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Category Archives: 03. Light and telescopes: extending our senses

The November 11, 2013, Astronomy Picture of the Day shows the total solar eclipse of November 3, as covered by several different solar observatories.


Credit and copyright: D. Seaton (ROB), A. Davis & J. M. Pasachoff (Williams College Eclipse Expedition), NRL, ESA, NASA, NatGeo.

The innermost image shows the Sun in ultraviolet light as recorded over a few hours by ESA’s PROBA2 mission in a Sun-synchronous low Earth orbit. This image is surrounded by a ground-based eclipse image, reproduced in blue, taken from Gabon by Allen Davis and Jay M. Pasachoff during the Williams College Eclipse Expedition. Further out is a circular blocked region used to artificially dim the central Sun by the Large Angle and Spectrometric Coronagraph (LASCO) instrument of the Sun-orbiting SOHO spacecraft. The outermost image – showing the outflowing solar corona – was taken by LASCO ten minutes after the eclipse and shows an outflowing solar corona.

Over the past few weeks, our Sun has been showing an unusually high amount of sunspots, CMEs, and flares – activity that was generally expected as the Sun is currently going through Solar Maximum – the busiest part of its 11 year solar cycle. This image is a picturesque montage of many solar layers at once that allows solar astronomers to better match up active areas on or near the Sun’s surface with outflowing jets in the Sun’s corona.


Earlier this year, NASA’s Interface Region Imaging Spectrograph (IRIS) spacecraft captured its first observations of a region of the Sun that is now possible to observe in detail: the lowest layers of the Sun’s atmosphere, the solar interface region.

Credit: NASA Goddard

The first images from IRIS show the solar interface region in unprecedented detail. They reveal dynamic magnetic structures and flows of material in the Sun’s atmosphere and hint at tremendous amounts of energy transfer through this little-understood region. These features may help power the Sun’s dynamic million-degree atmosphere and drive the solar wind that streams out to fill the entire Solar System.

The energy flowing through the interface region powers the upper layer of the Sun’s atmosphere, the corona, to temperatures greater than 1.8 million degrees Fahrenheit (1 million K). That is almost a thousand times hotter than the Sun’s surface. Understanding the interface region is important because it drives the solar wind and forms the ultraviolet emission that impacts near-Earth space and Earth’s climate.

IRIS is a NASA Small Explorer mission that was launched on June 27, 2013. Its instrument is a combination of an ultraviolet telescope and a spectrograph.

Links: NASA press release and IRIS mission homepage.

The National Radio Astronomy Observatory has released a new video about the Karl G. Jansky Very Large Array (VLA), narrated by actress Jodie Foster, for their Visitor Center near Socorro, New Mexico. (See Section 3.8d and Section 15.4.)

Credit: Wikipedia

Credit: Wikipedia

Called Beyond the Visible, the 24-minute movie tells the behind-the-scenes story of the operation and scientific achievements of the VLA, which has been at the forefront of astrophysical research since 1980. Spectacular ground and aerial footage of the iconic radio telescope is augmented by first-person interviews with staffers who keep the telescope working and scientists who use it to discover exciting new facts about the Universe. The documentary also depicts many of the technical tasks needed to keep the array functioning at the forefront of science.

Links: The NRAO has made the video available for viewing online here. An earlier movie “Into Deepest Space” tells the story of the Atacama Large Millimeter/submillimeter Array (ALMA).