Sailing to Philadelphia", Mark Knopfler provides
one answer. The title track is a duet with James Taylor, another
veteran of the seventies. The song tells the story of two men, one
a Geordie, one from the West Country, who gave their names to one of the
historic borderlines of the United States.
The men‘s names were Charles Mason and Jeremiah Dixon. And they
* * * * *
On June 8th 2004 (make a note in your diary!) you stand a great chance
of viewing an event that nobody alive has ever seen — namely a transit
of Venus across the face of the Sun. Observers in England are well-placed
to view this event; so, if the weather is good between about 5:20am and
11:15am, you should be able to see Venus as it crosses between the
Earth and the Sun. You‘ll have to project the image, of course, or
use a safe solar filter, but otherwise this rare event should be
straightforward to observe.
Why are transits of Venus so infrequent? Because the orbit of the Earth
around the Sun is slightly inclined to that of Venus; so a straight alignment
is unlikely. Mercury, the only other planet that can pass between
Earth and the Sun, is better aligned, and so transits are rather more frequent
(the last one was in December 1999). Transits of Venus occur in pairs,
8 years apart, separated by an interval of 122 years, which we just now
coming to the end of. There will be transits in 2004 and 2012, but
the last ones were in 1874 and 1882.
The first person who understood planetary motion well enough to be
able to forecast the occurrence of a transit was the great astronomer and
mathematician Johannes Kepler. He correctly predicted the transit
of Venus in 1631 but was unable to have his prediction confirmed as Europe
was on the wrong side of the globe during the transit. Kepler failed
to predict that there would be a second transit 8 years later. The
only person who realised that a transit would take place in 1639
was an Englishman, Jeremiah Horrocks, and he and one his friends were the
only people to view the momentous event.
You‘ll be hearing more about Horrocks (from me, if no-one else) in
the run-up to the 2004 transit.
By the time the next pair of transits came along, in 1761 and 1769,
their observation had become of huge interest to the scientific community.
Observers who view a transit of Venus from two different (widely separated)
locations will see that the planet appears to cross the Sun along two different
paths. This is simply a parallax effect caused by Venus being at
only one third of the distance of the Sun, but it enables astronomers to
calculate a very accurate distance to the Sun, because this can then
be related directly to a measurable distance on Earth. For the first
time, astronomers would be able to estimate an accurate distance to the
Sun, and from that, distance scales for the whole solar system. European
astronomers, principally in England and France, prepared expeditions to
the other side of the world to observe the 1761 transit.
The future Astronomer Royal, Nevil Maskelyne (now of some unjustified
notoriety as the baddie of the Dava Sobel‘s bestseller Longitude) led the
primary expedition to St Helena in the Southern Atlantic Ocean. French
expeditions were planned to Rodrigues in the Indian Ocean, India and Siberia
(we were at war with the French at the time, but our astronomers
were civilized enough to maintain cordial links with their colleagues across
the Channel). As his assistant, Maskelyne chose the assistant to
James Bradley, the then Astronomer Royal, namely Charles Mason.
”He calls me Charlie Mason, a stargazer am I,
It seems that I was born, to chart the evening sky,
They‘d cut me out for baking bread, but I had other dreams instead,
This baker‘s boy from the West Country, would join the Royal Society"
Shortly before the expedition was due to set out, there was a change
of plan. Because of the risk of bad weather in St Helena, it
was decided to launch a second expedition. Maskelyne went to the
South Atlantic, but Mason was dispatched instead to Sumatra in the Indonesian
archipelago. For his assistant he took Jeremiah Dixon, by profession a
surveyor but an amateur astronomer as well.
I am Jeremiah Dixon, I am a Geordie Boy,
A glass of wine with you sir, and the ladies I‘ll enjoy,
All Durham and Northumberland is measured up by my own hand
It was my fate from birth, to make my mark upon the Earth
Mason and Dixon‘s first expedition did not go smoothly. Hours
after their ship, H.M.S. Seahorse, left Portsmouth, it was attacked by
a French warship, ”Le Grand". Eleven men died, thirty-seven were
injured, and the Seahorse was forced back to port. Mason was all
for giving up the expedition there and then, and wrote a letter to the
Royal Society - ”We will not proceed thither, let the Consequence be what
it will". The Royal Society replied that if Mason and Dixon continued
to renege on their agreed expedition, they would be taken to court ”with
the most inflexible resentment" and prosecuted ”with the utmost Severity
of the Law". On February 3rd 1761 H.M.S. Seahorse set sail again.
By early May they had reached Cape Town, where they received news that
their intended observing site in Sumatra had been captured by the French.
This may have been fortuitous for Mason and Dixon, as they were running
out of time to cross the Indian Ocean. They decided to stay at the
Cape, and on June 5th Charles Mason and Jeremiah Dixon were rewarded with
a clear view of the transit. Their observations were priceless, as
the other expeditions to the Southern Hemisphere had much less fortune.
Maskelyne was clouded out in St Helena and the French expeditions suffered
various setbacks, meteorological and political. The authorities took
good note of Mason and Dixon‘s ability to make excellent observations in
* * * * *
A trying piece of litigation had been occupying the British courts for
decades — a dispute between two of the American colonies, Pennsylvania
and Maryland, over their mutual border. In 1632, Maryland had been
granted ”That part of the bay of Delaware which lieth beneath the
fourtieth degree of north latitude". Unfortunately, this description
included the Pennsylvanian city of Philadelphia, which the Pennsylvanian
colonists were not going to give up. The resolution of the dispute
was to shift the borderline to fifteen miles south of Philadelphia, and
measure due west from there.
This was easier in theory than in practice. The Pennsylvania-Maryland
border rapidly ran into mountainous forest, uncultivated by the colonists
and home to the hostile Iroquois Indians. The first attempts to survey
the boundary were made by Thomas Penn, in 1761, but he admitted defeat
after one of the surveying telescopes warped in the rain.
The two colonies asked the government back in England to provide them
with some competent surveyors, and agreed to abide by the results of the
survey. Charles Mason and Jeremiah Dixon were dispatched to do the
In 1763 they began work at Mr Alexander Bryan‘s plantation house, 15
miles due south of Philadelphia. Mason and Dixon worked their way steadily
westwards, clearing the line of the boundary with axes, checking their
latitude by the altitude of stars above the horizon, and placing limestone
border posts (imported from England) every eleven and a half miles.
It was an arduous and dangerous task. After three years, surveying was halted during an Iroquois uprising, and restarted six months later
Surveying finally ceased in 1767, two hundred and thirty three miles
east of Mr Bryan‘s house,and thirty miles east of the present south-west
corner of Pennsylvania. Many of Mason and Dixon‘s original boundary
posts survive to this day, although some have been removed and incorporated
into buildings along the route. The Mason-Dixon line has been re-surveyed
twice subsequently, in 1849 and 1902, and found to be remarkably accurate.
Mason and Dixon stayed in the American colonies for a further year,
making observations of a lunar eclipse and occultations of the moons of
Jupiter, as well as a precise measurement of a meridian in Maryland.
They arrived back in England in November 1768, just in time to be dispatched
on expeditions to observe the next transit of Venus, in June 1769.
Jeremiah Dixon went to Hammerfest Island, north of Norway, and Charles
Mason to Cavan in central Ireland (this transit of Venus was also observed
by Captain Cook from Tahiti in the Pacific Ocean).
On his return from Norway, Dixon reverted to his profession of surveyor,
working in the north-east of England until his death in 1779. Charles
Mason remained a surveyor of the skies, charting the positions of stars
and providing the timings of their occultations by the Moon. This
provided the astronomical solution to the ”Longitude problem" that
so occupied the maritime nations. His work was highly regarded but
Mason felt that the Board of Longitude had not paid him enough for it.
Consequently he sailed again for Philadelphia in 1787, and spent the remaining
ten years of his life there.
* * * * *
Mason and Dixon‘s surveying might have been just a curiosity of local
history, but events were to give it a much greater significance.
Mr Bryan‘s plantation doubtless was worked by slaves, as Maryland was the
northernmost of the agriculturally based states in which slave ownership
was permitted. Pennsylvania, however, was becoming an industrially
based commonwealth, and through the first half of the nineteenth century,
slavery was gradually abolished.
Slaves began to escape northwards to the abolitionist states.
To the west of Pennsylvania, the borderline was formed by the Ohio River,
but increasingly the Mason-Dixon line became a synonym for the boundary
between freedom and slavery. When civil war broke out in 1861, the
miles surveyed by Mason and Dixon became the front line. It‘s no
co-incidence that the turning point of that war, the battle of Gettysburg,
took place only ten miles north of the Mason-Dixon line.
Mason and Dixon could not have known how significant their boundary
would become. To them it was simply a line to survey, but to history
it would mark the boundary between the great fault-lines of nineteenth-century
America — north and south, industrial and agricultural, freedom and
slavery. Mark Knopfler‘s song conveys the sense of adventure
as two astronomers from the old world prepare for their momentous adventure
in the new.
Now hold your head up Mason, see America lies there,
The morning tide has raised the capes of Delaware,
Come up and feel the Sun, a new morning has begun,
Another day will make it clear, why your stars should guide us here
It‘s great song and a good album.
”Sailing to Philadelphia" by Mark Knopfler (Mercury, 542 981-2, 2000)
”Transits, Travels and Tribulations" by J.D.Fernie. American Scientist
The Dictionary of National Biography, entries for Charles Mason and
Jeremiah Dixon (OUP, 1993)
The cartoon, by Harry Dierken, features in an article on the Mason-Dixon
P.S. Yes, I have crossed the Mason-Dixon line during my travels
around Pennsylvania, although I haven‘t seen any of the boundary markers.
Just south of the Mason-Dixon line lies a small town where I had my photo
taken by the town boundary. The sign says ”Welcome to Friendly Frostburg".