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For education orders please call 1-877-290-8256. Welcome again to our monthly newsletter with features on exciting celestial and earth science events, product reviews, tips & tricks, and a monthly sky calendar. We hope you enjoy it!
This year Astronomy Day falls on Saturday May 7, and there will be events all around the world to celebrate our favorite hobby. There's a good summary of what Astronomy Day is all about, along with listing of events all around the United States, on this web page <astroleague.org/al/astroday/astroday.html>. And here's a similar page for Canadian events <rasc.ca/astroday/resources.shtml>. If you're new to astronomy, Astronomy Day gives you a chance to experience a star party, and look through telescopes of different kinds. If you're an old timer, you're probably already participating in your club's events, but there's an opportunity here for everyone to help get newcomers involved. Contact your local school or library to see if they are interested in hosting an event. There are plenty of resources available online, including our very own Welcome Guide to Astronomy, which you can download, print out, and distribute free of charge. Probably the greatest experience you can offer to a newcomer is the chance to look through a telescope at some favorite objects in the sky. Even though we astronomy regulars may drool over faint galaxies, such tough objects are usually lost on the general public. From my experience at dozens of star parties, I can guarantee that the most popular objects for most people are the Moon and planets, especially Jupiter and Saturn. On May 7, a 5-day-old Moon will be perfectly placed for viewing with any telescope, as will the ringed planet Saturn. I like to point out Saturn's brightest moons in addition to the more obvious rings. Starry Night® will print out a view of Saturn and its moons to help you identify them. Bright Titan, easily visible in any telescope, will be at the west side of the planet, and Rhea, the second brightest Moon will be on the east side.
Double stars are popular targets at Astronomy Day star parties. Algieba, located directly above Regulus in Leo, is one of the finest double stars in the sky. The information in Starry Night® will give you some interesting things to tell people about this pair of stars. They are located 126 light years away from us and revolve around each other once each 620 years. A magnification of 100x should be enough to split these two stars. Open clusters are popular showpieces at low magnification. The Beehive in Cancer (Messier 44) is a fine example. Cancer is a dim constellation, located half way between Regulus in Leo and Castor and Pollux in Gemini. The Beehive actually outshines all the stars in Cancer, making for a really spectacular view in a wide-field eyepiece or even binoculars.
If you have a large aperture scope available, three of the biggest and brightest globular clusters will be rising in the east: Messier 3 in Canes Venatici, Messier 5 in Serpens, and Messier 13 in Hercules. Again, refer to Starry Night® to get some interesting information to pass on to your visitors. Have a great astronomy day and be sure to check our online store on May 7th for a great way to share your passion with others! Geoff Gaherty
Optimized for projection, Starry Night Podium provides an intuitively designed interface on your computer while projecting an impressive, uncluttered view. You can see how the sky will look tonight, tomorrow, or far into the past or future. You can view the stars as they appear from your own backyard, from a country on the other side of the world, or from another planet. You can witness a total eclipse from the Moon, watch the Sun set from the surface of Mars, ride a comet or even venture out into the realm of galaxies. You are limited only by your curiosity.
Fly through the wonders of Deep Space on the large screen Starry Night Podium's comprehensive data library gives you access to thousands of astronomical objects, including distant galaxies, extra-solar planets, comets and satellites. You'll get 250 ready-to-use interactive simulations, 100 mini-documentaries, 25 concept diagrams that help explain abstract concepts and phenomena, and much more. You can even add your own simulations, videos and images to help create memorable explorations of the universe. This top of the line product was designed to be appreciated by any audience. There is no other package like it on the market and, for a short time, we are making it available at a savings of over $100. For an unparalleled astronomical experience, you must have Starry Night Podium.
As its name suggests, this asteroid was discovered in 2005. It is about 400 meters in diameter and roughly spherical as its radar image of April 19, 2011 suggests.
Radar image of asteroid 2005 YU55. Image credit: NASA/Cornell/Arecibo Analysis of early data indicated that this object could pass dangerously close to Earth with a collision being possible. Why should this be a problem? About 50 million years ago, a 50 meter wide asteroid fragment impacted in what is now northern Arizona and left a 1200 meter wide and 170 meter deep impact crater.
Meteor Crater. Image courtesy of the U.S. Geological Survey Due to the potentially catastrophic consequences of such collisions, NASA maintains a Near Earth Object Program which identifies and tracks comets and asteroids entering Earth's neighborhood. With their relatively low mass, these objects have their orbits slightly altered by the gravitational attraction of any nearby large planets (especially Jupiter). 2005 YU55 is such an asteroid. It is part of the Apollo group whose fairly elongated orbits cross the Earth's orbit. It is therefore possible that Earth and 2005 YU55 can have a "close encounter" twice during each orbital cycle.
2005 YU55 and the Inner Solar System And indeed, on November 8, 2011, the asteroid will pass the Earth at about 85% of the Moon's distance. An actual collision, however, has been ruled out by recent observations—it appears that earthlings will be safe from this threat for at least the next hundred years.
Earth and 2005 YU55 on November 8, 2011 But how many more of these N(ear) E(arth) O(bject)s are there out there? Check out the latest list of Potentially Hazardous Asteroids at the IAU's Minor Planet Center web page But remember that this list contains only known objects! It is quite possible that at this very moment a chunk of rock left over from the formation of the solar system is quietly passing a little too close to Jupiter and is gently nudged into a slightly altered orbit as it heads toward the inner solar system. Will it become a NEO? Will we spot it in time if it becomes a threat? Can we do anything about it? Interesting questions and possible "earth-shattering" answers! Further Study 1. Where do asteroids come from? Answer to last month's question:
Herb Koller
Newly updated lists of asteroids, comets, and satellites are released every morning. They include a few hundred of the brightest and most interesting objects. For most users of Starry Night this is more than adequate. Near Earth Objects Near Earth objects, primarily asteroids, are often discovered only hours before they pass near to Earth, so sometimes get missed in the daily asteroid updates. I have observed a number of near Earth asteroids, and sometimes had to add them to Starry Night manually. Orbital elements of these objects are often published after the Starry Night updates are posted each morning, and sometimes are updated several times between discovery and closest passage. This is partly because the orbits are improved as more observations are collected, and partly because the orbits themselves change significantly as the objects becomes subject to perturbations by Earth's gravity. One excellent source of up-to-date orbital elements for near-Earth asteroids and new objects is the IAU's Minor Planet Center: This is very easy to use. Enter the IDs of objects whose orbits you want in the box, one entry per line. For example, I entered two objects which will be of interest later in the year, a near-Earth asteroid and a periodic comet:
Scroll down to the bottom of the page to “Format for elements output:” and click on the button for Starry Night. Click the button “Get ephemerides/HTML page” and a file named “elements.txt” will be downloaded automatically. This file contains a line for each object requested:
If you open the Comets.txt file (found in the Sky Data folder—on a Mac, Control-click on the Starry Night application, select “Show Package Contents” then follow the path Contents:Resources:Sky Data) you can simply paste the comet entries into the file. Unfortunately, the file format for Asteroids has changed, so you must enter these elements by copying and pasting into the dialog brought up by choosing “New Asteroid Orbiting Sun...” from the File menu in Starry Night. Most data can be entered in the “Orbital Elements” window, except for Magnitude, which is entered under “Other Settings.” The result should look like this:
Notice how, as you enter the orbital elements, the orbit gradually forms before your eyes. Another source of orbital elements is NASA's Jet Propulsion Laboratory: Often with near Earth asteroids, these two sources will give slightly different orbital elements. In that case, I usually load both sets of elements into Starry Night and mark them “MPC” and “JPL” to distinguish between them. It's often fascinating to compare the two orbital paths in Starry Night. Once the elements are entered in Starry Night, it becomes easy to figure out that Asteroid 2005 YU55 will pass within 330,591 km. of Earth on the evening of 2011 November 8. This will put it closer to Earth than the Moon! It should be around 9th magnitude, easily visible in a small telescope or even binoculars.
Notice how 2005 YU55 covers a wide swath of sky: 3 constellations in just 5 hours. This is a perspective effect because it is so close to Earth. Observing it is not as simple as it seems however. Having observed a number of near-Earth asteroids, I've learned that they're rarely exactly where they're predicted to be, because, as they near the Earth, their orbits get severely perturbed. What I've found, in several cases, is that the track plotted by Starry Night is correct, but the asteroid has been accelerated along its track so that it is 5 or 10 minutes ahead of its predicted position. The trick for finding it is to pick a spot about 10 or 15 minutes ahead of its predicted position on the track, and then wait for it to come along. This “ambush” technique has worked very well for me, and has enabled me to catch several near-Earth asteroids. Comet 45P/Honda-Mrkos-Pajdusáková is another interesting case: This periodic comet was discovered in 1948, and will also be passing very close to Earth, 8,990,000 km., on 2011 August 15. Unfortunately, it will be visible only in the Southern Hemisphere while at its closest. Geoff Gaherty
Observe M81 and M82 M81 and M82 are perhaps the most famous pair of galaxies in the sky and both can be seen in the same low magnification field of view. Both are spiral galaxies but M81 is nearly face on, while M82 is edge on. The contrast offered by these two galaxies is one of the visual delights of the night sky. M81 and M82 are separated by only 150,000 light years. Tens of millions of years ago, the larger (and ten times as massive) M81 passed close by its smaller neighbor, inducing a round of starburst formation in M82. It also led to the birth of over 100 globular clusters, and disrupted the appearance of M82, so much that it is sometimes classed as an irregular galaxy instead of a spiral galaxy. While quite faint in visible light, M82 is the brightest galaxy in the sky in the infrared region. Pedro Braganca
This part of the sky floats above the celestial north pole so there isn't a lot of interstellar dirt obscuring our lines of sight toward some interesting, though faint, galaxies. M51, the Whirlpool Galaxy, is a good example of quantity equaling quality: time spent with M51 reaps rewards, with brief flashes of clarity that slowly build in your mind's eye to a fascinating whole. Although faint, two cores are visible; the second, less bright core is that of NGC 5195, a smaller galaxy interacting gravitationally with its large neighbor. Get yourself as dark adapted as possible. Averted vision will bring out hints of the spiral arms. Some nights are better than others. M63 and M94 are two more spiral galaxies, less spectacular, but interesting to compare with each other and with M101 and M51. Cor Caroli is a nice double even in small scopes. Note the color difference. Cor Caroli has only 2.3 times the radius of our sun yet shines a hundred times as bright. NGC 4631 is also known, quite properly, as the Whale Galaxy. It's faint, huge, elongated and completely awesome in the eyepiece. NGC 4449 is an irregular galaxy in Canes Venatici. In comparison to the Whale, this galaxy is elongated, kinked, and a bit weird looking. Moving away from some of the fainter targets, M106 is a big galaxy with a bright disc. Easy hunting. Finally, with an estimated half-million stars, M3 is one of the sky's finest globular clusters. While visible to the naked eye, the more photons your telescope or binoculars can capture, the more stars you'll be able to resolve. Sean O'Dwyer
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MAY 2011
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