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AstroEvents- Hunting things that “Flash” in the January Sky

Credit: David Dickinsen

2012 is here, and the world shows no sign of ending as the heavens spin on their appointed rounds high overhead. But the diligent observer may be rewarded with several unique an spurious sights, both natural and manmade…

1st up is everyone’s favorite meteor shower named after an obsolete constellation; the Quadrantids peak the morning of January 4th in what is the first large meteor shower of the year. The peak is very swift, only lasting about 12 hours or so and is centered this year on 2:00 AM EST/7:00 AM UTC. This favors the U.S. East Coast in 2012, as the 79% waxing gibbous Moon will set around 2AM local the morning of the 4th for observers in mid-northern latitudes. The radiant of the shower lies at a declination of 52° degrees north at the junction of the modern constellations of Draco, Bootes and Hercules, and thus activity may be visible pre-midnite local, although the setting of the Moon and the rising of the radiant will raise sighting prospects considerably. Expect swift-moving meteors headed outward from the radiant above the handle of the Big Dipper to appear anywhere in the sky. The Quadrantids have been known since the early 1800’s, but there has been much conjecture as to the source parent body. Astronomer Fred Whipple noted in 1963 that the stream bears some resemblance to the Delta Aquarids, and that the orbital path has undergone alterations by the planet Jupiter in the last few thousand years. In 2003, SETI researcher Peter Jenniskens proposed that the source may be then recently discovered asteroid 2003 EH1, which has been tentatively linked to Comet C/1490 Y1, which approached Earth at a distance of 0.52 Astronomical Units on January 12th 1491. Be sure to keep an eye out for Quadrantids on these chilly January mornings, as we commemorate Quadrans Muralis, a constellation that is no longer! (more…)

The World’s Unluckiest Stargazer! – Fingers Crossed For The Perseids?

I am the dead albatross on your boat.

I am the peacock feather in the house.

I am horseshoe carelessly nailed upside down so all the good luck falls out down a grid.

If you ever see me coming to stand next to you at a star party, meteor shower, or eclipse, you have permission to make the cross sign with your fingers and run backwards as fast as you can.

That’s because, for my 33 and a half years of sky gazing, I have managed to cause cloudy skies and inclement weather at every single major event I have attended.

Just for the record, I’m a keen amateur astronomer without a telescope. I follow as many Twitter astro accounts as I can, avidly retweeting the latest data from Cassini, and following lonely Mars landers as they bump across rusty rocks. I cried the first time I saw the ISS, and as a child, I used to stand in the garden with a compass, straining hard to see the northern lights. I never did.

My bad luck began in earnest when I went to Cornwall for the eclipse. A boyfriend and I spent a small fortune hiring out a dank, uncomfortable cottage in the middle of nowhere. I was so excited that I woke up at 6.30am every morning, causing us to be grey faced and exhausted for the whole pitiful ‘holiday.’ And of course, on the big day, there was 100% cloud cover and it was so cold we had to wear gloves.

One night, me and the chap were out in Sefton Park, Liverpool, admiring a wonderful conjunction of several planets dancing around a new moon like fairy lights. Flushed with happiness, we went in and congratulated ourselves for figuring out how to use a planisphere.  Next morning we were mortified to find out aurora had been visible ten minutes after we went in.

And indeed, only last week, I was photographing some incredible clouds where I live in Bristol, only to be told a short while later that even more aurora had decided to shimmy their way on to the sky’s stage while I had my back turned.

I travelled to America last year, and on my first night, I was so jetlagged that I shut the blind to keep out an incredibly bright moon. Mr Moon was very cross at my ignorance, and proceeded to turn bright red with rage, causing me to miss a spectacular lunar eclipse.

But the thing I have had the LEAST luck with…is meteor showers. I have stood out in back gardens and dark fields trying to catch a glimpse of these fleeting sky streaks at least three times a year from the age of 15. And guess what? Except for ONE Leonid I saw, cutting through soupy orange cloud two years ago, I have not had ANY luck. Truly disheartening.

That is, if you forget about last year. I was in Portland, on the west coast of America. Through a set of remarkable coincidences, which really do make me wonder if we are being pulled through our lives by twinkling cosmic threads, I ended up meeting some wonderful people who shared my love of all things that require tipping your chin up to 90 degrees to observe.

They took me out to a pitch-black nature reserve, bundled up with blankets and deckchairs, as bullfrogs boomed in the blackness, and baby racoons cavorted in the undergrowth.

On that magical, starry, starry night, we counted several hundred Perseids, each one causing me to gasp and grip the arm of my chair. One of the most memorable experiences of my life and one I long to repeat.

So. Will I be turning my head skywards for the Perseids this year? Of course I will. But judging from past form, I’d say, chances are, Bristol is not going to enjoy clear skies. I just seem to have that unfortunate effect on the sky over my head.

So if there are any astronomers in the Bristol area hoping for a good viewing, you may want to drive me out of town with planks and pitchforks. Either that, or take a trip to Inverness.

Follow me for further antics on twitter, I am @RadioVicky

The Lowest Full Moon of the Year

Originally posted on Dark Sky Diary by Steve Owens (@darkskyman on twitter)

Tonight (actually around 0130 tomorrow morning) the Full Moon will reach its highest point due south, just an hour and a half after the eclipse ends. Despite being at its highest in the sky, you’ll still struggle to see it, as it is very low down. In fact the Full Moon nearest the Summer Solstice is the lowest Full Moon of the Year

First, let’s begin with the definition of “Full Moon”. A Full Moon occurs when the Moon is diametrically opposite the Sun, as seen from the Earth. In this configuration, the entire lit hemisphere of the Moon’s surface is visible from Earth, which is what makes it “Full”. There is an actual instant of the exactly Full Moon, that is the exact instant that the Moon is directly opposite the Sun. Therefore when you see timings listed for the Full Moon they will usually include the exact time (hh:mm) that the Moon is 180° round from the Sun (we call this point opposition). Here’s a list of the times of all Full Moons between June 2011 and June 2012:

Month Date of Full Moon Time of Full Moon (UT)
June 2011 15 June 2014*
July 2011 15 July 0640*
August 2011 13 August 1857*
September 2011 12 September 0927*
October 2011 12 October 0206*
November 2011 10 November 2016
December 2011 10 December 1436
January 2012 09 January 0730
February 2012 07 February 2154
March 2012 08 March 0939
April 2012 06 April 1919*
May 2012 06 May 0335*
June 2012 04 June 1112*

* UK observers should add on one hour for BST As you can see from this table, the instant of the Full Moon can occur at any time of day, even in the daytime when the Moon is below the horizon. So most often when we see a “Full Moon” in the sky it is not exactly full, it is a little bit less than full, being a few hours ahead or behind the instant of the Full Moon. I’ll refer to this with “” marks, to distinguish this from the instant of the Full Moon (they look virtually identical in the sky). The Moon rises and sets, like the Sun does, rising towards the east and setting towards the west, reaching its highest point due south around midnight (although not exactly at midnight, just like the Sun does not usually reach its highest point exactly at noon). And like with the Sun the maximum distance above the horizon of the “Full Moon” varies over the year. The Sun is at its highest due south around noon on the Summer Solstice (20 or 21 June) and at its lowest due south around noon on the Winter Solstice (21 or 22 Dec) (of course the Sun is often lower than this, as it rises and sets, but we’re talking here about the lowest high point at mid-day, i.e. the day of the year in which, when the Sun is at its highest point that day, that height is lowest…) And because Full Moons occur when the Moon is directly opposite the Sun, you can imagine the Moon and Sun as sitting on either sides of a celestial see-saw: on the day when the Sun is highest in the middle of the day (in Summer), the Moon is at its lowest high point at midnight; and on the day when the Sun is at its lowest high point in the middle of the day (in Winter), the Moon is at its highest high point at midnight. This means, in practical terms, that Summer “Full Moons” are always very low on the horizon, while Winter “Full Moons” can be very high overhead. Here’s a table of the altitude of the “Full Moon” when due south. Remember the times in this table don’t match the exact time of the Full Moon, but instead have been chosen as the closest in time to that instant, and so have be labelled “Full Moon” (in quotes).

Month Date of Full Moon Time of Full Moon (UT) Time/Date of “Full Moon” due S Time from/since instant of Full Moon Altitude due S (degrees)**
June 2011 15 June 2014* 0127BST 16 June 2011 +4h13m 10° 05′
July 2011 15 July 0640* 0012BST 15 July 2011 -7h28m 10° 24′
August 2011 13 August 1857* 0126BST 14 August 2011 +5h27m 19° 19′
September 2011 12 September 0927* 0049BST 12 September 2011 -9h38m 31° 49′
October 2011 12 October 0206* 0053BST 12 October 2011 -1h13m 44° 16′
November 2011 10 November 2016 0005GMT 11 November 2011 -3h49m 53° 24′
December 2011 10 December 1436 0030GMT 11 December 2011 +9h54m 56° 03′
January 2012 09 January 0730 0006GMT 09 January 2012 -7h24m 53° 36′
February 2012 07 February 2154 0031GMT 08 February 2012 +2h37m 43° 47′
March 2012 08 March 0939 0000GMT 08 March 2012 -9h39m 35° 37′
April 2012 06 April 1919* 0145BST 07 April 2012 +5h26m 21° 45′
May 2012 06 May 0335* 0102BST 06 May 2012 -3h33m 15° 20′
June 2012 04 June 1112* 0047BST 04 June 2012 -11h25m 11° 49′

* UK observers should add on one hour for BST ** The altitude here is based on my observing location in Glasgow, Scotland. You can find out how to work out how high these altitudes are here. As you can see from this table, the highest “Full Moon” due S this year occurs at 0030 on 11 December 2011, when the Moon will be over 56° above the southern horizon (approximately the height of the midsummer mid-day Sun which culminates at 57°34′). Compare this to the “Full Moon” this month, just after the eclipse, in the morning of 16 June, when the Moon barely grazes 10° above the horizon, and you can see just how low the midsummer Full Moon can be. In fact the closeness of summer “Full Moons” to the horizon means that this is an ideal time of year to try and observe the Moon Illusion.  

The Equation of Time

Originally posted on Dark Sky Diary by Steve Owens (@darkskyman on twitter)

Today, 13 June, is one of only four days in the year when the time as read on a sundial will be exactly correct.

Sundials usually tell the time using the shadow of the gnomon as cast by the Sun. This is possible as the Sun appears to move across the sky at an approximately constant speed, and so the shadow of the gnomon also moves at an approximately constant speed. The inconstancy of the Sun’s apparent motion in the sky – and therefore of the gnomon’s shadow on a sundial – is the subject of this article, and is calculated using the Equation of Time.

If you look at the shadow of a sundial’s gnomon it will fall onto a curve of numbers, along hour lines indicating local solar time. This is not equal to the official clock time until three important corrections are made:

Please read the rest of this article on Dark Sky Diary

Total Lunar Eclipse 15 June 2011

Originally posted on Dark Sky Diary by Steve Owens (@darkskyman on twitter)

The first total eclipse of the Moon of 2011 occurs this Wednesday evening, 15 June 2011, and it will be the longest lunar eclipse in over a decade. However the views from the UK (and Europe) will be constrained by the fact that the Moon will be below the horizon for much of the eclipse, and will rise fully eclipsed, or in some cases even coming out of eclipse. It’s still worth having a look though: just try to find somewhere with a very low and clear SE horizon, as this will be the direction in which the Moon will rise, and it will be in eclipse only while it is VERY low (only a few degrees above the horizon).

A lunar eclipse occurs when the Moon, in its orbit around the Earth, passes into the Earth’s shadow, as cast by the Sun. You might imagine that this would happen once every lunar orbit, or once a month. That it does not is due to the fact that the Moon’s orbit around the Earth is tilted by around 5 degrees compared with the Earth’s orbit around the Sun. So in most orbits the Moon passes above or below the Earth’s shadow.

Please read the rest of this article on Dark Sky Diary

Sark: The World’s First Dark Sky Island

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/

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