Occultation Path For Delta Scorpii - September 3, 2011 Courtesy of IOTA
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Are you ready for a weekend observing treat? Then get out your binoculars, telescopes, or just your eyes as the Moon passes over a bright star. Who, what, when and where? Come on inside and find out…
On September 3, 2001 the dark limb of the Moon will encounter 2.3 magnitude Delta Scorpii. The event can be seen from the eastern and southern United States to northern Venezuela. But don’t be discouraged if you aren’t right in that “zone”. For observers from roughly New York City through central Texas to Baja California, you’ll have an event called a “graze” – where the star will appear to slide along the edge – or just be mighty close.
When do you need to observe? Thankfully the event takes place in the early evening, starting around 10:30 p.m. Eastern Daylight Savings time. But don’t wait until that moment to begin your observations! Get your equipment set up in advance and consult with this IOTA page for precise times and locations.
What do you need to observe an occultation? In this circumstance, the Moon isn’t quite half lit, so the glare won’t be so bad that you can’t observe with your eyes alone. However, a pair of binoculars or a small telescope will make the event far more interesting! For even more fun, take along an accurate watch and time it yourself. If you are in the occultation path, watch to see if Delta disappears and reappears behind a crater rim. Then watch as the whole scene shifts west and the star emerges again!
The timing couldn’t be better. A new supernova, named PTF11kly, which was discovered on August. 24, 2011 is continuing to brighten and should be visible to backyard astronomers this weekend using just a pair of binoculars. It’s not quite naked-eye material but this is an exciting opportunity for amateurs (as well as the pros!) to view a supernova first-hand. Of course, if your backyard is full of light, the best option is to go to an area with darker skies, and you’ll be able to see it much better. Astronomers say PTF11kly will likely continue to shine for some time, and be at its brightest on about Sept. 9, 2011.
In this video Peter Nugent, an astrophysicist from Lawrence Berkeley National Labs explains just how to find this star that exploded about 21 million light years away.
It’s time for the Perseid Meteor Shower and you want to bag some meteors (shooting stars), but how? Maybe you just want to know where and what time to look, or perhaps you are having a Perseid party and you want everyone to have a great time.
If so, then please read on…
First, you don’t need a telescope or binoculars or any high tech equipment. You just need your own eyes and glasses if you wear them.
It’s a good idea to be away from bright lights and if possible have a red light torch or red flashlight, but most importantly try to get your eyes adapted to the dark.
Bright light will instantaneously ruin dark adaption so shining flashlights into faces is a big no-no and looking directly at the Moon isn’t going to help either. Position yourself so you don’t get the Moon in your view.
The Perseids don’t rain down out of the sky; they appear every few minutes and this year, you may only see the rarer bright ones and very bright fireballs due to the full Moon that will be up, and the glare it will unfortunately provide. But if you can get in a good position to avoid the glare, sit back and wait to see some meteors. This is totally worth the wait, but you need to be comfortable or you will give up, go indoors and not see any.
The best bet is to get a reclining garden chair or airbed or something similar to lay back and relax upon. Lots of people put those yard trampolines to very good use and use them as meteor observing platforms.
Dress warmly and cover yourself with blankets or a sleeping bag, August is a summer month, but it can get quite chilly at 1:00am and this will make you give up early too, so stay warm.
Have plenty of drinks and snacks ready so you can basically camp out and not have to keep on getting up, or doing things, because this is when you will, ironically, miss the best fireball of the evening.
Perseid fireball. Image Credit: Pierre Martin of Arnprior, Ontario, Canada.
Where do I look and what direction?
This is the most common question I hear people ask about meteor showers and the answer is very simple.
Follow the above comfort guidelines, look up and away from the Moon and fill your gaze with the sky.
Perseid meteors originate from a fixed point in the sky called the radiant, which is in the constellation of Perseus, however meteors will appear in any part of the sky. You can trace their paths back to the radiant.
After midnight, look towards the East/Northeast part of the your sky to find Perseus. To find it look for the easily identifiable constellation Cassiopeia, the big “W” in sky! Perseus is just below Cassiopeia.
Credit: Stardate/McDonald Observatory
You can draw, take pictures and even video the Perseids, but the simplest and most enjoyable thing is to lay back, relax and be patient and you will be rewarded with a great a view.
The best times to look will be in the dark pre-dawn sky on August 11, 12 and 13, 2011.
You can also follow along with Universe Today and Meteorwatch.org with #meteorwatch on twitter. Ask questions, see what others are seeing, share your experiences and images using the hashtag #meteorwatch
Most of all, enjoy your Perseid experience and have fun!
Every year from late July to mid-August, the Earth encounters a trail of debris left behind from the tail of a comet named Swift-Tuttle. This isn’t the only trail of debris the Earth encounters throughout the year, but it might be one of the most notorious as it is responsible for the annual Perseid meteor shower, one of the best and well-known yearly meteor showers.
Comet Swift-Tuttle is a very long way away from us right now, but when it last visited this part of the Solar system, it left behind a stream of debris made up of particles of dust and rock from the comet’s tail.
Earth encounters this debris field for a few weeks, reaching the densest part on the 11th to 13th August.
The tiny specs of dust and rock collide with the Earth’s atmosphere, entering at speeds ranging from 11 km/sec (25,000 mph), to 72 km/sec (160,000 mph). They are instantly vaporised, emitting bright streaks of light. These tiny particles are referred to as meteors or for the more romantic, shooting stars.
Perseid meteor shower
The reason the meteor shower is called the Perseid, is because the point of the sky or radiant where the meteors appear to originate from is in the constellation of Perseus, hence Perseid.
When the Perseid meteor shower reaches its peak, up to 100 meteors an hour can be seen under ideal dark sky conditions, but in 2011 this will be greatly reduced due to a full Moon at this time. Many of the fainter meteors (shooting stars) will be lost to the glare of the Moon, but do not despair as some Perseids are bright fireballs made from larger pieces of debris, that can be golf ball size or larger.
These amazingly bright meteors can last for a few seconds and can be the brightest thing in the sky. They are very dramatic and beautiful, and seeing one can be the highlight of your Perseid observing experience.
So while expectations may be low for the Perseids this year, keep an eye out for the bright ones and the fireballs. You will not be disappointed, even if you only see one!
Join in on twitter with a worldwide event with Universe Today and Meteorwatch.org just follow along using the hashtag #meteorwatch ask questions, post images, enjoy and share your Perseid Meteor Shower experience.
Be on morning alert from July 26 through July 28 as the Moon, Mars and Aldebaran put on a delightful sky show that doesn’t require any special equipment – just cooperative weather! While this motion picture doesn’t have any sound, what it will have is color to delight the eye.
When it comes to viewing the night sky, most people don’t perceive much color. Things mostly appear black and white – with a little gray on the Moon thrown in for good measure. With experience, most skywatchers easily pick out blue stars and faded green in nebula, but what really gets our hearts ticking is red. And very few stars show that ruddy hue to unaided vision as well as the eye of Taurus the Bull – Aldebaran.
On the morning of July 26th, about an hour before dawn, the waning crescent Moon will be very close to Alpha Tauri and the contrast will make for a spectacular showing. The following morning, it will hover just above Mars and slide into position just below on July 27th. Take the time to really look at what you’re seeing. Of the three principle players, the only one that generates its own light is Aldebaran… the rest are products of reflection. While the star’s russet tone comes from being a cool giant, Mars’ color comes from iron oxide. Not only is the Moon reflecting back sunlight, but you’ll also see the DaVinci effect where the “dark side” is gently illuminated as well.
Don’t be surprised if folks you know ask you what’s going on. Close conjunctions such as this excites the eye! Why? When it comes to our eyes, almost every photoreceptor has one ganglion cell receiving data in the fovea. That means there’s almost no data loss and the absence of blood vessels in the area means almost no loss of light either. There is direct passage to our receptors – an amazing 50% of the visual cortex in the brain! Since the fovea doesn’t have rods, it isn’t sensitive to dim lights. That’s another reason why the conjunctions are more attractive than the surrounding starfields. Astronomers know a lot about the fovea for a good reason: it’s why we learn to use averted vision.
But don’t avert your vision when it comes to enjoying this morning show!
Original News Source: McDonald Observatory StarDate News.
Atlantis crosses the face of the Sun July 21st 2011 at 08:27:48 UT, just 21 minutes before the shuttle's deorbit burn to return to Earth. Credit: Thierry Legault.
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If you’re like me, you were probably wondering if photographer Thierry Legault would have the opportunity to photograph space shuttle Atlantis in orbit during the final mission of the shuttle program. Regular UT readers will recall that Legault has taken several amazing images of the space shuttle and International Space Station from the ground with his specialized equipment, with many spectacular views of the spacecraft transiting across the face of the Sun or the Moon. It took a mad dash across Europe, but he was successful in chasing down the shuttle, capturing it crossing the face of the Sun several times, and once — just in the nick of time (above) — just minutes before the Atlantis’ final deorbit burn.
“I went to Czech Republik, then Germany and now I’m in Netherlands, on my way back to Paris,” Legault said in a note he sent to Universe Today. “The last transit has been taken Thursday morning, just 21 minutes before the deorbit burn, therefore there are chances that is the last image of a space shuttle in orbit.”
Earlier in the mission, he was able to catch the ISS and shuttle just 50 minutes after Atlantis undocked from the station, so his images capture historic moments of the final shuttle mission.
In addition, this stunning view shows Atlantis docked to the ISS:
Atlantis during the STS-135 mission docked to the International Space Station, July 15, 2011. Credit: Thierry Legault.
Legault said this solar transit of Atlantis docked to the ISS was taken on July 15th from France (Caen, Normandy). Transit duration: 0.7s. ISS distance to observer: 520 km. Speed in orbit: 7.5km/s (27000 km/h or 17000 mph).
Atlantis appears on four images as it crossed the Sun, in this composite image. Credit: Thierry Legault. Click for larger version
Four images of Atlantis crossing the face of the Sun taken on July 21st 2011 at 08:27:48 UT, and combined into one image. The images were taken just 21 minutes before Atlantis’ deorbit burn, from the area of Emden, NW Germany. Transit duration: 0.9s. Distance to observer: 566 km. Speed in orbit: 7.8 km/s.
A Calsky image below shows the last miles of Atlantis in orbit with the transit site in Europe, the deorbit burn position and the landing site in Florida. Image courtesy Thierry Legault. Atlantis and the ISS side by side, 50 minutes after undocking. Credit: Theirry Legault. Click for larger version, and full version of the Sun's face.
Solar transit taken on July 19th at 7:17 UT from Czech Republik (North of Praha), showing Atlantis and the ISS side by side, 50 minutes after undocking. Transit duration: 1s. ISS distance to observer: 676 km.
Many thanks to Thierry Legault for sharing his images with Universe Today, and taking us along on the ride of his travels across Europe to capture the final space shuttle mission in a way that only he can!
For astronomers and physicists alike, the depths of space are a treasure trove that may provide us with the answers to some of the most profound questions of existence. Where we come from, how we came to be, how it all began, etc. However, observing deep space presents its share of challenges, not the least of which is visual accuracy.
In this case, scientists use what is known as Active Optics in order to compensate for external influences. The technique was first developed during the 1980s and relied on actively shaping a telescope’s mirrors to prevent deformation. This is necessary with telescopes that are in excess of 8 meters in diameter and have segmented mirrors.
Definition:
The name Active Optics refers to a system that keeps a mirror (usually the primary) in its optimal shape against all environmental factors. The technique corrects for distortion factors, such as gravity (at different telescope inclinations), wind, temperature changes, telescope axis deformation, and others.
The twin Keck telescopes shooting their laser guide stars into the heart of the Milky Way on a beautifully clear night on the summit on Mauna Kea. Credit: keckobservatory.org/Ethan
Adaptive Optics actively shapes a telescope’s mirrors to prevent deformation due to external influences (like wind, temperature, and mechanical stress) while keeping the telescope actively still and in its optimal shape. The technique has allowed for the construction of 8-meter telescopes and those with segmented mirrors.
Use in Astronomy:
Historically, a telescope’s mirrors have had to be very thick to hold their shape and to ensure accurate observations as they searched across the sky. However, this soon became unfeasible as the size and weight requirements became impractical. New generations of telescopes built since the 1980s have relied on very thin mirrors instead.
But since these were too thin to keep themselves in the correct shape, two methods were introduced to compensate. One was the use of actuators which would hold the mirrors rigid and in an optimal shape, the other was the use of small, segmented mirrors which would prevent most of the gravitational distortion that occur in large, thick mirrors.
The New Technology Telescope (NTT) pioneered the Active Optics. Credit: ESO/C.Madsen. Bacon
Other Applications:
In addition to astronomy, Active Optics is used for a number of other purposes as well. These include laser set-ups, where lenses and mirrors are used to steer the course of a focused beam. Interferometers, devices which are used to emit interfering electromagnetic waves, also relies on Active Optics.
These interferometers are used for the purposes of astronomy, quantum mechanics, nuclear physics, fiber optics, and other fields of scientific research. Active optics are also being investigated for use in X-ray imaging, where actively deformable grazing incidence mirrors would be employed.
Adaptive Optics:
Active Optics are not to be confused with Adaptive Optics, a technique that operates on a much shorter timescale to compensate for atmospheric effects. The influences that active optics compensate for (temperature, gravity) are intrinsically slower and have a larger amplitude in aberration.
Artist’s impression of the European Extremly Large Telescope deploying lasers for adaptive optics. Credit: ESO/L. Calçada/N. Risinger
On the other hand, Adaptive Optics corrects for atmospheric distortions that affect the image. These corrections need to be much faster, but also have smaller amplitude. Because of this, adaptive optics uses smaller corrective mirrors (often the second, third or fourth mirror in a telescope).
Two white dwarfs have been discovered on the brink of a merger. In just 900,000 years, material will start to stream from one star to the other (as shown in this artist's conception), beginning the process that may end with a spectacular supernova explosion. Watching these stars fall in will allow astronomers to test Einstein's general theory of relativity as well as the origin of a special class of supernovae. Credit: David A. Aguilar (CfA)
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“Well, I don’t know, but I’ve been told… You never slow down, you never grow old.” Well, Tom Petty might not ever grow old, but stars do. In this case it’s a pair white dwarf stars and they’re locked in a death dance that has them spiraling around each other in just 13 minutes. Astronomers estimated that in about 900,000 years the pair will merge… and what a party that will be!
Traveling in an orbit that’s currently carrying them at 370 miles per second (600 km/s), these two burnt-out stellar cores are heading towards a supernova ending. Right now the brighter of the pair is about the size of Neptune and carries about one quarter of our Sun’s mass. Its companion contains twice as much mass and is about the size of Earth. What’s peculiar is the incredible speed at which they are converging.
“I nearly fell out of my chair at the telescope when I saw one star change its speed by a staggering 750 miles per second in just a few minutes,” said Smithsonian astronomer Warren Brown, lead author of the paper reporting the find.
Using the MMT telescope at the Whipple Observatory on Mt. Hopkins, Arizona, researchers have been looking for just such eclectic white dwarf pairings. Because of their close proximity, they can only be separated spectroscopically and their relative motions then determined. Fortunately, this unusual set are eclipsing, doing their two-step at a very predictable rate. “If there were aliens living on a planet around this star system, they would see one of their two suns disappear every 6 minutes – a fantastic light show.” said Smithsonian astronomer and co-author Mukremin Kilic.
What’s really cool about this observing project is its implications as related to Einstein’s theories. Their movements should create wrinkles in the fabric space-time. These gravitational waves pull away at the energy – allowing the pair to get closer at each pass and their orbits to accelerate.
“Though we have not yet directly measured gravitational waves with modern instruments, we can test their existence by measuring the change in the separation of these two stars,” said co-author J. J. Hermes, a graduate student at the University of Texas at Austin. “Because they don’t seem to be exchanging mass, this system is an exceptionally clean laboratory to perform such a test.”
Just as soon as the pair emerges from behind the Sun, observing will begin again. Some models predict merging white dwarf pairs of this type could be a rare class of unusually faint stellar explosions called underluminous supernovae – or just the source of many other kinds of supernovae. “If these systems are responsible for underluminous supernovae, we will detect these binary white dwarf systems with the same frequency that we see the supernovae. Our survey isn’t complete, but so far, the numbers agree,” said Brown.
What can we say besides, “Last dance with Mary Jane… One more time to kill the pain… I feel summer creepin’ in.”
A local famer from Afghanistan looks at the night sky through a telescope. Credit: Saeid Aghaei.
Most amateur astronomers take for granted that they can just go outside and enjoy viewing the night sky without encountering many problems — aside from keeping mosquitoes at bay or fixing equipment malfunctions. But in order for amateur astronomers in Afghanistan to simply set up a telescope in a dark region, they have to deal with more serious complications, such as making sure the area is clear of land mines, not arousing the suspicions the Taliban or the local police, and watching out for potential bombing raids by the US/UK/Afghan military alliance. But amateur astronomers like Saeid Aghaei and Yunos Bakhshi take those risks in stride just so they can share the beauty of the night sky with the Afghani people.
Aghaei is an amateur astronomer and a science and technology columnist from Neyshabur, Iran. For several years, he has been translating Universe Today articles on space and astronomy and publishing them in his local newspaper in Iran. But he is now in Kabul, Afghanistan working with his Afghan friend Yunos Bakhshi, to help establish and nurture the Afghanistan Astronomy Association. Bakhshi is one of the founders and is currently head of the organization.
This organization was initiated during the International Year of Astronomy in 2009, but has faced difficulties; not only from the upheaval the country is experiencing but because of the limited scientific exposure the general public has in Afghanistan. Bakhshi said there is confusion between astronomy and astrology (which, unfortunately happens everywhere) and also, due to limited access to the internet and illiteracy among the majority of Afghanis, many don’t see the practical applications of studying the sciences.
But on their website, the Afghan Astronomy Association says they hope to help make it easier to learn more about astronomy for all Afghans with different levels of knowledge on the subject.
“We believe, that astronomy can solve one of the background problems of Afghanistan; the struggle over the real ownership of this country, which lasts more than three decades. We try by wiping off the gun smoke from Afghanistan sky, to show the beauty and mysterious of Universe to all Afghans; so they will understand that this world, this blue planet and even this sun with its planets are just a tiny point in the Grand picture of Universe that no one is better than other; except by knowledge and moral values.”
Bakhshi said he and Aghaei are “committed to disseminate the astronomy knowledge among ordinary Afghans, mainly school children.” They are helping the cause by doing what they call “Adventure Astronomy” – basically braving dangerous situations to expose more Afghanis to astronomy.
The two shared their experiences from a recent night of skywatching in Afghanistan:
A view of the night sky about 20 km from Kabul, Afghanistan, with light pollution from the Bagram Military Base. Credit: Yunos Bakhshi.
At the end of last week, they traveled about 20 km from Kabul with a group of interested people. Even at that distance they experienced light pollution from the city and the American military base in Bagram. “Our observation site was a small farm not so far from the main highway,” Aghaei told Universe Today in an email. “It was a peaceful and calm place (based on local standards): all land mines are cleared or exploded, no sign of Taliban, because two days before they attacked Intercontinental Hotel in Kabul and based on our experiences and statistics (nonofficial), they would rest for one or two weeks. The only concern of us, even from the start of night was the battery charge (energy supply). But our presence with suspicious equipments triggered the local farmers’ concerns.”
After aligning the telescope, a car slowly approached, shining its lights on Aghaei and his friends, which included scientist Yunos Bakhshi and another amateur astronomer, and several Afghani people who were just interested in seeing the night sky.
“Suddenly we found ourselves surrounded by a group of gunmen,” Aghaei said. “We explained that we are astronomers, but the local police commander approached so to be sure that we are not terrorists and that our telescope had no military application and it is not a rocket launcher. We invited him to watch M4 Star Cluster, but he didn’t like it and said that his own binocular is more powerful. He told us were a group of half-witted and nothing else. One of the police registered our names and listed all our equipment.”
This frightened some of people who had joined the astronomers and many of them left.
“We explained that in most cases national and international forces do not mistake and target civilians, but we couldn’t assure them, and most of them (who for sure were saner than us) escaped and left us three astronomers alone,” Aghaei said.
Just when they finally had a chance to start observing and do some night sky photography, the sky was lit up from bright lights from the Bagram Military Airbase, one of the big bases of US forces in Afghanistan.
“We were sure that the American forces launched some kind of military training and that is why they simulated the daylight condition.” Aghaei said. “After one hour another issue halted our observation, saving our life: two military helicopters on their way to the Bagram military base, with no light crossed the sky over us. At first we were ready to risk our life but not turn off the telescope remote, because once again alignment could take a lot of time, but finally we preferred to stay alive. We heard that in many occasions by mistake pastors were attacked by these iron birds, and this issue forced us not to play Russian roulette.”
Aghaei quickly looked one last time at M27 and then turned off the telescope, lay down on the ground and didn’t move. The trio realized only later that the military could have had night vision cameras and the astronomers could have been spotted. Aghaei also said with this experience, he is going to propose to telescope companies that they invent a special button to switch off the remote control light in situations like this, at least for Afghan astronomers.
But their adventures weren’t over for the night. Next, a pack of dogs approached and began barking loudly. Aghaei said they dispersed the dogs by inventing a new application for green laser pointers.
Ultimately, the group was able to do what they hoped most, to take some astronomical images from their observations. Here is their image of M27:
Saeid Aghaei’s first experience of deep sky photography in Afghanistan, showing M27, the Dumbbell Nebula. Credit: Saeid Aghaei.
Aghaei and Bakhshi reflected on their experiences.
“Finally the night passed and close to dawn we arrived to the main entrance check point to Kabul city. We were thinking about our adventures and want to say that, no matter what kind of telescope or photography equipment you have, even it is not important you have got the first deep sky photo or TWAN-style (The World At Night) photo of this country (we had such experience that night), but it was important that we saved our life. We realized that for any next observation program, the main challenge is security concern and this factor will determine where ever we want to go for next our observation.”
But – no question — they will be going again, and Aghaei says, “Anyone who wants to experience such adventure we highly appreciate and welcome.”
Find out more about the Afghan Astronomy Association at www.kabulsky.com
Panoramic view of Noctulucent Clouds from Kendal Castle in the UK. Credit: Stu Atkinson
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Mysterious “night shining” or Noctilucent Clouds are beautiful to behold, and here are some gorgeous examples what skywatchers in the UK have been experiencing. Stu Atkinson took this stunning panoramic view from Kendal Castle. (Click image for access to a larger version). NLCs are usually seen during the summertime, appearing at sunset. They are thin, wavy ice clouds that form at very high altitudes and reflect sunlight long after the Sun has dropped below the horizon. Scientists don’t know exactly why they form, and they seem to be appearing more and more in recent times.
See more below.
Science writer Will Gater also had a great view of NLCs this morning. Click the image to see his animation, or see more of his images and animations at his website post.
NLCs seen over the UK on July 1, 2011. Click to see animation. Credit: Will Gater
Another view of Noctilucent Clouds from Kendal Castle in the UK on July 1, 2011. Credit: Stu Atkinson
