Starship Asterisk*

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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!

<< Previously

NGC 6726-7
http://www.rolfolsenastrophotography.co ... X9fnRJx/X3
Copyright: Rolf Olsen

Eagle Nebula (M16)
https://www.eso.org/public/images/eso0926a/
Copyright: ESO

IC 5148
https://www.aao.gov.au/news-media/news/ ... r-division
Copyright: Steve Crouch, Dr. Travis Rector (Anchorage), AAO
Processing: Travis Rector http://members.pcug.org.au/~stevec/IC51 ... Gemini.htm
Processing: Steve Crouch

A Stubborn Dwarf Galaxy (LEDA 677373)
ESA Hubble Picture of the Week | 2016 July 04

[img3="Credit: ESA/Hubble, & NASA"]https://cdn.spacetelescope.org/archives ... w1627a.jpg[/img3][hr][/hr]

The fuzzy collection of stars seen in this NASA/ESA Hubble Space Telescope image forms an intriguing dwarf galaxy named LEDA 677373, located about 14 million light-years away from us.

Dwarf galaxies are small, faint collections of stars and gas. Their diverse properties make them intriguing objects to astronomers, but their small size means that we can only explore those that lie closest to us, within the Local Group, such as LEDA 677373.

This particular dwarf galaxy contains a plentiful reservoir of gas from which it could form stars. However, it stubbornly refuses to do so. In a bid to find out why, Hubble imaged the galaxy’s individual stars at different wavelengths, a method that allows astronomers to figure out a star’s age. These observations showed that the galaxy has been around for at least six billion years — plenty of time to form stars. So why has it not done so?

Rather than being stubborn, LEDA 677373 seems to have been the unfortunate victim of a cosmic crime. A nearby giant spiral galaxy, Messier 83, seems to be stealing gas from the dwarf galaxy, stopping new stars from being born.

Celestial Circles
ESO Picture of the Week | 2016 July 04

[img3="Credit: Adhemar Duro/ESO"]https://cdn.eso.org/images/screen/potw1627a.jpg[/img3][hr][/hr]

To take this Picture of the Week, ESO Photo Ambassador Adhemar Duro stopped by the roadside en route to one of ESO’s observing sites in Chile. This road winds up to the Atacama Large Millimeter/submillimeter Array, ALMA, located at an altitude of 5000 metres.

Due to the image’s long exposure time, the stars trace out circles on the night sky as they orbit the southern celestial pole, located at the centre of the image. Atop the celestial pole the Small and Large Magellanic Clouds — two satellite galaxies of the Milky Way, visible only in the southern hemisphere — can be seen as diffuse bluish clouds. On the left side of the image, an area densely populated by stars marks the centre of the Milky Way.

Even though the image was taken in the remote Atacama Desert, the distant lights of the small town San Pedro de Atacama are visible on the right edge of the image, brightening the dark night.

NGC 3579
http://www.astro-austral.cl/imagenes/ne ... 9/info.htm
Copyright: José Joaquín Pérez

Andromeda Galaxy (M31)
http://www.martinpughastrophotography.id.au
Copyright: Martin Pugh

NGC 90 and NGC 93
http://www.caelumobservatory.com/gallery/n90.shtml
Copyright: Adam Block/Mount Lemmon SkyCenter/University of Arizona NGC 90 is the blue spiral galaxy and NGC 93 is the galaxy to the right of it. Also includes many other galaxies.

Cave Nebula (Sh2-155)
http://astrophotography.aa6g.org/Astrop ... f8300.html
Copyright: Chuck Vaughn

vdB7
http://www.astrostammtisch.com/galerie/ ... p?pid=1649
Copyright: Martin Dandrea vdB7 is the reflection nebula near the bottom. The one in the middle is vdB9 and the one at the top is vdB8.

NGC 2818
http://www.chart32.de/index.php/component/k2/item/196
Copyright: CHART32
Processing: Johannes Schedler The open cluster and the planetary nebula are physically unrelated.

starsurfer wrote:NGC 90 and NGC 93
http://www.caelumobservatory.com/gallery/n90.shtml
Copyright: Adam Block/Mount Lemmon SkyCenter/University of Arizona
n90.jpg
NGC 90 is the blue spiral galaxy and NGC 93 is the galaxy to the right of it. Also includes many other galaxies.

Wonderful image!

Ann

starsurfer wrote:NGC 6726-7
http://www.rolfolsenastrophotography.co ... X9fnRJx/X3
Copyright: Rolf Olsen

Click to view full size image

And this one too...wonderful!

Ann

Milky Way Arching over La Silla
ESO Picture of the Week | 2016 July 11

[img3="Credit: Petr Horálek, ESO"]https://cdn.eso.org/images/screen/potw1628a.jpg[/img3][hr][/hr]

This stunning ultra high definition panorama, taken by ESO Photo Ambassador Petr Horálek, shows the Milky Way galaxy arching above ESO’s La Silla Observatory in Chile.

La Silla is located at the southern edge of the Atacama Desert, from where the observatory’s numerous telescopes observe the night sky — one of the darkest on the Earth — perched 2400 metres above sea level, and so making the most of the unrivalled atmospheric conditions at the site to reveal the cosmos in remarkable detail.

This image is certainly no different! Our galaxy’s cloudy and dusty structure appears as a brilliant and glowing coronet above the open dome of the MPG/ESO 2.2-metre telescope, which appears to be gobbling up the bright smudge of the Large Magellanic Cloud. Various clouds and nebulae, including the well-known Gum Nebula, stand out against the dark sky in the central–upper part of the image, shining in a range of pinkish hues.

Horálek’s camera also reveals various colours of the airglow, visible across the sky and near the horizon. An ESOcast dedicated to this peculiar sky phenomenon is available here.

A Lonely Birthplace (MCG+07-33-027)
ESA Hubble Picture of the Week | 2016 July 11

[img3="Credit: NASA, ESA/Hubble, and N. Grogin (STScI)"]https://cdn.spacetelescope.org/archives ... w1628a.jpg[/img3][hr][/hr]

This image was taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), and shows a starburst galaxy named MCG+07-33-027. This galaxy lies some 300 million light-years away from us, and is currently experiencing an extraordinarily high rate of star formation — a starburst. Normal galaxies produce only a couple of new stars per year, but starburst galaxies can produce a hundred times more than that! As MCG+07-33-027 is seen face-on, the galaxy’s spiral arms and the bright star-forming regions within them are clearly visible and easy for astronomers to study.

In order to form newborn stars, the parent galaxy has to hold a large reservoir of gas, which is slowly depleted to spawn stars over time. For galaxies in a state of starburst, this intense period of star formation has to be triggered somehow — often this happens due to a collision with another galaxy. MCG+07-33-027, however, is special; while many galaxies are located within a large cluster of galaxies, MCG+07-33-027 is a field galaxy, which means it is rather isolated. Thus, the triggering of the starburst was most likely not due to a collision with a neighbouring or passing galaxy and astronomers are still speculating about the cause.

Ann wrote:

starsurfer wrote:NGC 6726-7
http://www.rolfolsenastrophotography.co ... X9fnRJx/X3
Copyright: Rolf Olsen

Click to view full size image

And this one too...wonderful!

Ann

Considering your love of the colour blue, your reaction is unsurprising! I'm glad I've made you happy!

Seagull Nebula (IC 2177)
http://www.astroimager.net/Page-130GT-CCD-321.html
Copyright: Jim Janusz

Heron Galaxy (NGC 5394-5)
http://bf-astro.com/ngc5395/ngc5395.htm
Copyright: Bob Franke

bystander wrote:A Lonely Birthplace (MCG+07-33-027)
ESA Hubble Picture of the Week | 2016 July 11

[img3="Credit: NASA, ESA/Hubble, and N. Grogin (STScI)"]https://cdn.spacetelescope.org/archives ... w1628a.jpg[/img3][hr][/hr]

This image was taken by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), and shows a starburst galaxy named MCG+07-33-027. This galaxy lies some 300 million light-years away from us, and is currently experiencing an extraordinarily high rate of star formation — a starburst. Normal galaxies produce only a couple of new stars per year, but starburst galaxies can produce a hundred times more than that! As MCG+07-33-027 is seen face-on, the galaxy’s spiral arms and the bright star-forming regions within them are clearly visible and easy for astronomers to study.

In order to form newborn stars, the parent galaxy has to hold a large reservoir of gas, which is slowly depleted to spawn stars over time. For galaxies in a state of starburst, this intense period of star formation has to be triggered somehow — often this happens due to a collision with another galaxy. MCG+07-33-027, however, is special; while many galaxies are located within a large cluster of galaxies, MCG+07-33-027 is a field galaxy, which means it is rather isolated. Thus, the triggering of the starburst was most likely not due to a collision with a neighbouring or passing galaxy and astronomers are still speculating about the cause.

I'm surprised to see this galaxy described as a starburst galaxy.
In my own amateur opinion, starburst galaxies basically come in two flavors. There are the relatively well-ordered circumnuclear ring starburst spiral galaxies, like M94 at left and M100 at right. The contrast between the starburst nuclear ring and the rest of the galaxy is very obvious in both images. Typically, the circumnuclear rings are orders of magnitude brighter than other sites of star formation in the galaxies, but these central rings of starbursts don't disturb the well-ordered overall shape of the galaxy. (As for M94, according to Wikipedia, its bright inner ring is "sometimes referred to as a starburst ring", suggesting not everybody views it as such.).





Then there are the messy starbursts, where either the entire galaxy becomes distorted like NGC 1313 at right, or where a massive central starburst produces huge amounts of dust and drives lots of gas and dust out of the galaxy.








But MCG+07-33-027 doesn't look much like that. It is very well-ordered, with symmetrical spiral arms. It doesn't have a strikingly bright circumnuclear ring. It lacks any conspicuous large bright nebulas or clusters. It isn't obviously dusty.

I admit that there are some similarities between MCG+07-33-027 and M94. They are certainly not identical or even fraternal twins, because MCG+07-33-027 definitely has more star formation outside the ring than M94 and a less conspicuous circumnuclear ring. If indeed MCG+07-33-027 is a milder version of M94, then it would be interesting to know if MCG+07-33-027 is also as tiny as M94. M94 is surprisingly diminutive, considerably smaller than M33. It would be interesting if MCG+07-33-027 was small, because in the nearby universe starbursts mostly occur is small galaxies.


Ann

IC 4592 and IC 4601
http://www.astrosurf.com/ilizaso/orriak ... Q_U16m.htm
Copyright: Iñaki Lizaso

NGC 6753
Geck has processed some HST wideband leftovers and created a truly stunning picture of galaxy NGC 6753. You have to watch the large size of this image.

Ann

Ann wrote:NGC 6753

NGC 6753. Processing:
Judy Schmidt.

Geck has processed some HST wideband leftovers and created a truly stunning picture of galaxy NGC 6753. You have to watch the large size of this image.

Ann

This is a wonderful image of a neglected galaxy in Pavo! Also technically it's geck, not "Geck".

LBN 552
http://www.alessandrofalesiedi.it/deep-sky/lbn-552/
Copyright: Alessandro Falesiedi

Sh2-173
http://www.astrobin.com/230172/
Copyright: Tero Turunen