by VirtualAstro | Feb 24, 2011
Originally posted on Dark Sky Diary by Steve Owens (@darkskydman)
The BBC news website today has a feature on Double Summertime (DST), the proposal to set all UK clocks forward by one hour throughout the year, so that we might all benefit from longer evenings. The argument is that this will boost tourism, reduce road traffic accidents, and give us more time to enjoy outdoor activities in the evening.
UK amateur astronomers would lose 25% of their dark evening observing hours under Double Summertime
The main argument normally put up against Double Summertime is that there will be an increase in road traffic accidents due to darker mornings. This is technically true, although it is more than offset by the reduction in RTAs as a result of the brighter evenings, and therefore overall it’s safer, saving an estimated 80-100 lives per year. (See section 4.6, pp. 49-50 in the report Road Safety Beyond 2010 for the estimates in detail).
The extra hour of daylight each evening could be worth £3.5 billion through increased tourism, as well as creating around 8000 new jobs.
And finally, the reduced use of lights at night might save an estimated 2% of our daily electricity use, or 1.2 million tonnes of carbon.
So what’s not to like?
Well, not everyone would welcome brighter evenings. It is definitely a minority interest when set against the pro-safety, pro-business, pro-environment arguments above, but the UK amateur astronomy community would be more than a little put out by the change, losing an hour of stargazing each night. Of course, that hour won’t be lost, they’ll simply have to stay up later to observe, but the fact is many won’t. Staying up until midnight on a weeknight when you have got work the next day is very different from staying up till 1am. In addition public star parties will have to start later, therefore attracting fewer people throughout the year. Small concerns maybe, but it’s worth recognising that not everyone in the country would welcome brighter evenings.
| City |
Annual # of hours of darkness*
before midnight under present system |
Annual # of hours of darkness*
before midnight under DST |
% decrease |
| Glasgow |
977 |
731 |
25% |
| London |
1110 |
830 |
25% |
* darkness = after the end of astronomical twilight
As you can see from the table above, amateur astronomers around the country would lose 25% of their dark evening observing hours throughout the year. Of course these “missing” hours could be made up by staying up an hour later, but that’s not always practical.
Just at the point where astronomy is starting to dramatically increase in popularity, with a surge in telescope sales due to projects like the International Year of Astronomy 2009 and BBC Stargazing Live, a switch to DST would put a serious dent in that enthusiasm. The table below is similar to the one above except that it shows the number of hours of darkness before 10pm, the time that an enthusiastic newcomer might stay up doing simple observing, or the latest that a public star party might run. As you can see the % decrease is even more dramatic here, with reductions of more than 1/3.
| City |
Annual # of hours of darkness*
before 10pm under present system |
Annual # of hours of darkness*
before 10pm under DST |
% decrease |
| Glasgow |
515 |
328 |
36% |
| London |
584 |
379 |
35% |
I’m not necessarily arguing against DST, given how many lives it could save, how much money it would bring in through tourism (although the change could seriously hamper an area that is developing its astronomy tourism), and how much it would benefit the
by Steve Owens | Feb 19, 2011
Originally posted on Dark Sky Diary by Steve Owens @darkskyman
Over two weeks between 21 February and 06 March 2011 you can take part in the international project GLOBE at Night, an annual 2-week campaign. During GLOBE at Night, you can record the brightness of your night sky by matching its appearance against the constellation Orion with star maps of progressively fainter stars. Your measurements are submitted on-line and a few weeks later, organizers will release a map of light-pollution levels worldwide. Over the last five GLOBE at Night campaigns, volunteers from over 100 countries have contributed 35,000 measurements.
So what exactly do you need to do? It’s simple, just visit the GLOBE at Night website and follow their instructions. You’ll need to:
1. print out the Orion maps from the activity pack
2. go outside and find Orion. Make sure you wait till it’s properly dark, which is after about 2015 your time. Hint, Orion will be towards the south, and looks like this:
- The constellation of Orion
3. compare what you see with the seven Orion maps, and note down which one it looks like the most. This will tell you the magnitude (brightness) of the dimmest stars you can see
4. report your observation using the GLOBE at Night web app or through their website including the date and time you made the observation, and your latitude and longitude (don’t worry, there’s an interactive map that’ll help you find these).
by Steve Owens | Jan 31, 2011
Originally posted on Dark Sky Diaries by Steve Owens (@darkskyman on Twitter)
The Channel Island of Sark has been recognised for the quality of its night sky by the International Dark-sky Association (IDA), who have designated it the world’s first dark sky island, the latest in a select group of dark sky places around the world.
Sark has no public street lighting, there are no paved roads and cars, so it does not suffer from the effects light pollution in the same way as towns and cities do. This means that the night sky is very dark, with the Milky Way stretching from horizon to horizon, meteors streaking overhead, and thousand of stars on display.
Caption: “Stargazers on Sark enjoy the wonder of the Milky Way”. Image Credit: Martin Morgan-Taylor
The announcement was hailed as a great success by astronomers. Prof Roger Davies, president of the Royal Astronomical Society, said: “This is a great achievement for Sark. People around the world are become increasingly fascinated by astronomy as we discover more about our universe, and the creation of the world’s first dark sky island in the British Isles can only help to increase that appetite. I hope this leads to many more people experiencing the wonders of a truly dark sky”.
The award follows a long process of community consultation, which included the assessment of the sky darkness and an audit of all the external lights on Sark. A comprehensive lighting management plan was created by lighting Jim Patterson of the Institute of Lighting Engineers, and many local residents and businesses have altered their lighting to make them more dark sky friendly, ensuring that as little light as possible spills upwards where it can drown out the starlight.
Caption: “The Milky Way above the Seigneur’s Mill on Sark”. Image Credit: Martin Morgan-Taylor
The government of Sark, the Chief Pleas, were supportive from the start. Conseilleur Paul Williams, chair of the Agriculture Committee, which oversees environmental matters, said: “Sark becoming the world’s first dark sky island is a tremendous feather in our environmental cap, which can only enhance our appeal. Sark is a wonderful island and this recognition will bring our uniqueness and beauty to a wider audience.”
This designation means that Sark joins the select group of international sites chosen for their dark skies, including Galloway Forest Dark Sky Park, which became Europe’s first International Dark Sky Park in November 2009.
Steve Owens, the dark sky development officer who led Sark’s application to the IDA, recognises the benefits that this might have for the community on Sark: “This is an ideal opportunity to bring stargazers to the island throughout the year, and I think that Sark is about to see a boom in astro-tourism, especially in the winter months. We’ve seen a surge of public interest in astronomy in recent years, with the International Year of Astronomy in 2009 and more recently with the success of BBC Stargazing Live, and it’s great that places like Sark and Galloway Forest Dark Sky Park are allowing people from towns and cities to come and experience a dark sky”.
FURTHER INFORMATION
Sark Tourism: http://sark.info/
International Dark-sky association: http://www.darksky.org/
Campaign for Dark Skies: http://www.britastro.org/dark-skies/
by Steve Owens | Jan 27, 2011
Galloway Forest Park’s recreation ranger Lucy Hadley has put together a great podcast from recordings she took during the Geminids Meteorwatch event we ran in the Dark Sky Park on 13 December 2010.
You can listen to it here
On the podcast you’ll hear me, Dr Martin Henrdy from the Astronomy Dept of Glasgow University, and Dr Marek Kukula, public astronomer at the Royal Observatory Greenwich, as we lead the group of meteorwatchers in a tour of the sky. Mainly what you’ll hear though are whoops and squeals of delight as the crowd sees meteor after meteor streaking overhead. A great night!
by VirtualAstro | Jan 10, 2011
Originally posted on Sky and Telescope by by Kelly Beatty, October 6, 2010
Everyone enjoys a great meteor shower, those special times each year when a profusion of shooting stars zip across the sky. So here's a head's up: all of you should circle October 8th on next year's calendar.
This is the yearly date when Earth plows through a tenuous band of space dust created by Comet Giacobini-Zinner along its orbit. Ordinarily, the Draconid shower (formerly called the Giacobinids) puts on a so-so celestial show, delivering about 20 meteors per hour if you can view them under a moonless, pitch-black sky. That's hardly worth staying up for: after all, from a similarly clear, dark site you'll see six or seven random ("sporadic") meteors per hour.
However, this shower has a Jekyll-and-Hyde personality. In 1933 and 1946 the Draconids dazzled skywatchers with astounding meteor "storms" — delivering shooting stars at rates that briefly topped 10,000 per hour! — because Earth crossed through a particularly dense ribbon of debris shed by the comet in 1900. The shower hasn't put on that kind of performance in the years since, though in 2005 it surged unexpectedly to double or triple the usual rate.
If celestial prognosticators are right, we're in for a treat next year, when Draconid rates could top 600 per hour — that's 10 per minute — under ideal viewing conditions. That surge is in the cards because we'll likely clip the stream of particles ejected in 1900. Odds are that it's still largely intact, even though the comet's 6½-year-long orbit periodically puts it in Jupiter's disruptive vicinity.
On October 8, 2011, Earth will pass through several streams of particles ejected over the past 200 years by Comet Giacobini-Zinner.
J. Vaubaillon & others
At a meeting of planetary scientists now under way in Pasadena, California, meteor dynamicist Jérémie Vaubaillon (IMCEE, France) put forth predictions that he'd calculated with colleagues Mikiya Sato and Jun-ichi Watanabe (NAOJ, Japan). If they're right, next October 8th Earth crosses some cometary debris shed by Comet G-Z between 1873 and 1894, peaking at perhaps 60 meteors per hour centered at 17:09 Universal Time, followed at 19:57 UT by a much stronger, 600-per-hour pulse from the 1900 stream.
The rate is very uncertain, Vaubaillon admits, because there's no way to know whether those earlier streams are still densely packed or have been spread thin. Meteor observing wasn't as rigorous back then as it is now. But next year's results should help disentangle which streams are still contributing to the overall rates.
Other meteor specialists are also struggling to come up with firm rates. In 2008 Sato and Watanabe independently estimated a maximum of 500 per hour (at 20:36 UT), whereas NASA researchers Danielle Moser and William Cooke have offered a more optimistic 800 per hour (at 19:11).
These times favor observers in Europe, but don't rush out to book a plane just yet. First, the Draconid shower tends to produce many faint meteors that'll be obliterated by a nearly full Moon that night.
Although Europe is favored for watching the 2011 Draconid meteor shower, this map of average cloud cover during October suggests finding clear skies might prove challenging. (Bluer hues denote more frequent clouds.) Click on the image for a larger view.
Jay Anderson
Second, because the shower's radiant is way up near the head of Draco (declination +54°), the best observing sites would likewise be geographically north. But there's a reason that so few people book vacations to Scandinavia in October: "Weather in Northern Europe is not very pretty," notes Canadian meteorologist Jay Anderson. "October can be very nice, but usually it is the time when the winter cloudiness begins to encroach on the daily weather."
Instead, Anderson's cloud-cover map (at right) suggests that the northernmost "good weather" spot is in the Greek Islands. "Santorini — a favorite place of mine — has clear/few/scattered cloud cover 74% of the time. I know where I'd go."
by Steve Owens | Jan 8, 2011
The Campaign to Protect Rural England (CPRE), in conjunction with the British Astronomical Association‘s Campaign for Dark Skies, has recently announced their 2011 Star Count Project.
Star Count Week 2011 (from CPRE website)
Star Count Week (Monday 31 January – Sunday 06 February 2011) aims to get you outside and looking up, specifically to assess how dark – or light – your sky is.
The technique is simple. 1. Find Orion. 2. Count all the stars you can see within the main rectangle formed by Betelgeuse, Bellatrix, Rigel and Saiph, the four stars that make up Orion’s shoulders and feet. (Don’t count the three bright belt stars). 3. Tell the CPRE.
That’s it. By counting how many you can see, astronomers can calculate your sky’s limiting magnitude, or the brightness of the faintest stars you can see. It’s a very simple – and rewarding – project to take part in.
There are other annual star count programmes, such as GLOBE at Night (March 22 – April 4 2011) which I blogged about during their 2010 event. You can also get more involved and conduct a detailed dark sky survey, or take part in local activities such as the Peak District National Park’s Orion in the Peak project
by Steve Owens | Jan 4, 2011
Originally posted on Dark Sky Diaries by Steve Owens (@darkskyman on Twitter)
With the Quadrantids meteor shower that has just past yielding around 100 meteors per hour in near-perfect New Moon conditions, which showers of the next two years will give us as good a display?
Meteor Shower
There are a few regular, dependable showers that can be relied on to put on a good show year after year, given a good Moon phases, so let’s concentrate on those:
Lyrids 2011
The Lyrids peak this year on April 21/22, only three days after the Full Moon, making conditions far from ideal. The ZHR is around 20, but under bright Moon conditions this will be much reduced, so that from the UK you might only see a few Lyrids per hour.
Persieds 2011
The Perseids peak on 12/13 August 2011 coincides exactly with a Full Moon, making this shower pretty much a write-off in 2011.
Orionids 2011
The Orionids peak occurs on 21/22 October 2011 just after the last quarter Moon, with the Moon rising a little after midnight, just as the meteor shower radiant is gaining height. Again, far from ideal.
Leonids 2011
The Leonids peak on 17/18 November occurs during a last quarter Moon, which unfortunately is smack bang in the direction of Leo, and so will obscure many of the Leonids in 2011
Geminids 2011
The Geminids peak on 13/14 December 2011 will likewise be completely obscured by an almost-full Moon in Gemini.
Quadrantids 2012
The Quadrantids peak on 3/4 January 2012 will feature a waxing gibbous Moon which won’t set until 0400.
Lyrids 2012
The Lyrids peak on 21/22 April 2012 is the first major shower peak in 15 months where the Moon is absent, meaning that you should get good views of this shower which has a ZHR of only around 20.
Persieds 2012
The Perseids peak of 12/13 August 2012 will feature a thin waning crescent moon that’s visible in the sky from midnight, obscuring some of the Perseids.
Orionids 2012
The Orionids peak on 21/22 October 2012 is pretty much Moon-free from around 2330, as the Moon sets.
Leonids 2012
The Leonids peak on 17/18 November 2012 will also be Moon free from early evening, and so presents an opportunity to see a few Leonids.
Geminids 2012
Rounding off this two year run of poor Moon conditions for meteor showers, we end with the Geminids on 13/14 December, coinciding wonderfully with a New Moon on 13 December, meaning conditions will be near perfect.
by VirtualAstro | Jan 3, 2011
Professor Brian Cox and Dara O Briain host three days of live stargazing on BBC 2 featuring epic images from astronomers and observatories from around the globe.
There will be hundreds of free events up and down the country and many useful videos and guides on the Stargazing web page.
Stargazing Live is all about people doing astronomy and witnessing some of the most spectacular astronomical events, including the conjunction of the planets Jupiter and Uranus, the Quadrantid meteor shower and other wonders of the night sky.
In the spirit of getting everyone to look up and share all of the fantastic things going on as well as the BBC 2 program, meteorwatch.org will be doing a twitter meteorwatch for the quadrantids meteor shower, headed up by meteorwatch (@VirtualAstro on Twitter).
As well as all the useful information for beginners on this site and tweets from many people joining in on twitter, meteorwatch.org will have the Meteormap.
Tweet #bbcstargazing or #meteorwatch – first part of your postcode – Country e.g UK – and how many meteors you just saw, e.g 3 to see your meteor results appear on the map.
Your tweet should look like this #bbcstargazing SE1 UK 2 or #meteorwatch PL4 UK 1
Enjoy BBC Stargazing Live, the many events and Twitter Meteorwatch, but most of all, tell your family, tell your friends and tell everyone to look up and enjoy the majesty and wonders of the night sky!
The BBC is not moderating/ overseeing or is responsible for the content on this post, meteorwatch.org or the Twitter Meteorwatch.
