Category: Astrophotos

While cruising around Saturn in early October, Cassini captured a series of images that have been composed into the largest, most detailed, global natural color view of Saturn and its rings ever made.

This grand mosaic consists of 126 images acquired in a tile-like fashion, covering one end of Saturn’s rings to the other and the entire planet in between. The images were taken over the course of 2 hours on October 6, 2004, while Cassini was approximately 6.3 million kilometers (3.9 million miles) from Saturn. Since the view seen by Cassini during this time changed very little, no re-projection or alteration of any of the images was necessary.

Three images (red, green and blue) were taken at each of 42 locations, or ?footprints?, across the planet. The full color footprints were mosaicked together to produce a final product that is 8,888 pixels across and 4,544 pixels tall.

The smallest features seen here are 38 kilometers (24 miles) across. Many of Saturn’s splendid features noted previously in single frames taken by Cassini are visible in this one detailed, all-encompassing view: Subtle color variations across the rings, the thread-like F ring, ring shadows cast against the blue northern hemisphere, the planet?s shadow making its way across the rings to the left, blue-grey storms in Saturn’s southern hemisphere to the right and tiny Mimas and even smaller Janus (both faintly visible at lower left).

The Sun-Saturn-Cassini, or phase, angle at the time was 72 degrees; hence, the partial illumination of Saturn in this portrait. Later in the mission, when the spacecraft?s trajectory takes it far from Saturn and also into the direction of the Sun, Cassini will be able to look back and view Saturn and its rings in a more fully-illuminated geometry.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: NASA/JPL/SSI News Release

Amateur photographer Paul F. Campbell took this picture of Jupiter from just outside his home in Washington, PA. Paul used a Meade ETX autostar in polar mode only, which has been supercharged by Dr. Clay Sherrod. The camera that I use is a Sac 7 CCD run by Astrovideo. The photo started out as a 1 minute video, with frames taken at 1/50 second. Paul then processed the video in registax 3 and then cleaned up the final photo in Adobe Photoshop. If you’re an amateur astrophotographer, visit the Universe Today forum and post your pictures, we might feature it in the newsletter.

Amateur photographer John Chumack took this picture of Spiral Galaxy NGC-253, which is located in the constellation of Sculptor. The telescope was a Takahashi Epsilon 250mm and ST8XE CCD camera, on a Software Bisque Paramount ME, taken on Mount Joy, New Mexico, New Mexico Skies Resort. John operated the telescope remotely from Dayton, Ohio using Arnie Rosner’s Rent-A-Scope setup. John has been imaging the sky for 2 decades, and has an amazing collection of pictures at his website: Galactic Images. If you’re an amateur astrophotographer, visit the Universe Today forum and post your pictures, we might feature it in the newsletter.

The Hubble Space Telescope’s latest image of the star V838 Monocerotis (V838 Mon) reveals dramatic changes in the illumination of surrounding dusty cloud structures. The effect, called a light echo, has been unveiling never-before-seen dust patterns ever since the star suddenly brightened for several weeks in early 2002.

The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a pulse of light three years ago, somewhat similar to setting off a flashbulb in a darkened room. The dust surrounding V838 Mon may have been ejected from the star during a previous explosion, similar to the 2002 event.

The echoing of light through space is similar to the echoing of sound through air. As light from the stellar explosion continues to propagate outwards, different parts of the surrounding dust are illuminated, just as a sound echo bounces off of objects near the source, and later, objects further from the source. Eventually, when light from the back side of the nebula begins to arrive, the light echo will give the illusion of contracting, and finally it will disappear.

V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy. The Hubble telescope has imaged V838 Mon and its light echo several times since the star’s outburst. Each time Hubble observes the event, different thin sections of the dust are seen as the pulse of illumination continues to expand away from the star at the speed of light, producing a constantly changing appearance. During the outburst event whose light reached Earth in 2002, the normally faint star suddenly brightened, becoming 600,000 times more luminous than our Sun.

The new image of V838 Mon, taken with Hubble’s Advanced Camera for Surveys, was prepared from images obtained through filters that isolate blue, green, and infrared light. These images have been combined to produce a full-color picture that approximates the true colors of the light echo and the very red star near the center.

Original Source: Hubble News Release

One of the largest Hubble Space Telescope images ever made of a complete galaxy is being unveiled today at the American Astronomical Society meeting in San Diego, Calif.

The Hubble telescope captured a display of starlight, glowing gas, and silhouetted dark clouds of interstellar dust in this 4-foot-by-8-foot image of the barred spiral galaxy NGC 1300. NGC 1300 is considered to be prototypical of barred spiral galaxies. Barred spirals differ from normal spiral galaxies in that the arms of the galaxy do not spiral all the way into the center, but are connected to the two ends of a straight bar of stars containing the nucleus at its center.

At Hubble’s resolution, a myriad of fine details, some of which have never before been seen, is seen throughout the galaxy’s arms, disk, bulge, and nucleus. Blue and red supergiant stars, star clusters, and star-forming regions are well resolved across the spiral arms, and dust lanes trace out fine structures in the disk and bar. Numerous more distant galaxies are visible in the background, and are seen even through the densest regions of NGC 1300.

In the core of the larger spiral structure of NGC 1300, the nucleus shows its own extraordinary and distinct “grand-design” spiral structure that is about 3,300 light-years (1 kiloparsec) long. Only galaxies with large-scale bars appear to have these grand-design inner disks ? a spiral within a spiral. Models suggest that the gas in a bar can be funneled inwards, and then spiral into the center through the grand-design disk, where it can potentially fuel a central black hole. NGC 1300 is not known to have an active nucleus, however, indicating either that there is no black hole, or that it is not accreting matter.

The image was constructed from exposures taken in September 2004 by the Advanced Camera for Surveys onboard Hubble in four filters. Starlight and dust are seen in blue, visible, and infrared light. Bright star clusters are highlighted in red by their associated emission from glowing hydrogen gas. Due to the galaxy’s large size, two adjacent pointings of the telescope were necessary to cover the extent of the spiral arms. The galaxy lies roughly 69 million light-years away (21 megaparsecs) in the direction of the constellation Eridanus.

Original Source: Hubble News Release

This close-up of the lit side of Saturn’s outer B ring and the Cassini Division looks something like a phonograph record. There are subtle, wavelike patterns, hundreds of narrow features resembling a record’s ‘grooves’ and a noticeable abrupt change in overall brightness beyond the dark gap near the right. To the left of the gap is the outer B ring with its sharp edge maintained by a strong gravitational resonance with the moon Mimas. To the right of the Huygens Gap are the plateau-like bands of the Cassini Division. The narrow ringlet within the gap is called the Huygens ringlet.

The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 29, 2004, at a distance of about 819,000 (509,000 miles) from Saturn. The image scale is 4.5 kilometers (2.8 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Twenty-five years ago, on September 28, 1979, the Canada-France-Hawaii Telescope (CFHT) was inaugurated on top of Mauna-Kea, a 4,200-meter high dormant volcano on the island of Hawai?i.

From the photographic emulsion of the first light to today’s 340 Mega-Pixel digital camera, CHFT?s instruments are cutting edge; its camera is the largest ever built in operation on a telescope. With high-resolution or multi-object spectroscopy, adaptive optics and polarimetry, CFHT has played an important role for a quarter of a century in the development of astronomy, thanks to the support of its member agencies in Canada, France and the State of Hawaii.

Once one of the large telescopes in the world, with a mirror 3.6-m in diameter (a ‘small’ telescope by today’s standards), CFHT continues to serve the astronomical community with stunning images and groundbreaking discoveries, from the small bodies of our solar system to remote galaxies; this has been possible due to a state-of-the-art instrument complement well-suited to the relatively modest size of its mirror and the extraordinary quality of its site.

The spectacular image released today is one of the best ground-based images ever made combining wide field and high resolution. It is the result of tens of hours of telescope time spent on a single 1-degree by 1-degree field for the CFHT Legacy Survey (CFHTLS), one of CFHT’s most ambitious scientific endeavors so far. Canada and France are devoting 500 nights of telescope time to the CFHTLS over 5 years to tackle important questions in today’s astronomy.

While there are still years to go to complete the CFHTLS, this image comes as a spectacular milestone to celebrate 25 years of excellence… and counting!

Original Source: CFHT News Release

Saturn’s ring shadows appear wrapped in a harmonious symphony with the planet in this color view from the Cassini spacecraft.

Saturn and its rings would nearly fill the space between Earth and the Moon. Yet, despite their great breadth, the rings are a few meters thick and, in some places, very translucent. This image shows a view through the C ring, which is closest to Saturn, and through the Cassini division, the 4,800-kilometer-wide gap (2,980-miles) that arcs across the top of the image and separates the optically thick B ring from the A ring. The part of the atmosphere seen through the gap appears darker and more bluish due to scattering at blue wavelengths by the cloud-free upper atmosphere.

The different colors in Saturn’s atmosphere are due to particles whose composition is yet to be determined. This image was obtained with the Cassini spacecraft narrow angle camera on July 30, 2004, at a distance of 7.6 million kilometers (4.7 million miles) from Saturn.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For images and information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. Images are also available at the Cassini imaging team home page, http://ciclops.org.

Original Source: NASA/JPL News Release

This photo of Hurricane Frances was taken by Astronaut Mike Fincke aboard the International Space Station as he flew 230 statute miles above the storm at about 9 a.m. CDT Friday, Aug. 27, 2004. At the time, Frances was located 820 miles east of the Lesser Antilles in the Atlantic Ocean, moving west-northwest at 10 miles per hour, with maximum sustained winds of 105 miles per hour. Fincke, the NASA ISS Science Officer and Flight Engineer, and Expedition 9 Commander Gennady Padalka are in the fifth month of a six-month flight aboard the Station.

Original Source: NASA News Release

Known to amateur astronomers as the ‘Little Ghost Nebula’, because it appears as a small, ghostly cloud surrounding a faint dying star, NGC 6369 lies in the direction of the constellation Ophiuchus.

The NASA/ESA Hubble Space Telescope has took this image of the planetary nebula NGC 6369, at a distance estimated to be between about 2000 and 5000 light-years from Earth.

When a star with a mass similar to that of our own Sun nears the end of its lifetime, it expands in size to become a ‘red giant’. The red-giant stage ends when the star expels its outer layers into space, producing a faintly glowing nebula.

Astronomers call such an object a planetary nebula, because its round shape resembles that of a planet when viewed with a small telescope.

The Hubble photograph of NGC 6369, captured with the Wide Field Planetary Camera 2 (WFPC2) in 2002, reveals remarkable details of the ejection process that are not visible from ground-based telescopes because of the blurring produced by the Earth’s atmosphere.

The remnant stellar core in the centre is now sending out a flood of ultraviolet (UV) light into the surrounding gas. The prominent blue-green ring, nearly a light-year in diameter, marks the location where the energetic UV light has stripped electrons off of atoms in the gas. This process is called ionisation.

In the redder gas at larger distances from the star, where the UV light is less intense, the ioniszation process is less advanced. Even farther outside the main body of the nebula, one can see fainter wisps of gas that were lost from the star at the beginning of the ejection process.

This colour image has been produced by combining WFPC2 pictures taken through filters that isolate light emitted by three different chemical elements with different degrees of ionisation.

The doughnut-shaped blue-green ring represents light from ionised oxygen atoms that have lost two electrons (blue) and from hydrogen atoms that have lost their single electrons (green). Red marks emission from nitrogen atoms that have lost only one electron. Our own Sun may eject a similar nebula, but not for another 5000 million years.

The gas will expand away from the star at about 15 miles per second, dissipating into interstellar space after some 10 000 years. After that, the remnant stellar member in the centre will gradually cool off for millions of years as a tiny white dwarf star, and eventually wink out.

Original Source: ESA News Release