Found Images: 2019 July

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Have you seen a great image or video somewhere that you think would make a great APOD? Nominate it for APOD! Please post as much information here as you have about the image/video with a link to any source(s) for it you know of here, and the editors will take a look.

When posting the image itself, please do not post anything larger than a thumbnail here; please honor the copyright holder's copyright.

Please keep hotlinked images under 400K.

Thank you!

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Highest Resolution Image of the 1919 Solar Eclipse
ESO Picture of the Week | 2019 July 01

Credit: ESO/Landessternwarte Heidelberg-Königstuhl/F. W. Dyson, A. S. Eddington, & C. Davidson

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Almost exactly 100 years ago, a remarkable event occurred: a total solar eclipse. This eclipse was special in more ways than one. Firstly, at just under seven minutes in duration, it was the longest such eclipse in over 500 years. Secondly, it was used by astronomers to explore the then-new theory of general relativity — with successful and groundbreaking results.

Einstein published his general theory of relativity in 1915. The total solar eclipse of 1919 offered the perfect opportunity to test it experimentally, by exploring whether — and how — the immense gravity of the Sun bends and distorts incoming light from more distant stars, as predicted by Einstein’s theory. For a brief moment during the eclipse, the Moon would block the Sun’s light in the sky and make visible some of the stars that lie close to the line of sight of the Sun, not normally visible during the daytime. By measuring the positions of these stars during the eclipse and comparing them to their positions at night, when the sun is not in the field of view, it would be possible to determine whether their light rays bends while passing close to the Sun.

Three astronomers — Arthur Eddington, Frank Watson Dyson, and Andrew Crommelin — played key roles in this 1919 experiment. Eddington and Crommelin travelled to locations at which the eclipse would be total — Eddington to the West African island of Príncipe, Crommelin to the Brazilian town of Sobral — while Dyson coordinated the attempt from England.

Eddington and Crommelin imaged the eclipse using the technology of the time: photographic plates made of glass. Sadly, the original plates from the 1919 expedition (one of which was reproduced in Dyson’s original paper) have been lost — but, luckily, copies of one of the plates were made and sent to observatories around the world to allow scientists everywhere to see the evidence in support of relativity with their own eyes. One copy of a plate from Sobral went to Landessternwarte Heidelberg-Königstuhl, who recently scanned theirs as part of the Heidelberg Digitized Astronomical Plates (HDAP) project [1].

The image shown here is arguably the highest resolution image of the 1919 eclipse, and is the result of applying modern image processing techniques — including image restoration, noise reduction, and removal of artifacts — to that plate copy (un-annotated version here). It unveils stunning details in the solar corona, a giant prominence emerging from the upper right part of the Sun, and stars in the constellation of Taurus (The Bull) that were used to confirm general relativity’s predictions [2].

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In Bloom
ESA Hubble Picture of the Week | 2019 July 01

Image Credit: ESA/Hubble, NASA, L. Ho

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This NASA/ESA Hubble Space Telescope Picture of the Week shows bright, colourful pockets of star formation blooming like roses in a spiral galaxy named NGC 972.

The orange-pink glow is created as hydrogen gas reacts to the intense light streaming outwards from nearby newborn stars; these bright patches can be seen here amid dark, tangled streams of cosmic dust.

Astronomers look for these telltale signs of star formation when they study galaxies throughout the cosmos, as star formation rates, locations, and histories offer critical clues as to how these colossal collections of gas and dust have evolved over time. New generations of stars contribute to — and are also, in turn, influenced by — the broader forces and factors that mould galaxies throughout the Universe, such as gravity, radiation, matter, and dark matter.

German-British astronomer William Herschel is credited with the discovery of NGC 972 in 1784. Astronomers have since measured its distance, finding it to be just under 70 million light-years.

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IC 5148
https://astrodonimaging.com/gallery/ic-5148-with-halo/
Copyright: Don Goldman

This image was used in this scientific study.

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Longmore 5
http://www.chart32.de/index.php/component/k2/item/298
Copyright: CHART32
Processing: Johannes Schedler

Click to view full size image

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Owl Nebula (M97)
https://pbase.com/skybox/image/169181267
Copyright: Kevin Quin

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IC 417
https://www.hansonastronomy.com/sh2-234
Copyright: Mark Hanson

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Omega Centauri (NGC 5139)
http://www.cielaustral.com/galerie/photo97.htm
Copyright: Ciel Austral

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Sandqvist 156
http://www.atacama-photographic-observa ... php?id=107
Copyright: Thierry Demange, Richard Galli and Thomas Petit

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KjPn 8
http://www.capella-observatory.com/Imag ... /KjPn8.htm
Copyright: Stefan Binnewies and Josef Pöpsel

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NGC 300
http://www.karelteuwen.be/photo_page.ph ... 0&album=18
Copyright: Karel Teuwen

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Red and Long Dead
ESO Picture of the Week | 2019 Jul 08

Image Credit: ESO/VLT/FORS

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This red-hued cloud of gas is named Abell 24, and is located in the constellation of Canis Minor (The Lesser Dog). It is something known as a planetary nebula — a burst of gas and dust created when a star dies and throws its outer layers into space. Despite the name, planetary nebulae have nothing to do with planets. The term was coined by William Herschel, who also famously discovered Uranus; in a time of low-resolution astronomy, these nebulous objects appeared to resemble giant planets swimming in a dark cosmos.

A Sun-like star spends most of its life converting hydrogen into helium in its core. In its twilight years the star runs out of fuel and becomes unbalanced; it can no longer resist the inward crush of gravity and the core begins to collapse. The temperature in the core rises dramatically while the cooler outer layers expand, causing the entire star to bloat into a red giant. When the Sun begins its transformation into a red giant it will expand to completely engulf the innermost planets and possibly also the Earth, growing to over 250 times its current radius! Strong winds then expel the gaseous outer layers of the star, forming a shell of gas that spreads out into the vastness of space. The red giant's venting atmosphere will eventually expose its hot, luminous remnant core, which will emit fierce ultraviolet radiation and ionise the surrounding gas. This image shows the faint nebulous glow of a stellar swansong — the bright remnant of a long-dead star.

Taken with the VLT’s FORS (FOcal Reducer and Spectrograph) instrument, this image is part of the ESO Cosmic Gems programme, an initiative to produce images of scientifically interesting and visually attractive objects using ESO telescopes for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

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Galactic Cherry Blossom
ESA Hubble Picture of the Week | 2019 Jul 08

Image Credit: ESA/Hubble, NASA, R. Jansen

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The galaxy NGC 1156 resembles a delicate cherry blossom tree flowering in springtime in this Hubble Picture of the Week. The many bright "blooms" within the galaxy are in fact stellar nurseries — regions where new stars are springing to life. Energetic light emitted by newborn stars in these regions streams outwards and encounters nearby pockets of hydrogen gas, causing it to glow with a characteristic pink hue.

NGC 1156 is located in the constellation of Aries (The Ram). It is classified as a dwarf irregular galaxy, meaning that it lacks a clear spiral or rounded shape, as other galaxies have, and is on the smaller side, albeit with a relatively large central region that is more densely packed with stars.

Some pockets of gas within NGC 1156 rotate in the opposite direction to the rest of the galaxy, suggesting that there has been a close encounter with another galaxy in NGC 1156's past. The gravity of this other galaxy — and the turbulent chaos of such an interaction — could have scrambled the likely more orderly rotation of material within NGC 1156, producing the odd behaviour we see today.

[Ann]

Galactic Cherry Blossom
ESA Hubble Picture of the Week | 2019 Jul 08

Image Credit: ESA/Hubble, NASA, R. Jansen

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The galaxy NGC 1156 resembles a delicate cherry blossom tree flowering in springtime in this Hubble Picture of the Week. The many bright "blooms" within the galaxy are in fact stellar nurseries — regions where new stars are springing to life. Energetic light emitted by newborn stars in these regions streams outwards and encounters nearby pockets of hydrogen gas, causing it to glow with a characteristic pink hue.

NGC 1156 is located in the constellation of Aries (The Ram). It is classified as a dwarf irregular galaxy, meaning that it lacks a clear spiral or rounded shape, as other galaxies have, and is on the smaller side, albeit with a relatively large central region that is more densely packed with stars.

Some pockets of gas within NGC 1156 rotate in the opposite direction to the rest of the galaxy, suggesting that there has been a close encounter with another galaxy in NGC 1156's past. The gravity of this other galaxy — and the turbulent chaos of such an interaction — could have scrambled the likely more orderly rotation of material within NGC 1156, producing the odd behaviour we see today.

Click to view full size image

UGC 4459. NASA/ESA/Hubble/Judy Schmidt.

The picture of NGC 1156 is gorgeous, but I note, with some surprise, that it was made using only two filters whose wavelengths are relatively close to one another - 625 nm, or orange, and 658 nm, red ionized nitrogen.

The fact that no blue filter was used for this obviously intrinsically blue galaxy makes it rather hard to judge the exact colors of the stellar populations in this galaxy. Practically all the individual stars in the center of the galaxy look blue in the picture, which is not what we would expect.

Compare the picture of NGC 1156 with the picture of UGC 4459. The latter was made using three very different filters, one infrared, one visible and one ultraviolet. Note the "natural" star colors that this picture displays, where only a relatively small number of stars are definitely blue, some are clearly yellow, and many are neutral-colored.

Well done, Geck.

Ann

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NGC 6726
http://www.astrostudio.at/1_Deep%20Sky% ... 72ac8d0a3b
Copyright: Gerald Rhemann

Click to view full size image

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Abell 61
https://www.britastro.org/node/18517
Copyright: Peter Goodhew

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Abell 35
https://www.flickr.com/photos/97807083@N00/46285431452/
Copyright: Terry Robison

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NGC 1333
https://www.astrobin.com/373084/
Copyright: Marco Favro

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NGC 5949
https://www.spacetelescope.org/images/potw1732a/
Copyright: ESA/Hubble & NASA

Click to view full size image

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NGC 6210
http://www.astro-koop.de/?attachment_id=2020
Copyright: Stefan Heutz, Wolfgang Ries and Michael Breite

Click to view full size image

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Sh2-104
http://afesan.es/Deepspace/slides/SH2%2 ... us%29.html
Copyright: Antonio Sánchez

Sh2-104 is the small round emission nebula near the bottom left corner.

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A Game-Changer
ESO Picture of the Week | ALMA | 2019 Jul 15

Credit: ALMA (ESO/NAOJ/NRAO)/K. Blundell, R. Laing, S. Lee & A. Richards, ApJL 2018

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This is SS 433, a microquasar first discovered forty years ago and located about 18 000 light-years away in the constellation of Aquila (The Eagle). This image, captured for the very first time at submillimeter wavelengths by the Atacama Large Millimeter/submillimeter Array (ALMA), is special because it shows the jets emitted by a hot, swirling disc of material encircling the black hole at SS 433’s centre. Owing to its relative proximity, SS 433 is a particularly useful object for researchers looking to learn more about microquasars and the jets they emit.

The corkscrew shape visible here is created by a phenomenon known as precession; as they move outwards through space, these two jets are slowly tumbling around an axis in a similar way to the motion of a gyroscope or a spinning top slowing down, the orientation of their rotational axes changing as they do so. The scale of this corkscrew is enormous, at 5000 times the size of the Solar System.

One remarkable aspect of this observation is that its detailed shape was entirely predicted from spectroscopic measurements by the Global Jet Watch telescopes in the preceding year before the ALMA observations were made. The sequence of these observations allowed researchers to make and test predictions about the paths the jets would take, representing a new milestone in the study of microquasars. The observations have also resolved the question of why the jets are still hot at such great distances from their origin — ALMA’s sensitivity enabled researchers to identify that reheating of the plasma occurs when successive jet surges expand and collide with one another.

SS433's Jet Trace from ALMA Imaging and Global Jet Watch Spectroscopy:
Evidence for Post-Launch Particle Acceleration ~ Katherine M. Blundell et al

• Astrophysical Journal Letters 867(2):L25 (2018 Nov 10) DOI: 10.3847/2041-8213/aae890
• arXiv.org > astro-ph > arXiv:1811.00760 > 02 Nov 2018

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A Beautiful Whorl
ESA Hubble Picture of the Week | 2019 Jul 15

Image Credit: ESA/Hubble & NASA, L. Ho

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Galaxies come in many shapes and sizes. One of the key galaxy types we see in the Universe is the spiral galaxy, as demonstrated in an especially beautiful way by the subject of this Hubble Picture of the Week, NGC 2985. NGC 2985 lies roughly over 70 million light years from the Solar System in the constellation of Ursa Major (The Great Bear).

The intricate, near-perfect symmetry on display here reveals the incredible complexity of NGC 2985. Multiple tightly-wound spiral arms widen as they whorl outward from the galaxy’s bright core, slowly fading and dissipating until these majestic structures disappear into the emptiness of intergalactic space, bringing a beautiful end to their starry splendour.

Over aeons, spiral galaxies tend to run into other galaxies, often resulting in mergers. These coalescing events scramble the winding structures of the original galaxies, smoothing and rounding their shape. These objects possess a beauty all their own, distinct from the spiral galaxies from whence they came.

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GGD 27
http://members.pcug.org.au/~stevec/GGD2 ... 3_RC14.htm
Copyright: Steve Crouch

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HiRISE Spots Curiosity Rover at Mars's "Woodland Bay"
NASA | JPL-Caltech | MRO HiRISE | MSL Curiosity | 2019 Jul 12

NASA's Curiosity Mars rover can be seen in this image taken from space on May 31, 2019, by the HiRISE camera aboard the Mars Reconnaissance Orbiter. In the image, Curiosity appears as a bluish speck.Credit: NASA/JPL-Caltech/Univ of Arizona

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A dramatic Martian landscape can be seen in a new image taken from space, showing NASA's Curiosity rover examining a location called "Woodland Bay." It's just one of many stops the rover has made in an area referred to as the "clay-bearing unit" on the side of Mount Sharp, a 3-mile-tall (5-kilometer-tall) mountain inside of Gale Crater.

The image was taken on May 31, 2019, by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter (MRO). In the image, Curiosity appears as a bluish speck. Vera Rubin Ridge cuts across the scene north of the rover, while a dark patch of sand lies to the northeast.

Look carefully at the inset image, and you can make out what it is likely Curiosity's "head," technically known as the remote sensing mast. A bright spot appears in the upper-left corner of the rover. At the time this image was acquired, the rover was facing 65 degrees counterclockwise from north, which would put the mast in about the right location to produce this bright spot.

Mirror-like reflections off smooth surfaces show up as especially bright spots in HiRISE images. For the camera to see these reflections on the rover, the Sun and MRO need to be in just the right locations. This enhanced-color image of Curiosity shows three or four distinct bright spots that are likely such reflections.