The tuning of a telescope is actually called "collimation," and Sky and Telescope shows you how:
To get your telescope well collimated, here is what you need to accomplish:
Step 1: Center the secondary mirror on the axis of the focuser drawtube.
Step 2: Aim the eyepiece at the center of the primary mirror.
Step 3: Center your primary mirror’s sweet spot in the eyepiece’s field of view.
In most cases, only the last of these three steps will need to be repeated regularly; the first two are more or less set-and-forget operations. Now let’s get to the nuts and bolts of actually collimating your reflector
Normally the Ursids meteor shower isn’t that spectacular, and when it peaks this year around the 22nd of December, a bad moon will make viewing it difficult in Europe and Asia, and it will be daytime in North America. So why is Peter Jenniskens, a meteor astronomer at the Carl Sagan Center and SETI Institute, travelling all the way to the North Pole to view it this year?
Peter explains that it’s the presence of Comet 8P/Tuttle (pictured above) within the shower, and a long-standing mystery or the Ursids’ outbursts, that are bringing him high over the North Pole:
We are preparing to visit the North Pole on December 22, to see an unusual meteor shower called the Ursids. This meteor shower radiates from the constellation known as the Little Dipper: Ursa Minor. This minor shower is quite unremarkable in most years, but this year the parent comet 8P/Tuttle is approaching, and it has a strong Perseid-level shower in store for us. We think. We predict a peak time around 20 – 22.2 Universal Time and a width of 5 to 8.5 hours at half the peak rate.
Unfortunately, that means that North America is not a good place to be, for our purpose. The outburst will happen during our daytime. Best viewing will be in Asia and Europe. Even from those locations it won’t be easy to see this shower, because of a bad moon that night, and frequent bad weather in December…
The Ursid outburst is too rare an opportunity to miss, though, because the comet returns only every 13.6 years. This time around, the comet comes closer to us than ever before, at least since it was discovered in 1790, passing at only 0.25 AU on January 5….
The Ursid outbursts are somewhat of a mystery. They have been heard, more than seen, in the years around past returns of the comet, by people listening for distant radio stations. Each time a meteor appeared in the cold winter sky, it would create a trail of ions, which reflected radio waves to the observer. They would hear a brief "ping". While counting those pings, it was clear to those listeners that something unusual was happening on December 22 in some years.
In collaboration with Esko Lyytinen of Helsinki, Finland, and Jeremie Vaubaillon of Caltech, I investigated these reports, and we discovered that the dust may have been ejected by comet Tuttle around AD 300 to 900, or perhaps earlier. Results will be published in the upcoming December issue of the Journal of the International Meteor Organization. It takes a long time for the dust to move from an orbit similar to that of the comet into an orbit that can hit Earth. Close encounters of Jupiter near the ascending node of the comet orbit seem to play an important role, especially when they occur shortly after the dust has been ejected and is still concentrated in space. The dust itself is most affected when its motion around the sun "rings," or resonates, with that of Jupiter.
The upcoming outburst is a great opportunity to test this model. When the Earth travels through the stream of dust, we may hope to see the dominance of some particular returns of the comet in the past, when all the dynamics worked in our favor. This could cause a particular peak time and rate profile of the shower.
To investigate this, we are hoping for an opportunity to observe the outburst from a Gulfstream V aircraft in a mission similar to our campaign to study the September 1 Aurigids. If approved, the Ursid flight will be a long 16-hour mission, involving one aircraft, departing from NASA Ames Research Center in the early morning of December 22nd. The plane will fly north-west towards Alaska, land in Anchorage for a refuel stop, and then continue on to follow the Earth’s shadow, fly over the Arctic and turn towards Canada to return at Ames just after sunset. We don’t need to fly all the way to the North Pole, just far enough north to stay in darkness all the time. The aircraft will follow the Earth’s rotation, making the meteors fall from a radiant high in the sky throughout the mission. The moon will stay low on the horizon on one side of the plane.
16 hours? That’s a long flight in a cold place. The flight path of Jenniskens’ Gulfstream V can be found here and here; the Federation des Astronomes Amateurs du Quebec also has some good finder charts here. Finally, for spotting Comet 8P/Tuttle, this finder chart is helpful.
In September, we discussed the launch Japan’s lunar study, KAGUYA – what many consider the most sophisticated lunar exploration mission in the post-Apollo Era. KAGUYA is already showing results, bringing us the first high definition image of Earth (link):
The photograph was taken from a distance of 110,000 km– hundreds of times further away from Earth than any spaceship with similar capabilities had ever been. After taking these breathtaking images, KAGUYA went on to orbit the Moon and then released a baby satellite as part of its ongoing lunar exploration mission.
Until recently there were only three possible ways to photograph Earth from a distance of several hundred kilometers- via a Space Shuttle, via the International Space Station (ISS) or via orbiting satellites. Now, thanks to the KAGUYA Lunar explorer, which was launched by the Japan Aerospace Exploration Agency (JAXA) and the Japan Broadcasting Corporation (NHK), we can see Earth in its full glory, as it is from afar.
In September 2007, JAXA launched the KAGUYA (SELENA: Selenological and Engineering Explorer) into space. It is composed of a main orbiting satellite and two smaller satellites in polar orbit, and is equipped with instruments for scientific investigation of the Moon.
KAGUYA’s (SELENA) main mission is to collect scientific data from the Moon that will be used to explore the possibility of utilizing the Moon in the future. The three HD CCD 2.2 Mega-pixel cameras onboard the KAGUYA were developed by Japan’s Broadcasting Corporation specifically for this mission. In addition to the cameras, the ship is equipped with 13 other scientific instruments which will be used to explore the Moon.
The abovementioned image was processed from a high resolution video that was shot periodically over eight minutes, on September 29th, 2007. When looking at the image, one can see the outlines of the west coast of South America quite distinctively.
This is a still image taken out from the first moving image shooting when the KAGUYA flew from the northern area of the Oceanus Procellarum to the centre of the North Pole. As the altitude near the North Pole is high, the angle of the coming sunlight was lower, thus the shade of the crater topography looks long in the image. The moving image was taken at 4:07 AM on 31 October 2007 (JST) by eight-fold speed intermittent shooting (eight minutes is converged to one minute) from the KAGUYA, and the data was received at the JAXA Usuda Deep Space Centre on the same day.
A video of the moon captured by the HDTV camera is available here.
The Chandra X-Ray Observatory, run by the Smithsonian Astrophysical Observatory in Cambridge, MA, helped astronomers find a huge black hole orbiting a buddy star. Image above: artist’s representation of M33 X-7, a binary system in the nearby galaxy M33 (Credit: Illustration: NASA/CXC/M.Weiss; X-ray: NASA/CXC/CfA/ P.Plucinsky et al.; Optical: NASA/STScI/SDSU/J.Orosz et al.). Check out the Chandra blog, too.
Astronomers have located an exceptionally massive black hole in orbit around a huge companion star. This result has intriguing implications for the evolution and ultimate fate of massive stars.
The black hole is part of a binary system in M33, a nearby galaxy about 3 million light years from Earth. By combining data from NASA’s Chandra X-ray Observatory and the Gemini telescope on Mauna Kea, Hawaii, the mass of the black hole, known as M33 X-7, was determined to be 15.7 times that of the Sun. This makes M33 X-7 the most massive stellar black hole known. A stellar black hole is formed from the collapse of the core of a massive star at the end of its life.
"This discovery raises all sorts of questions about how such a big black hole could have been formed,” said Jerome Orosz of San Diego State University, lead author of the paper appearing in the October 18th issue of the journal Nature.
M33 X-7 orbits a companion star that eclipses the black hole every three and a half days. The companion star also has an unusually large mass, 70 times that of the Sun. This makes it the most massive companion star in a binary system containing a black hole.
"This is a huge star that is partnered with a huge black hole," said coauthor Jeffrey McClintock of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Eventually, the companion will also go supernova and then we’ll have a pair of black holes."
The properties of the M33 X-7 binary system – a massive black hole in a close orbit around a massive companion star – are difficult to explain using conventional models for the evolution of massive stars. The parent star for the black hole must have had a mass greater than the existing companion in order to have formed a black hole before the companion star. Such a massive star would have had a radius larger than the present separation between the stars, so the stars must have been brought closer while sharing a common outer atmosphere. This process typically results in a large amount of mass being lost from the system, so much that the parent star should not have been able to form a 15.7 solar-mass black hole.
The black hole’s progenitor must have shed gas at a rate about 10 times less than predicted by models before it exploded. If even more massive stars also lose very little material, it could explain the incredibly luminous supernova seen recently as SN 2006gy. The progenitor for SN 2006gy is thought to have been about 150 times the mass of the Sun when it exploded.
"Massive stars can be much less extravagant than people think by hanging onto a lot more of their mass toward the end of their lives," said Orosz. “This can have a big effect on the black holes that these stellar time-bombs make."
Coauthor Wolfgang Pietsch was also the lead author of an article in the Astrophysical Journal that used Chandra observations to report that M33 X-7 is the first black hole in a binary system observed to undergo eclipses. The eclipsing nature enables unusually accurate estimates for the mass of the black hole and its companion.
"Because it’s eclipsing and because it has such extreme properties, this black hole is an incredible test-bed for studying astrophysics," said Pietsch.
The length of the eclipse seen by Chandra gives information about the size of the companion. The scale of the companion’s motion, as inferred from the Gemini observations, gives information about the mass of the black hole and its companion. Other observed properties of the binary were used to constrain the mass estimates.
This animation sequence begins with a wide-field optical image from Kitt Peak of M33, a spiral galaxy about 3 million light years from Earth, and then zooms into a view from the Gemini telescope on Mauna Kea, Hawaii. Next, the view zooms into an even smaller field, from the Hubble Space Telescope, that includes M33 X-7, the most massive known black hole to be formed from the collapse of a star. The final image is a composite of the region around M33 X-7 that contains both the Chandra and Hubble data. (Credit: Kitt Peak: NOAO/AURA/NSF/T.A.Rector; Gemini: AURA/Gemini Obs./SDSU/J.Orosz et al.; HST: NASA/STScI/SDSU/J.Orosz et al.; Chandra: NASA/CXC/CfA/P.Plucinsky et al.)
After "a solid state power switch that was tripped due to a galactic cosmic ray hit", the Cassini-Huygens spacecraft went into safe mode earlier this week. It’s recovered since and the fly-by was very cool:
Mission controllers have since sent commands for Cassini to resume normal transmission, and scientists recovered all the data from the moon flyby despite a nearly 12-hour delay. The spacecraft was expected to be fully functional by week’s end.
Iapetus, the third-largest Saturnian moon, gained science fiction fame in Clarke’s mind-bending novel "2001: A Space Odyssey," that was developed in concert with Stanley Kubrick’s 1968 movie by the same name.
Clarke, who lives in Sri Lanka, surprised the Cassini team with a five-minute video played Tuesday during an internal meeting at NASA’s Jet Propulsion Laboratory. In it, Clarke told scientists he looked forward to viewing photos from the flyby.
Even before Clarke’s taped greeting, scientists waxed poetic about Cassini’s encounter with Iapetus and the fictional Discovery spaceship’s rendezvous with Japetus, as the Saturn moon is known in Clarke’s book.
Video greeting to NASA JPL to mark the Iapetus flyby of Cassini spacecraft: 10 September 2007
by Arthur C. Clarke
Hello! This is Arthur Clarke, joining you from my home in Colombo, Sri Lanka.
I’m delighted to be part of this event to mark Cassini’s flyby of Iapetus.
I send my greetings to all my friends – known and unknown – who are gathered for this important occasion.
I only wish I could be with you in person, but I’m now completely wheelchaired by Polio and have no plans to leave Sri Lanka again.
Thanks to the World Wide Web, I have been following the progress of Cassini-Huygens mission from the time it was launched several years ago. As you know, I have more than a passing interest in Saturn…
And I was really spooked in early 2005, when the Huygens probe returned sound recordings from the surface of Titan. This is exactly what I had described in my 1975 novel Imperial Earth, where my character is listening to the winds blowing over the desert plains overhead.
That was perhaps just a foretaste of things to come! On September 10, if everything goes according to plan, Cassini would give us our closest look at Iapetus – one of Saturn’s most interesting moons.
Half of Iapetus appears as dark as asphalt, and the other half is as bright as snow. When Giovanni Cassini discovered Iapetus in 1671, he could only see its bright side. We had a better glimpse when Voyager 2 flew past in August 1981 – but that was from almost a million kilometres away.
In contrast, Cassini is going to come within a little over one thousand kilometres of Iapetus.
This is a particularly exciting moment for fans of 2001: A Space Odyssey – because that’s where the lone astronaut Dave Bowman discovers the Saturn monolith, which turns out to be a gateway to the stars. Chapter 35 in the novel is titled ‘The Eye of Iapetus’, and it contains this passage: "Iapetus was approaching so slowly that it scarcely seemed to move, and it was impossible to tell the exact moment when it made the subtle change from an astronomical body to a landscape, only fifty miles below. The faithful verniers gave their last spurts of thrust, then closed down forever. The ship was in its final orbit, completing a revolution every three hours at a mere eight hundred miles an hour – all the speed that was required in this feeble gravitation field."
After more than 40 years, I cannot remember why I placed the Saturn monolith on Iapetus. At that time, in the early days of the Space Age, earth-based telescopes couldn’t show much details of this celestial body. But I have always had a strange fascination for Saturn and its family of Moons. By the way, that ‘family’ has been growing at a very impressive rate. When Cassini was launched, we knew of 18 moons. I understand it is now 60 – and counting…I just can’t resist the temptation to say:
My God, it’s full of moons!
But in the movie, Stanley Kubrick decided to place all the actions at Jupiter, not Saturn. Why this change? Well, for one thing it made a more straightforward storyline. And more importantly, the special effects department couldn’t produce a Saturn that Stanley found convincing.
That was just as well…because if they had done so, the movie would have been badly dated by the Voyager missions, which showed Saturn’s rings to be far more implausible than anyone had ever imagined.
I have seen enough instances where Nature imitates art, so I’m going to keep my fingers crossed on what Cassini discovers at Iapetus.
I want to thank everyone associated with this mission and the overall Cassini-Huygens project. It may lack the glamour of manned spaceflight, but science projects are tremendously important for our understanding of the Solar System. And who knows, one day our survival on Earth might depend on what we discover out there…
This is Arthur Clarke, wishing you a successful flyby.
Yeah, I should have warned you yesterday. This isn’t meant as a cruel joke — honestly. NASA has the details:
As August draws to an end, watchers of the night sky will be in for a treat. In the early morning hours of August 28, sky watchers across much of the world can look on as the Moon crosses in to the shadow of the Earth, becoming completely immersed for one-hour and 30 minutes, a period of time much longer than most typical lunar eclipses. In fact, this eclipse will be the deepest and longest in 7 years.
The event begins[began] 54 minutes past midnight PDT (3:54 a.m. EDT) on August 28. At first, there is little change. The outskirts of Earth’s shadow are as pale as the Moon itself; an onlooker might not even realize anything is happening. But as the Moon penetrates deeper in to the Earth’s shadow, a startling metamorphosis occurs. Around 2:52 a.m. PDT (5:52 a.m. EDT) the color of the Moon changes from moondust-gray to sunset-red. This is totality, and it lasts for almost 90 minutes.
With the Sun blocked, you might expect utter darkness, but instead the ground at your feet appears to be aglow. Why? Look back up at Earth. The rim of the planet seems to be on fire. Around the Earth’s circumference you will witness every sunrise and sunset in the world—all at once. This incredible, colorful light beams into the heart of Earth’s shadow, transforming the Moon into a landscape of copper moondust and golden hills. The eclipse will be visible from Australia, parts of Asia and most of the Americas, but not from Africa or Europe. The view is different from each location on the planet. Here in the United States, Pacific observers are favored. For them the entire eclipse will unfold high in the post-midnight sky. However, on the East Coast, totality will be cut off early by sunrise.
It didn’t disappoint. As viewed from Katana, ON (link):
Without a doubt, Google Earth has put the functional utility of satellite imaging at the fingertips of millions, rekindling for many the shear wonder of what satellites can do to improve our lives.
Now Google’s virtual "satellites" (which aren’t really satellites, of course, but rather "the superimposition of images obtained from satellite imagery, aerial photography and GIS3D") are doing what no single satellite has yet been designed to do: they’re turning their gaze from the Earth to the Heavens with today’s release of Google Sky:
With Sky, users can now float through the skies via Google Earth. This easy-to-use tool enables all Earth users to view and navigate through 100 million individual stars and 200 million galaxies. High resolution imagery and informative overlays create a unique playground for visualizing and learning about space.
To access Sky, users need only click "Switch to Sky" from the "view" drop-down menu in Google Earth, or click the Sky button on the Google Earth toolbar. The interface and navigation are similar to that of standard Google Earth steering, including dragging, zooming, search, "My Places," and layer selection….
"Never before has a roadmap of the entire sky been made so readily available. Anyone interested in exploring the wonders of our universe can quickly see where the stunning objects photographed by Hubble actually dwell in the heavens. Sky in Google Earth will foster and initiate new understanding of the universe by bringing it to everyone’s home computer," said Dr. Carol Christian of STScI, who co-led the organization’s Sky team with Dr. Alberto Conti.
Google Sky features seven layers, including Hubble Space Telescope Imagery, Constellations, the Moon and Planets, a "Users Guide to Galaxies" and a "Life of a Star" layer, as well "The Backyard Astronomer," which "is useful for the amateur astronomer who may benefit from a comprehensive, organized way to reference fragments of the night sky."
"The Sky imagery was stitched together from more than one million photographs from scientific and academic sources, including the Sloan Digital Sky Survey, the Palomar Observatory at the California Institute of Technology and the NASA-financed Hubble," according to the New York Times.
Astronomy buffs throughout the Northern Hemisphere have been staying up late recently to view the Perseids meteor shower, which peaked on August 12th during the new moon.
Spaceweather.com has a fine collection of photographs of the meteor shower. (The photo above is taken from their collection.)
At its peak Sunday night, the Perseids awed observers with up to 80 meteors per minute visible in a clear sky.
We’ve been fans of the Perseids since the early 1990s, when the comet Swift-Tuttle — the parent body of the Perseid meteor cloud — made its closest pass to earth since Abe Lincoln was president. The proximity of Swift-Tuttle meant that the Perseids were particularly spectacular during our salad days of 1993.
None of us, however, are likely to be around for the comet’s next perihelion passage in August of 2126 (when it may be as bright as Hale-Bopp), but until then the Perseids’ peak — usually August 12th — remains one of the best nights of the year to set up an astronomy date.
1. Perseid meteoroids (which is what they’re called while in space) are fast. They enter Earth’s atmosphere (and are then called meteors) at roughly 133,200 mph (60 kilometers per second) relative to the planet. Most are the size of sand grains; a few are as big as peas or marbles. Almost none hit the ground, but if one does, it’s called a meteorite.
2. Comet Swift-Tuttle, whose debris creates the Perseids, is the largest object known to make repeated passes near Earth. Its nucleus is about 6 miles (9.7 kilometers) across, roughly equal to the object that wiped out the dinosaurs.
3. Back in the early 1990s, astronomer Brian Marsden calculated that Swift-Tuttle might actually hit Earth on a future pass. More observations quickly eliminated all possibility of a collision. Marsden found, however, that the comet and Earth might experience a cosmic near miss (about a million miles) in 3044.
Check out the complete article (and 7 other interesting facts) here.
We’ve seen meteors in New Jersey before, but this is something else. This crashed through a roof in Bayonne and people thought is was space junk, or part of a commercial jet.
BAYONNE, N.J. (AP) — It didn’t take a rocket scientist to solve the mystery of what it was that fell through the roof of a Bayonne home Tuesday, though some had wondered if it was part of a space craft.
Federal Aviation Administration spokesman Jim Peters on Wednesday said the mystery metal was part of a commercial woodchipper.
For most of a day, the FAA, New Jersey Transit officials and others were scratching their heads about what the hunk of gray metal may have been.
The man who lives in the house was watching television Tuesday when he heard a crash and saw a cloud of dust. In the next room, he found a hunk of gray metal, 3{ inches by 5 inches, with two hexagonal holes in it.
Experts said it was manmade, but couldn’t identify it.
New Jersey Transit has railroad tracks about 100 feet from the house, but spokesman Dan Stessel said the object isn’t something that would have flown off a train.
FAA officials said it wasn’t a part that would have fallen from a plane headed into or out of nearby Newark Liberty International Airport.
A NASA scientist said it did not appear to be part of a spacecraft.
Peters said that when an FAA inspector took the piece back to his office Tuesday afternoon to work on the mystery, a colleague recognized the piece.
The same part from a different machine had caused similar confusion — though it did not get any publicity — last year. Peters said the inspector could not remember where in New Jersey the other one fell.
The part came from the grinder of a woodchipper. Peters said the piece moves very fast and, apparently, can launch into the air if something goes wrong. "Maybe we can use it as a new weapon,” he joked.
