First Public Star Party of 2015

Photo: Venus & Gemini Setting. Photo by James Guilford.

Venus and Gemini Setting over the lake in Letha House Park – Photo by James Guilford.

Saturday night, May 23, the Cuyahoga Astronomical Association (CAA) held our first Public Star Party for 2015. The event took place at the club’s observatory situated on the grounds of the Medina County Park System’s Letha House Park in Spencer, Ohio. Members of the public were generally enthusiastic, excitedly moving between telescopes. The sky was beautifully clear and allowed excellent views of the Moon, Jupiter, Saturn, Venus, the Hercules Star Cluster (M13), M81 & M82, and other astronomical wonders.

CAA President William Murmann wrote, “Thanks to everyone who attended and who brought scopes to help with the program!

“The park staff said we had about 50 guests join us, including families with children.  We had clear skies all day, but some high, thin wispy stuff moved in during the evening, although we had good observing.

“It was nice to see to James Guilford, Steve Spears, Chris Christe, Chris Burke, Paul Leopold, Suzie Dills, Trevor Braun, Bob Wiersma, Jay Reynolds, Rich Rinehart, Bill & Carol Lee, Tim Campbell and Mary Ann, Steve & Gail Korylak, Rich & Nancy Whisler, Dave & Jan Heideloff, Carl Kudrna, Larry Smith — and new member Anita Kazarian, who joined us.  Sorry if I missed anyone.

“Noteworthy for the evening–Steve Korylak spotted Comet Lovejoy with his scope.

“It was a nice program and a nice get together for members.  Thanks again.”

……………..

Simulated View of Moon and Acubens

Simulated View of Moon and Acubens

Among the objects the public viewed in beautiful detail was Earth’s Moon. Early in the evening not only could observers see the brightly-lit portion of the Moon but also the Earth-lit shadowed portion of the disk. Adding to the scene was a beautiful speck of a star near the horn of the Moon: Acubens, a star in constellation Cancer.

 

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Lopsided supernova reveals secrets of those enormous explosions

Photo: Remnant Supernova 1987A

The still-unravelling remains of supernova 1987A are shown in this image taken by the Hubble Space Telescope. The bright ring consists of material ejected from the dying star before it detonated. The ring is being lit by the explosion’s shock wave. Credit: ESA/Hubble, NASA

Written by Ker Than, Caltech News

New observations of a recently exploded star are confirming supercomputer model predictions made at Caltech that the deaths of stellar giants are lopsided affairs in which debris and the stars’ cores hurtle off in opposite directions.

While observing the remnant of supernova (SN) 1987A, NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, recently detected the unique energy signature of titanium-44, a radioactive version of titanium that is produced during the early stages of a particular type of star explosion, called a Type II, or core-collapse supernova.

“Titanium-44 is unstable. When it decays and turns into calcium, it emits gamma rays at a specific energy, which NuSTAR can detect,” says Fiona Harrison, the Benjamin M. Rosen Professor of Physics at Caltech, and NuSTAR’s principal investigator.

By analyzing direction-dependent frequency changes—or Doppler shifts—of energy from titanium-44, Harrison and her team discovered that most of the material is moving away from NuSTAR. The finding, detailed in the May 8 issue of the journal Science, is the best proof yet that the mechanism that triggers Type II supernovae is inherently lopsided.

NuSTAR recently created detailed titanium-44 maps of another supernova remnant, called Cassiopeia A, and there too it found signs of an asymmetrical explosion, although the evidence in this case is not as definitive as with 1987A.

Supernova 1987A was first detected in 1987, when light from the explosion of a blue supergiant star located 168,000 light-years away reached Earth. SN 1987A was an important event for astronomers. Not only was it the closest supernova to be detected in hundreds of years, it marked the first time that neutrinos had been detected from an astronomical source other than our sun.

These nearly massless subatomic particles had been predicted to be produced in large quantities during Type II explosions, so their detection during 1987A supported some of the fundamental theories about the inner workings of supernovae.

With the latest NuSTAR observations, 1987A is once again proving to be a useful natural laboratory for studying the mysteries of stellar death. For many years, supercomputer simulations performed at Caltech and elsewhere predicted that the cores of pending Type II supernovae change shape just before exploding, transforming from a perfectly symmetric sphere into a wobbly mass made up of turbulent plumes of extremely hot gas. In fact, models that assumed a perfectly spherical core just fizzled out.

“If you make everything just spherical, the core doesn’t explode. It turns out you need asymmetries to make the star explode,” Harrison says.

According to the simulations, the shape change is driven by turbulence generated by neutrinos that are absorbed within the core. “This turbulence helps push out a powerful shock wave and launch the explosion,” says Christian Ott, a professor of theoretical physics at Caltech who was not involved in the NuSTAR observations.

Ott’s team uses supercomputers to run three-dimensional simulations of core-collapse supernovae. Each simulation generates hundreds of terabytes of results—for comparison, the entire print collection of the U.S. Library of Congress is equal to about 10 terabytes—but represents only a few tenths of a second during a supernova explosion.

A better understanding of the asymmetrical nature of Type II supernovae, Ott says, could help solve one of the biggest mysteries surrounding stellar deaths: why some supernovae collapse into neutron stars and others into a black hole to form a space-time singularity. It could be that the high degree of asymmetry in some supernovae produces a dual effect: the star explodes in one direction, while the remainder of the star continues to collapse in all other directions.
“In this way, an explosion could happen, but eventually leave behind a black hole and not a neutron star,” Ott says.

The NuSTAR findings also increase the chances that Advanced LIGO — the upgraded version of the Laser Interferometer Gravitational-wave Observatory, which will begin to take data later this year — will be successful in detecting gravitational waves from supernovae. Gravitational waves are ripples that propagate through the fabric of space-time. According to theory, Type II supernovae should emit gravitational waves, but only if the explosions are asymmetrical.

Harrison and Ott have plans to combine the observational and theoretical studies of supernova that until now have been occurring along parallel tracks at Caltech, using the NuSTAR observations to refine supercomputer simulations of supernova explosions.

“The two of us are going to work together to try to get the models to more accurately predict what we’re seeing in 1987A and Cassiopeia A,” Harrison says.

Additional Caltech coauthors of the paper, entitled “44Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion,” are Hiromasa Miyasaka, Brian Grefenstette, Kristin Madsen, Peter Mao, and Vikram Rana. The research was supported by funding from NASA, the French National Center for Space Studies (CNES), the Japan Society for the Promotion of Science, and the Technical University of Denmark.

This article also references the paper “Magnetorotational Core-collapse Supernovae in Three Dimensions,” which appeared in the April 20, 2014, issue of Astrophysical Journal Letters.

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Spacecraft returns early images hinting surface features on Pluto, possible polar cap

Pluto and Charon. Credits: NASA/JHU-APL/SwRI

Click for Full-Size View. Credits: NASA/JHU-APL/SwRI

For the first time, images from NASA’s New Horizons spacecraft are revealing bright and dark regions on the surface of faraway Pluto – the primary target of the New Horizons close flyby in mid-July.

The images were captured in early to mid-April from within 70 million miles (113 million kilometers), using the telescopic Long-Range Reconnaissance Imager (LORRI) camera on New Horizons. A technique called image deconvolution sharpens the raw, unprocessed images beamed back to Earth. New Horizons scientists interpreted the data to reveal the dwarf planet has broad surface markings – some bright, some dark – including a bright area at one pole that may be a polar cap.

“As we approach the Pluto system we are starting to see intriguing features such as a bright region near Pluto’s visible pole, starting the great scientific adventure to understand this enigmatic celestial object,” says John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. “As we get closer, the excitement is building in our quest to unravel the mysteries of Pluto using data from New Horizons.”

Also captured in the images is Pluto’s largest moon, Charon, rotating in its 6.4-day long orbit. The exposure times used to create this image set – a tenth of a second – were too short for the camera to detect Pluto’s four much smaller and fainter moons.

Since it was discovered in 1930, Pluto has remained an enigma. It orbits our sun more than 3 billion miles (about 5 billion kilometers) from Earth, and researchers have struggled to discern any details about its surface. These latest New Horizons images allow the mission science team to detect clear differences in brightness across Pluto’s surface as it rotates.

“After traveling more than nine years through space, it’s stunning to see Pluto, literally a dot of light as seen from Earth, becoming a real place right before our eyes,” said Alan Stern, New Horizons principal investigator at Southwest Research Institute in Boulder, Colorado. “These incredible images are the first in which we can begin to see detail on Pluto, and they are already showing us that Pluto has a complex surface.”

The images the spacecraft returns will dramatically improve as New Horizons speeds closer to its July rendezvous with Pluto.

“We can only imagine what surprises will be revealed when New Horizons passes approximately 7,800 miles (12,500 kilometers) above Pluto’s surface this summer,” said Hal Weaver, the mission’s project scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

From a NASA news release.

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Major observatory donated to RASC

Photo: David Dunlap Observatory

David Dunlap Observatory

Richmond Hill, ON – In what astronomers might describe as “stellar news,” Corsica Development Inc. is donating the David Dunlap Observatory (DDO) to the facility’s long-time stewards – the Royal Astronomical Society of Canada, Toronto Centre. The observatory is 80 years old this year. It houses what is still the largest optical telescope in the country with a mirror measuring 74 inches (1.9meters) across.

The decision was made in 2012 by Corsica to transfer the Administration Building and Dome to an agency that would honor the spirit of the Observatory and ensure its long-term viability. Members of the RASC Toronto Centre have been managing and operating the David Dunlap Observatory for the last six years and are the resident experts.

Corsica, which purchased the 190 acre Observatory property from the University of Toronto in 2008, is also donating nearly 100 acres of the land to the Town of Richmond Hill.

RASC Toronto Centre has been involved in public outreach programs at the Dunlap Observatory since it first opened in 1935. The registered charity took on full responsibility for the Observatory and Administration building in 2009, including maintaining and operating the largest optical telescope in Canada. “We’re honored by this incredibly generous gift,” says Paul Mortfield, President of RASC Toronto Centre. “Fred DeGasperis was very supportive of our work at the DDO and our commitment as stewards of the Observatory and telescope. We will always be grateful for the confidence he showed in us.”

The historic buildings will continue to be a centre for education and science literacy for the community.

For the last six years RASC Toronto Centre member volunteers have managed the facility and provided hundreds of award-winning educational and outreach programs to York Region families and students. They’ve done so without the use of local tax dollars.

Centre members say they’re looking forward to working collaboratively with the town on new programs and projects that will continue to benefit town residents.

Please see the announcement on www.theDDO.ca for more information.

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Crescent Moon shows off some craters

  

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Tracing the Milky Way’s magnetic field

Image: Polarized Emission from Milky Way Dust. Credit: ESA and the Planck Collaboration

Polarized Emission from Milky Way Dust

The interaction between interstellar dust in the Milky Way and the structure of our Galaxy’s magnetic field, as detected by the European Space Agency’s Planck satellite over the entire sky.

Planck scanned the sky to detect the most ancient light in the history of the Universe – the cosmic microwave background. It also detected significant foreground emission from diffuse material in our galaxy which, although a nuisance for cosmological studies, is extremely important for studying the birth of stars and other phenomena in the Milky Way.

Among the foreground sources at the wavelengths probed by Planck is cosmic dust, a minor but crucial component of the interstellar medium that pervades the galaxy. Mainly gas, it is the raw material for stars to form.

Interstellar clouds of gas and dust are also threaded by the galaxy’s magnetic field, and dust grains tend to align their longest axis at right angles to the direction of the field. As a result, the light emitted by dust grains is partly ‘polarized’ – it vibrates in a preferred direction – and, as such, could be caught by the polarization-sensitive detectors on Planck.

Scientists in the Planck collaboration are using the polarized emission of interstellar dust to reconstruct the galaxy’s magnetic field and study its role in the build-up of structure in the Milky Way, leading to star formation.

In this image, the color scale represents the total intensity of dust emission, revealing the structure of interstellar clouds in the Milky Way. The texture is based on measurements of the direction of the polarized light emitted by the dust, which in turn indicates the orientation of the magnetic field.

Credit: ESA and the Planck Collaboration

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Close encounter with Jupiter

Photo: Jupiter with moons, by David Watkins.

Near opposition: Jupiter along with Europa, Ganymede, and Io. On a frigid February night, CAA member David Watkins used his 5X Powermate on his 8-inch Celestron to view the Jupiter atmosphere as he had never seen it before! From Cuyahoga Falls, Ohio.

by Dr. Tony Phillips

February 6, 2015 — Every 13 months, Earth and Jupiter have a close encounter. Astronomers call it an “opposition” because Jupiter is opposite the Sun in the sky. Our solar system’s largest gas planet rises in the east at sunset, and soars overhead at midnight, shining brighter than any star in the night sky.

This year’s opposition of Jupiter occurs on Feb. 6. It isn’t an ordinary close encounter with Earth (approximately 640 million kilometers), but in Feb. 2015, Jupiter is edge on to the Sun.

Jupiter’s opposition on Feb. 6 coincides almost perfectly with its equinox on Feb. 5 when the Sun crosses Jupiter’s equatorial plane. It is an edge-on apparition of the giant planet that sets the stage for a remarkable series of events. For the next couple of months, backyard sky watchers can see the moons of Jupiter executing a complex series of mutual eclipses and transits.

The eclipses have already started. On Jan. 24, for example, three of Jupiter’s moon’s, Io, Europa, and Callisto, cast their inky-black shadows on Jupiter’s swirling cloudtops. The “triple shadow transit” happened while Jupiter was high in the sky over North America, and many backyard astronomers watched the event.

As Earth’s crosses the plane of Jupiter’s equator in the weeks and months ahead, there will be many mutual events. For instance, on Feb. 5, volcanic Io will cast its shadow on Mercury-sized Ganymede, Jupiter’s largest moon. On Feb. 7, icy Europa, home to what may be the solar system’s largest underground ocean, will cast its shadow on Io. Events like these will continue, off and on, until July 2015.

During the last edge-on apparition in 2009, some observers managed to obtain the first resolved time-lapse videos of mutual phenomena. Experienced amateur astronomers recorded satellites ducking in and out of one another’s shadows, moons in partial and total eclipse, and multiple shadows playing across the face of Jupiter. Backyard telescopes have come a long way in the past six years, so even better movies can be expected this time.

You don’t have to be an experienced astronomer to experience Jupiter’s opposition. Anyone can see the bright planet rising in the east at sunset. It outshines by far anything else in its patch of sky. Point a small telescope at the bright light and, voila!–there are Jupiter’s cloud belts and storms, and the pinprick lights of the Galilean satellites circling the gas giant below.

Try it; 640 million kilometers won’t seem so far away at all.

Credit: Science@NASA

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