St Helena Online

Tag: Astronomy

Astronomer gives St Helena a gold star

sky with text 640The skies above St Helena have been judged to be dark enough for the island to become one of the world’s most attractive star-gazing destinations.

It could win official recognition as a “dark sky island” within 12 months – though more realistically two years – once work has been done to improve artificial lighting.

A report from astronomer Steve Owens says the island has “very dark skies indeed”.

Click the pic to see a larger image of St Helena's entire night sky, photographed by Steve Owens
Click the pic to see a larger image of St Helena’s entire night sky, photographed by Steve Owens

And he said its connections with famous astronomers could give it an edge over other destinations with less cloud, such as Hawaii, Tenerife and the deserts of Chile and Namibia.

Edmund Halley spent a year on the island making a map of the entire night sky, and remains of his observatory at Halley’s Mount can still be seen.

St Helena’s position near the Equator, and height above sea level, means that nearly every star in both the northern and southern hemispheres can be seen at some point in the year.

Only the middle of oceans and deserts would offer a better view of the stars, Steve Owens told St Helena Online.

The results of his 2012 audit of the island’s night skies emerged just as the Isle of Man announced a 5% increase in tourism income, thanks to star-gazing visitors.

St Helena offers better star-gazing than Sark, the world's first 'dark sky island'. Picture: Peter Capper
St Helena offers better star-gazing than Sark, the world’s first ‘dark sky island’. Picture: Peter Capper

Despite cloudy conditions on his visit in May 2012, Steve found that St Helena’s skies rated  as class two or three on the Bortle scale – that standard measurement.

That gives it a higher rating than Sark, in the Channel Islands, which was the first island in the world to be accredited by the International Dark Sky Association.

St Helena Tourism Association is hoping St Helena can achieve the same recognition – with even higher status. Chairman Vince Thompson organised the trip, with sponsorship from Enterprise St Helena and The Consulate Hotel.

Steve took readings from sites around the island, and left equipment to take further recordings at Broad Bottom – site of the proposed Shelco eco-resort – and the Millennium Forest.

A photograph of the entire sky above the Millennium Forest showed dust bands in the Milky Way, even low on the horizon, and some Zodiacal light – reflections of the sun’s light from dust in the solar system.

Both are rare signs of an exceptionally clear sky.

Steve’s report concludes: “St Helena has very dark skies indeed, ranking as Bortle class two or three in most places outside the major settlements.

“Work is underway to refit much of the island’s street lights, and given that the island is one of the most remote in the world there is no other source of artificial light visible than that generated on the island.

“These figures will only improve given the adoption island-wide of a rigourous lighting management plan, and the award of International Dark Sky Community.”

Vince Thompson said: “The next steps in the process are down to us. Some of the required work is well underway.

“We need to show we have systems in place and work underway or planned to improve night sky conditions.

“The Land Development Control Plan has achieved this, as has work done to reduce the zero upward lighting of certain types of public street lighting.

“Finally, a lighting management plan needs to be formally adopted; this may involve the  assistance of a qualified lighting engineer and therefore some funding from somewhere.”

Steve Owens told St Helena Online that the island had the potential to become one of the darkest places in the world within reach of tourists.

SEE ALSO: There’s gold in them stars

LINK: International Dark Sky Organisation

How Halley mapped the sky from St Helena

A plague commemorates Edmund Halley at the remains of his observatory. Picture by John Grimshaw
A plaque commemorates Edmond Halley at the remains of his observatory. Picture by John Grimshaw

The astronomer Edmond Halley – famous for Halley’s Comet – spent a year on St Helena, creating the world’s first map of the stars over the Southern Hemisphere. JOHN GRIMSHAW tells the story.  

While still a student at Oxford University, Edmund Halley began to observe the heavens with the Astronomer Royal at Greenwich, John Flamsteed, only 10 years his senior, and published papers on sunspots and the solar system.

Influenced by Flamsteed’s project to compile a catalogue of northern stars, Halley proposed to do the same for the stars of the Southern Hemisphere, which had not at that time been observed.

St Helena was chosen being, then, the southern-most territory under British rule. King Charles II sent a letter to The East India Company desiring that Halley be granted free passage to St Helena and, without bothering to take his degree and aged 20, in November 1676, he sailed for Jamestown on the Indiaman Unity.

Halley took with him a great sextant specially constructed of five-and-a-half-foot radius fitted with telescopes in place of sights, his own two-foot quadrant, and several telescopes of different focal lengths up to 24 feet.

The weather in St. Helena proved less good for astronomical observations than Halley had hoped but despite this, by the time he returned home in 1678 he had recorded the celestial positions of 341 stars, which he published in his star catalogue on his return to England, along with a chart of the southern heavens.

On November 7th 1677 he also became the first astronomer to ever observe the complete transit of Mercury across the solar disc, but this came to naught when bad weather in England deprived him of the other half of the observations.

Even though he had left Oxford without a degree he quickly found himself considered among the top astronomers of the day. King Charles II decreed that the University of Oxford must confer a degree on Halley without him having to take the exams.

Later in 1678 he was also elected a member of the Royal Society and at the age of 22 one of its youngest members.

All these honours given to Halley did not sit well with John Flamsteed. Despite his earlier liking of the young college student, soon he considered him to be an enemy.

When, in 1720, he succeeded John Flamsteed as Astronomer Royal, Flamsteed’s widow was so angry that she had all of her late husband’s instruments sold so Halley could not use any of them.

He remained as Astronomer Royal until his death in 1742 at the age of 85, not surviving to see the predicted return of the comet, on 25 December 1758, which would later bear his name.

Halley returned briefly to St. Helena in 1700. Wanting more accurate magnetic charts of the Atlantic Ocean, their Lordships of the British Admiralty lent Halley a small sailing ship, the six-gun, three-masted, 52-foot Paramore, and instructed him to carry out a magnetic survey of the Atlantic Ocean and its bordering lands.

Perhaps considering this task an insufficient justification of the expedition, they also gave him a second one -“to stand soe farr into the South, till you discover the Coast of the Terra Incognita, supposed to lye between Magelan’s Streights and the Cape of Good Hope”.

The Paramore, the first ship built specifically as a research vessel for the Royal Navy, set out in October 1698 on what is regarded as the first sea voyage undertaken for a purely scientific endeavour, but was troubled by both leaks and by a personal conflict between Halley and the naval officer in charge of the ship.

Halley had the man arrested and turned the ship back to England, where a court of inquiry upheld him and gave him sole command of the ship.

The Paramore set out again in September 1699 and by 1 February 1700 the ship had penetrated the Antarctic Convergence to reach below 52 degrees latitude, only 90n miles north of South Georgia.

After this the ship continued to Tristan da Cunha, St Helena, Brazil, Barbados, Bermuda, Newfoundland and finally, at the end of August, back to England.

This article comes from John and Pauline Grimshaw’s collection of excellent St Helena pictures on the internet. See their flickr photostream, with historical notes, here

St Helena and Venus (the planet, not the goddess of love)

It’ll be 105 years before anyone on Earth sees another transit of Venus, when the planet passes in front of the sun. And the one that happened on the night of 5/6 June 2012 was not visible from St Helena. But the island played a significant role in helping astronomers learn about the planet – and much else besides. For a brief history that includes the island’s link with famed astronomers, click here.

SEE ALSO:
There’s gold in them stars

LINK:
“If you can see the mole on Cindy Crawford’s face, you can see Venus” – CBC News

There’s gold in them stars

A dense cluster of stars photographed over St Helena
GOLD STARS ALL ROUND: a section of the night sky over St Helena, photographed by Steve Owens

The way the old saying has it, all that glisters is not gold. But in the case of the stars over St Helena, it seems the saying is wrong.

The astronomer who came to “audit” the island’s night sky in April says he’s giving it a gold rating for star-gazing. That puts it among the clearest skies in the world.

Steve Owens had been invited to the island to see whether it qualified as an International Dark Sky Place, after the accolade was given to Sark, one of the Channel Islands off the northern coast of France.

Vince Thompson describes the visit in his column in the May 4 issue of the re-launched St Helena Independent:

“In Glasgow, where Steve Owens lives, he says he can see about 200 hundred stars from his own garden.  The quality of St Helena’s night sky means 6,000 stars are visible to the naked eye.

“When Steve Owens sailed away from St Helena on 30th April he was able to tell us that the darkness of the St Helena night sky qualifies for ‘Gold Status’.  This means our sky is darker than the Isle of Sark’s which was accredited with ‘Silver Status’.”

The Dark Sky association’s rules require that public lighting meets tight standards to avoid light pollution, which can obscure the view of the galaxies.

Most of St Helena’s lighting was found to meet the rules, and measures to improve the rest are probably sufficient, according to Steve.

St Helena Government recently replaced 60 street lamps with low energy solar-powered lamps.

A statement said: “In addition to reducing the island’s reliance on fossil fuels, the new lights are of a modern design that do not emit light above the horizontal plane.

“This is a requirement for the Dark Skies accreditation, and by replacing 60 non-compliant luminaires with compliant ones we are a step closer to gaining Dark Skies accreditation.

“The guidelines for any additional lighting will be subject to the outcome of the audit being conducted by Steve Owens.”

The statement – issued before the astronomer’s visit – said positive feedback was expected on the work done to date to reduce light pollution.

The sky audit was organised by the St Helena Tourism Association. The main sponsors were Enterprise St Helena and The Consulate Hotel. 

COMMENT:
I’m glad I got the picture I needed; Saint Helena is a very special place indeed, and not just because of its dark skies.

Steve Owens, Scotland
In Search of Darkness

SEE ALSO:
Astronomer snaps night of a million stars (eventually)

LINK:
St Helena Independent

Astronomer snaps night of a thousand stars (eventually)

The night sky appears as a circle in the centre of the image, with the horizon forming the circumference. Details such as headlights are visible as specks.
DARK ENOUGH FOR YOU? St Helena’s night sky: the horizon appears as a circle around the edge

This is a picture of the night sky over St Helena – and it nearly wasn’t taken. Astronomer Steve Owens had travelled from Scotland see whether the island could qualify as an International Dark Sky Place, to encourage star-gazing tourism. But clouds blocked the view. VINCE THOMPSON tells the story.

Steve Owens has completed his audit of the night sky – but his job has been made very difficult due to the ever-present cloud and rain during his week on the island.

Detail of the main image, showing lights and cloud
CLOSING IN: Approaching cloud is visible in Steve Owens’ picture (detail)

He did manage to take some dark-sky measurements earlier in the week, but more were needed and the Thursday night’s attempt to collect more data was totally unsuccessful.

On Friday night he was resolved to stay out all night if needed, to get the photo and extra data that were vital for the audit.

As time started to run out we were working on a Plan B which involved Steve leaving his very expensive camera equipment behind so Stedson George and I could complete the survey. The equipment was to be returned to him by registered post. Desperate situations require desperate measures

Steve’s survey in Friday night could not start until the moon had passed below the horizon, at about 11:20pm. Some time after 10:00pm he checked the sky and saw it was clear. He immediately gathered his equipment and drove out to the Millennium Forest car park to set up his camera and dark sky meter

Steve got there just in time to take a 360-degree photo of a clear night sky. Cloud was starting to form on the horizon.

After that he took some more dark sky meter readings that were needed, and completed his naked-eye observations, which help to indicate how clear the air is between us and the stars

This is great news and we must offer grateful thanks to Steve for being so committed to his tasks.

On Monday, 30 April 2012, he set sail for Cape Town and Scotland – job done

Keep looking up!

SEE ALSO:
A star role for St Helena tourism?

LINK:
In pursuit of darkness: Steve Owens’s Dark Sky Diary

Looking up: a star role for St Helena tourism?

A swirl of stars
Okay... how many people spotted that this was actually taken in the Northern Hemisphere? They're still stars, aren't they? (Picture: Euclid vanderKroew)

Cosmic news: not only have officials been surveying all the land on St Helena, but now an astronomer is on his way to survey the sky.

The stars above Diana’s Peak could become another “national park” in all but name, attracting a new kind of tourist.

That’s if Steve Owens finds that the sky is sufficiently clear for the island to qualify as an International Dark Sky Place.

As Steve says on his star-gazing website, light pollution is a big problem for astronomers living near cities (he lives in the Scottish city of Glasgow). The orange glow obscures all but the brightest stars:

“There are increasingly fewer places where stargazers can enjoy an unspoiled dark sky, but the further you travel from urban areas the more stars you will see, and St Helena as about as far as it’s possible to be from the next town.

“Under such dark skies the Milky Way can be seen stretching from horizon to horizon in an arc overhead, and the heavens are studded with thousands of stars and many nebulae, including the dramatic Magellanic clouds not visible from far northern latitudes.”

Steve has been invited to the island by Vince Thompson – who knows about these things – and the St Helena Tourism Association.

He says: “The St Helena Tourism Association came up with the idea of promoting St Helena as one of the best places in the world to pursue astronomy and general star-gazing, either as a hobby or a profession.

“It could well mean a few more visitors and, in turn, a few more customers for the Association’s members.

“The general idea of promoting astronomy in St Helena has caught on really well with the St Helena Tourism and the St Helena Development Agency, both of whom are contributing to the costs of Steve’s visit.

Steve Owens is going to have a busy eight-day visit, touring schools, giving public talks and workshops as well as seeing the island’s governor and addressing the Legislative Council.”

The expert is travelling in the wake of celebrated astronomers Edmund Halley and Neville Maskelyne, armed not just with a telescope but also with a Sky Quality Meter, to assess the brightness overhead – or lack of it.

The “audit” of the sky is only one step on the path to attracting earth-bound space travellers. New codes on lighting would also be needed if St Helena is to join other remote places in winning Dark Sky status.

Sark, in the Channel Islands – so small it doesn’t even have cars – is one of only 16 International Dark Sky Places around the world.

St Helena has a special attraction – apart from its connections with Halley and Maskelyne, a future Astronomer Royal: “Its location at 16° south of the equator means that virtually every constellation is on display at some time throughout the year,” says the visitor.

Sadly for Steve, he won’t be on the island to observe the rare Transit of Venus, which is what brought the future Astronomer Royal, Maskelyne, to the island. There won’t be another for 100 years.

But he will be arriving in Global Astronomy Month (April).

St Helenians who can’t wait for Steve’s findings to be declared can join in with International Dark Sky Week (14-20 April 2012). Suggestions include throwing a star party, and there’s a website with an online children’s activity book, here.

SEE ALSO:
Eco resort’ moves a step closer in wirebird valley
Do the maths, says economists: tourists equal millions
Relying on tourism poses economic risk, warn territories

LINKS:
In pursuit of darkness: Steve Owens’s Dark Sky Diary
International Dark Sky Association

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