It never fails to amaze me whenever one of our great observatories manages to capture the beauty that fills our night skies. Here is one of those picture postcards…. “This intriguing new image from ESO’s Very Large Telescope shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star located about 3300 light-years away in the constellation of Scutum (The Shield). This is the most detailed picture of this object ever taken.
Stars the size of the Sun end their lives as tiny and faint white dwarf stars. But as they make the final transition into retirement their atmospheres are blown away into space. For a few tens of thousands of years they are surrounded by the spectacular and colourful glowing clouds of ionised gas known as planetary nebulae.
This new image from the VLT shows the planetary nebula IC 1295, which lies in the constellation of Scutum (The Shield). It has the unusual feature of being surrounded by multiple shells that make it resemble a micro-organism seen under a microscope, with many layers corresponding to the membranes of a cell.
These bubbles are made out of gas that used to be the star’s atmosphere. This gas has been expelled by unstable fusion reactions in the star’s core that generated sudden releases of energy, like huge thermonuclear belches. The gas is bathed in strong ultraviolet radiation from the aging star, which makes the gas glow. Different chemical elements glow with different colours and the ghostly green shade that is prominent in IC 1295 comes from ionised oxygen.
At the centre of the image, you can see the burnt-out remnant of the star’s core as a bright blue-white spot at the heart of the nebula. The central star will become a very faint white dwarf and slowly cool down over many billions of years.
Stars with masses like the Sun and up to eight times that of the Sun, will form planetary nebulae as they enter the final phase of their existence. The Sun is 4.6 billion years old and it will likely live another four billion years.
Despite the name, planetary nebulae have nothing to do with planets. This descriptive term was applied to some early discoveries because of the visual similarity of these unusual objects to the outer planets Uranus and Neptune, when viewed through early telescopes, and it has been catchy enough to survive . These objects were shown to be glowing gas by early spectroscopic observations in the nineteenth century.
This image was captured by ESO’s Very Large Telescope, located on Cerro Paranal in the Atacama Desert of northern Chile, using the FORS instrument (FOcal Reducer Spectrograph). Exposures taken through three different filters that passed blue light (coloured blue), visible light (coloured green), and red light (coloured red) have been combined to make this picture.”
- adapted from a ESO press release.
Tags: IC 1295, planetary nebula, Scutum
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GLOBE at Night is a worldwide, hands-on science and education program to encourage citizen-scientists worldwide to record the brightness of their night sky. During five select sets of dates in 2013, children and adults match the appearance of a constellation (Orion or Leo in the northern hemisphere, and Orion and Crux in the southern hemisphere) with seven star charts of progressively fainter stars (www.globeatnight.org/observe_magnitude_orion.html).
Participants then submit their choice of star chart at www.globeatnight.org/webapp/ with their date, time and location. This can be done by computer (after the measurement) or by smart phone or pad (during the measurement). From these data an interactive map of all worldwide observations is created (www.globeatnight.org/map/). Over the past 7 years of 10-day campaigns, people in 115 countries have contributed over 83,000 measurements, making GLOBE at Night the most popular, light pollution citizen-science campaign to date (www.globeatnight.org/analyze.html).
The GLOBE at Night website is easy to use, comprehensive, and holds an abundance of background information (www.globeatnight.org/learn.html and www.globeatnight.org/observe.html). Guides, activities, one-page flyers and postcards advertising the campaign are available at www.globeatnight.org/pdf/.
Through GLOBE at Night, students, teachers, parents and community members are amassing a data set from which they can explore the nature of light pollution locally and across the globe. The remaining GLOBE at Night campaigns in 2013 are: March 3 – 12, March 31 – April 9, and April 29 – May 8.
Make a difference and join the GLOBE at Night campaign.
- a message from NOAO
Tags: Globe at Night
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Latest episode of Night Sky is now online and this week I give skywatchers the basics on how to track down one of the most distant objects the unaided human eye can see in the night sky. The Great Andromeda galaxy, also known as Messier 31, sits nearly 2.6 million light years away and is actually a fairly easy target to hunt down from dark skies but also from suburban locales when using binoculars. Autumn is the best time of the year to try your hand at finding Andromeda galaxy as it rises in the east in the evenings this time of the year.
Tags: Andromeda galaxy, m31
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Located some 550 light years away in the northern constellation Cancer, the Beehive cluster is home to 1000 young stars born about 600 million years ago. It is a popular binocular target for skywatchers during winter and spring and can even be glimpsed with the naked eye from a dark location.
The new planets, dubbed Pr0201-b and Pr0211-b, are both “hot Jupiters”—gas giants that orbit extremely close to their parent stars, and while there’s little chance for life on these worlds, they are offering tantalizing new directions for planet hunters to follow…
Tags: Beehive cluster
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For skywatchers August will be a busy month with a meteor shower and multiple planetary close encounters!
For early bird skywatchers the goddess of love, Venus dominates the dawn skies in the east perched firmly in the constellation of Gemini, the twins. The great white beacon rises nearly 3 and half hours before the sun every morning and through a small telescope appears like a miniature version of a quarter moon.
Look below Venus for its fainter companion Jupiter – the largest planet in the solar system – sits below nestled between the horns of Taurus the bull constellation. On August 11th the moon will form a celestial triangle with the jovian giant and the eye of the bull – the star Aldebaran. Two mdays later a razor thin crescent moon will park itself to the upper right of Venus.
Watch these two worlds closely and you will notice that while they have been hanging around each other for the past couple of months, the much speedier Venus will quickly increase the gap with Jupiter so that by the end of the month there will be 40 degrees apart.
On August 13 for those with telescopes, Venus will do a disappearing act as it slips behind the very upper portion of the crescent Moon during the daytime. Known as an occultation, this dramatic event however will be a real challenge to catch because it will be occurring in the late afternoon while luna sinks quickly in the low western horizon sky. The first hint of Venus creeping behind the moon will begin at 4:36pm and will take about 25 seconds to completely disappear. Since the moon will be only a few degrees in altitude (eastern N. America) your best bet to catch this event is to find a location that has a clear line of sight right down to the western horizon – like highway overpasses, hilltops and lakesides. Check out a listing of occulation times here.
But there is even more cosmic action in the evening skies. Look towards the west at nightfall for an impressive stellar grouping of the planets Mars, Saturn and the star Spica, in the constellation Virgo. Take note of the diverse colours of these three objects, with orange-hued Mars, yellowish Saturn and brilliant blue-white Spica. The most eye-catching aspect of this stellar trio will be watching them play musical chairs in the sky as they shift positions over the course of the month as they move along in their respective orbits around the Sun.
Then at dusk on August 21th the three objects form an equatorial triangle with the waxing crescent Moon just below.
Shooting Stars Galore
The big astronomical crowd pleaser this month however has to be the famous Perseid meteor shower. Peaking on the night of August 11th and into the early morning hours of August 12th, conditions promise to be good this year because there will only be a crescent moon rising after 1 am so minimal interference from its light is expected. You can expect up to 20 to 30 meteors per hour visible from suburbs and up to 60 from a dark sky.
You can expect about half that many the night before (Aug.10) and after (Aug.13). Best way to see the shower is to lie back on the ground or on reclining lawn chair facing the northeast sky with your naked-eyes. Most of these meteors are the size of a grain of sand and are travelling at about 150,000 km per hour, burning up at about 100 km above your head.
The Perseids get their name from the constellation Perseus – where the shooting stars seem to radiate from in the sky. The meteor shower originates from a cloud of particles in space that was shed by a comet that orbits the Sun. Every year at the same time of year, Earth slams into this cloud of debris, creating a cosmic shower in the heavens above.
BTW if the skies are clear and you are in Montreal area on August 11th, join me and the Royal Astronomical Society of Canada for a free Perseids star party at the Morgan Arboretum in Ste. Anne De Bellevue starting at 8pm with a lecture- rain/cloudy date is August 12th.
Tags: Mars, Saturn, Venus
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More than 30,000 light years from Earth lying at the core of our home galaxy, the Milky Way, are weird clumps of warm, dense gas that may represent seeds that will grow into monster black holes one day, according to a new study.
A team of Japanese astronomers announced this bizarre finding this week using powerful radio telescopes. Their observations show that three of these masses are growing in size, thanks to supernovae explosions estimated to have occurred 60,000 years ago. What is even stranger is that the team calculated the power of that ancient eruption as being equivalent to 200 individual supernovae going off simultaneously! Since no single star could cause such an epic blast, researchers believe that a massive star cluster – equivalent to 100,000 times the mass of the sun – lies hidden behind the veil of one of these masses and is the source of the power.
While backyard astronomers don’t have the technology to see these exotic objects, they can find its general location in the night sky. Face the south sky on any late summer night and look toward the horizon for the constellation Sagittarius. look for a bright asterism – or star pattern – in the shape of a giant teapot – that marks the main section of the constellation. This also marks the general direction of the centre of the Milky Way – 30 thousand light years away!
Read more about this discovery here
Tags: Black holes, Sagittarius
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Look towards the low eastern horizon at least 30 minutes before your local sunrise Wednesday (July 4) you get a chance to see planet Venus – brightest celestial object in the middle of the 250 light year distant Hyades cluster – the head of Taurus the bull. Meanwhile 65 light year Aldebaran and- the ye of the bull is below and jupiter is above Venus.
Tags: Taurus, Venus
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With the shortest nights of the year there is not too many hours left for stargazing however they are totally packed with beautiful celestial events.
Look up after 10 pm any night in July and you’ll easily find the famous Summer Triangle pattern formed by the bright stars Deneb, Altair and Vega riding low in the southeastern sky while the iconic Big Dipper dominates the high northwest sky. Both of these star patterns are not constellations but called asterisms – sort of a cosmic ‘connect the dots’ in the sky which the human eye and mind makes out easily. The Summer Triangle is actually three individual, classic constellations – Vega is with Lyra, Deneb is the brightest in Cygnus, while Altair is the lead in Aquila. Meanwhile the Big Dipper is actually the rump of the Great Bear – Ursa Major. While it might be hard to make out what exactly ancient astronomers were seeing in the sky with constellations, basically knowing these two asterisms is a great start in learning your way around the night sky.
But there is a true constellation visible throughout summer that kind does look like its mythical figure it’s supposed too. Face the south around 10 pm on a clear night and the S-shaped constellation Scorpius stretches up from the horizon. Pinning down the scorpion in the sky is its heart, represented by the bright orange star Antares. A red supergiant with a diameter about 830 times larger than our Sun, Antares shines 60,000 times brighter and is a distant 553 light-years away.
Not sure how to find Antares? On July 28 the Moon will be parked just above the bright star, making for a convenient guidepost.
If you have binoculars or telescope, its worth scanning this part of the sky – and even from light polluted suburbs you can see the region is chock full of clusters and clouds of stars. That’s because Scorpius lies near the same direction as the Milky Way core – making it one of the best panoramic stargazing tours of the summer.While most stars we see at night are relatively nearby ie. within a couple thousand light years from Earth, when looking at the hazy Milky Way towards Scorpius – we are looking at the light from clouds of millions of stars over 20,000 light years distant. Pretty cool eh?
Meanwhile if we look at planets now, the first two weeks of the month sees the closest world to the Sun and most challenging to observe, Mercury, quickly sink in the western sky after sunset. We’ll have to wait for the best views until August when it moves to the other side of the Sun and makes an appearance as a morning star.
Two other planets however remain easy targets in the evening skies. Saturn, the ringed planet stands to the right of the dimmer star Spica in Virgo in the lower SW sky at nightfall.
Mars appears to be moving fast towards a meeting with the Sun later this summer but not before joining Saturn in the southwest evenings. Between the 23rd and the 25th, watch a thin crescent moon first hang below Mars, and then the Spica-Saturn pair.
For the real sky showpiece this month, we must turn to the early morning sky, where Venus is now a beacon before dawn, appearing brighter even than the biggest planet in the solar system Jupiter, which just happens to be perched above it. By July 12 the goddess of love will be at its brightest it can ever get in our skies – only the Sun and moon can outshines the planet.
But first on July 9 the orange star Aldebaran – the lead member of the constellation Taurus – the Bull, will pair up with Venus.
The two will appear less than a degree apart – that’s less than the width of your finger at arm’s length. Remember however that their proximity is just an optical illusion – while Venus is a mere 57 million km from Earth, Aldebaran is a respectable 65 light year distant.
The best sky show in my opinion however will be on the 15th, when a waning crescent moon will form a neat triangle formation with Jupiter and Venus at dawn. That’s something you don’t want to miss as it will look really pretty just with the unaided eyes.
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Astronomers around the world have their telescopes and cameras pointed to a certain corner of the late summer night sky occupied by the Sagittarius constellation. That’s because on June 26, 2012 backyard astronomers witnessed a new star that became visible within the northwest corner of the mythical archer’s stellar patten, where none had been seen before.
While it’s still early on, experts believe it’s probably a nova – a type of erupting star that can rev up in brightness many orders of magnitude than normal. While not quite as spectacular as a supernova this one appears to be in our local galactic neighborhood, making it at least an easy target for small backyard telescopes.
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With all the excitement of the recent solar eclipse and transit of Venus across the face of the Sun behind us, the starry heavens have a few more cosmic treasures for skywatchers.
Scan the evening skies towards the high eastern horizon this month and explore that ancient classical Greek hero Hercules. While the constellation’s stars are not the brightest, four do make a distinctive wedge-shaped trapezoid of stars marking this superhero’s chest – known as the ‘Keystone’. Look carefully with even binoculars and you’ll find one of the greatest showpieces in the entire night sky; the Great Hercules Cluster or M13.
M13 is a globular cluster made up of a swarm of a half a million stars packed into a ball, stretching over 100 light years across. On a dark moonless night binoculars will easily show it as a fuzzy grey ball, while small telescopes will begin to resolve the edges of the cluster into individual stars.
Located 24,000 light years away, it is one of about 150 globular clusters scattered in a halo around the outside of our own Milky Way galaxy. The light from M13 that you see tonight left the cluster when Earth was still locked in its last ice age.
Meanwhile much closer to home, the planets are putting on their own sky show. The first couple of weeks in June the most challenging of all naked-eye planets makes an appearance very low in the northwestern sky just after sunset. The innermost planet will slowly be rising higher as the planet moves farther away from the Sun – which will be easily visible if you keep an eye on the planet from night to night.
Mercury will position itself within the constellation Gemini in June and on June 21st will sitting on top of the waxing crescent Moon. The cosmic pair will be separated by about 6 degrees – a little more than the width of your three middle fingers at an outstretched arm.
Then as an extra observing challenge on June 24 the little planet will appear to line up with the two brightest stars Castor and Pollux very low towards the horizon just after sunset. A pair of binoculars will help you track down all three.
The red coloured Mars is high in the southwest evening sky and appears between two bright, white stars. To its right is 78 light year distant Regulus. While to the far lower left of Mars you will find the ringed jewel of the solar system, Saturn in the constellation Virgo. The bright star below Saturn is 263 light year distant Spica.
Not sure which is which? The moon will conveniently point the way starting on June 25,when it first pays a visit to the Red Planet, and then on June 27 and 28 it will glide below Saturn, Spica stellar pair.
Finally for those early bird skywatchers, the two brightest planet – Jupiter and Venus – which earlier this season dominated the evening sky will now appear in the predawn twilight very low towards the eastern horizon by mid- June. Look for the razor-thin crescent moon in a super-close encounter Jupiter low in the east at dawn on June 17.
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