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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The comet and The Pleiades

Photo: Comet C/2014 Q2 by Dave Watkins

Comet C/2014 Q2 (Lovejoy) with The Pleiades by Dave Watkins

Club member Dave Watkins was inspired to brave a cold night in January to try and capture a photo of Comet Lovejoy (2014 Q2/Lovejoy) but, “It was just too cold to set up the Celestron and/or mount!” Using his camera gear mounted on a tripod and employing modern techniques, Dave captured a beautiful image of the comet as it passed close to the Pleiades star cluster (M45) the night of January 14. (Click the image to see full-size.)

He reports he “really had to play with the ISO and shutter speed because of all the light pollution.”

Technical details: Canon 5D Mark II body, Canon 70-200mm lens @ 70mm, f2.8, ISO400, 5-second exposures, 245 light images, 29 dark images, 29 flat files, master bias file, calibrated, aligned, integrated, and processed in PixInsight with some help from Photoshop.

Image: Comet finder chart for January 2015 - Credit: FreeStarCharts.com

Credit: FreeStarCharts.com

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Hubble revisits iconic “Pillars of Creation” image

Photo: Iconic "Pillars of Creation" reimaged. Credit: NASA, ESA/Hubble and the Hubble Heritage Team

New view of the Pillars of Creation — Visible Light. Click to Enlarge.

The NASA/ESA Hubble Space Telescope has captured many breathtaking images of the Universe, but one snapshot stands out from the rest: the Eagle Nebula’s Pillars of Creation. In 1995 Hubble’s iconic image revealed never-before-seen details in the giant columns and now the telescope is kickstarting its 25th year in orbit with an even clearer, and more stunning, image of these beautiful structures.

The three impressive towers of gas and dust captured in this image are part of the Eagle Nebula, otherwise known as Messier 16. Although such features are not uncommon in star-forming regions, the Messier 16 structures are by far the most photogenic and evocative ever captured. The Hubble image of the pillars taken in 1995 is so popular that it has appeared in film and television, on tee-shirts and pillows, and even on postage stamps.

Now Hubble has revisited the famous pillars, capturing the multi-colored glow of gas clouds, wispy tendrils of dark cosmic dust, and the rust-colored elephants’ trunks with the newer Wide Field Camera 3, installed in 2009. The visible-light image builds on one of the most iconic astronomy images ever taken and provides astronomers with an even sharper and wider view.

In addition to this new visible-light image, Hubble has also produced a bonus image. This image is taken in infrared light, which penetrates much of the obscuring dust and gas and unveils a more unfamiliar view of the pillars, transforming them into wispy silhouettes set against a background peppered with stars. Here newborn stars, hidden in the visible-light view, can be seen forming within the pillars themselves.

Photos: The Pillars of Creation, New and Old. Credit: NASA, ESA/Hubble and the Hubble Heritage Team

The Pillars of Creation – New and Old

Although the original image was dubbed the “Pillars of Creation”, this new image hints that they are also pillars of destruction. The dust and gas in these pillars is seared by intense radiation from the young stars forming within them, and eroded by strong winds from massive nearby stars. The ghostly bluish haze around the dense edges of the pillars in the visible-light view is material that is being heated by bright young stars and evaporating away.

With these new images come better contrast and clearer views of the region. Astronomers can use these new images to study how the physical structure of the pillars is changing over time. The infrared image shows that the reason the pillars exist is because the very ends of them are dense, and they shadow the gas below them, creating the long, pillar-like structures. The gas in between the pillars has long since been blown away by the winds from a nearby star cluster.

At the top edge of the left-hand pillar, a gaseous fragment has been heated up and is flying away from the structure, highlighting the violent nature of star-forming regions.

These massive stars may be slowly destroying the pillars but they are also the reason Hubble sees the structures at all. They radiate enough ultraviolet light to illuminate the area and make the clouds of oxygen, hydrogen and sulphur glow.

Although structures like these exist throughout the Universe, the Pillars of Creation — at a distance of 6,500 light-years away — provide the best, and most dramatic, example. Now, these images have allowed us to see them more clearly than ever, proving that at 25 years of age, Hubble is still going strong.

This image and the associated results were presented today at the 225th meeting of the American Astronomical Society in Seattle, Washington, USA.

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November 10: Meeting, Elections, and Program

The Cuyahoga Astronomical Association will hold its final general meeting and program for the year on Monday, November 10, 7:30 PM at the Rocky River Nature Center. In addition to regular club business, the biennial nomination and election of club officers and at-large board members will take place.

“Archaeo-astronomy” will be the topic of the evening’s astronomy presentation. Speaker Ed Alderman will describe how early man viewed the skies and measured the motions of the stars and planets.

Attendance by guests is welcome but participation in club business and elections is restricted to current members of the club.

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A View of Orion

IMG_1138.JPG

This image of the Orion Nebula (M42) was recorded from the CAA Letha House observing site. Member Christopher Christie wrote that he made the image “during the September new moon with a 65mm refractor and DSLR. As for all the details, I forget most. But it was a Canon T3, 1600 ISO with my AT65EDQ, about 3 hours of subs, stacked and processed in Pixinsight.”

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The Beautiful “Elephant Trunk”

IC 1396 - The "Elephant Trunk" Nebula in Cepheus, by Joe Golias

IC 1396 – The “Elephant Trunk” Nebula in Cepheus

by Joe Golias

We were fortunate enough to have clear skies this past weekend and I managed to do some narrowband imaging from my back yard in Granger, Ohio. I’d like to share with everyone one of my latest CCD images taken of the Elephant trunk nebula IC 1396 located in the constellation of Cepheus. I often wonder why I bother traveling great distances to dark sky sites like Texas and Florida when I can get results like this from my back yard in Ohio!

Imaging details: Telescope: Takahashi TOA 150 Refractor. Camera: SBIG ST8300M with self-guiding filter wheel. Mount: Losmandy: G-11. Exposure times in narrowband: 4 hours SII filter with 20-min. sub exposures, 4 hours OIII filter with 20-min. sub exposures, 4 hours HA filter with 20-min. sub exposures. Location: Granger, Ohio. Processed in MaxIm DL, Images Plus, Pixinsight, and Photoshop. Final RGB combination was converted using the Hubble color palette, HST.

CAA Member Joe Golias is (obviously) an expert astro-imager and is owner of Astrozap, a Cleveland-area company that produces astronomy accessories.

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