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Cassini: Earth Between the Rings of Saturn

Posted: Fri Apr 21, 2017 3:48 am
by bystander
Earth Between the Rings of Saturn
NASA | JPL-Caltech | Cassini | 2017 Apr 20
[img3="Credit: NASA/JPL-Caltech/Space Science Institute"]https://saturn.jpl.nasa.gov/system/news ... -1280w.jpg[/img3][hr][/hr]
A new image from NASA's Cassini spacecraft shows planet Earth as a point of light between the icy rings of Saturn.

The spacecraft captured the view on April 12, 2017, at 10:41 p.m. PDT (1:41 a.m. EDT on April 13). Cassini was 870 million miles (1.4 billion kilometers) away from Earth when the image was taken. Although far too small to be visible in the image, the part of Earth facing Cassini at the time was the southern Atlantic Ocean.

Earth's moon is also visible nearby ...

The rings visible here are the A ring (at top) with the Keeler and Encke gaps visible, and the F ring (at bottom). During this observation Cassini was looking toward the backlit rings, making a mosaic of multiple images, with the sun blocked by the disk of Saturn. ...

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 5:51 pm
by starsurfer
Helix Nebula (NGC 7293)
http://www.caelumobservatory.com/gallery/helix.shtml
Copyright: Adam Block
Acknowledgement: Jay GaBany and Mel Martin
Click to view full size image

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 5:54 pm
by starsurfer
Arp 94
http://bf-astro.com/arp94/arp94.htm
Copyright: Bob Franke
arp94.jpg

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 5:56 pm
by starsurfer
vdB149 and vdB150
http://astrophotography.aa6g.org/Astrop ... -sx16.html
Copyright: Chuck Vaughn
vdb150.jpg

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 5:59 pm
by starsurfer
vdB149, vdB150 and LDN 1251
http://www.astrosurf.com/ilizaso/orriak ... Q_U16m.htm
Copyright: Iñaki Lizaso
LDN1251.jpg

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 6:02 pm
by starsurfer
M82
http://www.astrobin.com/232562/C/
Copyright: Dan Wilson
7d6d4c38e5f509b0d79927da8ea17fa1.1824x0.jpg

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 6:09 pm
by starsurfer
Malin 1
http://cfht.hawaii.edu/en/news/Malin1/
Copyright: S. Boissier/A&A/ESO/CFHT
malin1.jpg

Re: Found images: 2017 April

Posted: Sun Apr 23, 2017 6:12 pm
by starsurfer
M53
http://www.astrobin.com/292403/
Copyright: Tero Turunen
9f698257bd7ae6f21ae9639973df3f45.1824x0.jpg

Re: Found images: 2017 April

Posted: Mon Apr 24, 2017 1:06 am
by zAmboni
Not mine, but I think it is APOD worthy.

Image
Akaroa Aurora by Rob Dickinson, on Flickr

Re: Found images: 2017 April

Posted: Mon Apr 24, 2017 2:55 pm
by canopia

ESO: Cosmic Fireworks over Paranal

Posted: Mon Apr 24, 2017 3:19 pm
by bystander
Cosmic Fireworks over Paranal
ESO Picture of the Week | 2017 Apr 24
[img3="Petr Horálek/ESO"]https://cdn.eso.org/images/screen/potw1717a.jpg[/img3][hr][/hr]
In this incredible panorama, the night sky above ESO’s Very Large Telescope (VLT) displays our cosmic neighbourhood in all its glory.

The VLT is located 2635 metres above sea level at ESO’s Paranal Observatory in northern Chile. This image illustrates the importance, and the benefits, of placing astronomical telescopes in such remote places! Anyone making the long journey to the site — including ESO Photo Ambassador Petr Horálek, who captured this scene — is rewarded with a truly spectacular view.

On the right, behind the line of four 8.2-metre Unit Telescopes that together make up the VLT, the faint red and green hues of airglow can be seen illuminating the sky above the horizon. In addition zodiacal light is illuminating the sky as well. This diffuse light is caused by microscopic particles of light-scattering space dust in the plane of the Solar System.

While these features are beautiful, the most striking element of this image is undeniably the arc of the Milky Way. The bright arch of our home galaxy is peppered with dark filaments of dust, which absorb and obscure the light from the stars behind them, and bright patches where new stars are forming.

Just beneath the Milky Way lie two of our small galactic neighbours, the Large and Small Magellanic Clouds, and beneath them sit two of the VLT’s smaller 1.8-metre Auxiliary Telescopes.

HEIC: A Matter of Distance

Posted: Mon Apr 24, 2017 3:26 pm
by bystander
A Matter of Distance
ESA Hubble Picture of the Week | 2017 Apr 24
[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1717a.jpg[/img3][hr][/hr]
In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right — it has bright bursts of star formation and recorded supernova explosions— it blends into the background somewhat thanks to the gloriously bright star hogging the limelight next to it.

This bright object is a single and little-studied star named TYC 3203-450-1, located in the constellation of Lacerta (The Lizard), much closer than the much more distant galaxy. Only this way a normal star can outshine an entire galaxy, consisting of billions of stars. Astronomers studying distant objects call these stars “foreground stars” and they are often not very happy about them, as their bright light is contaminating the faint light from the more distant and interesting objects they actually want to study.

In this case TYC 3203-450-1 million times closer than NGC 7250 which lies over 45 million light-years away from us. Would the star be the same distance as NGC 7250, it would hardly be visible in this image.

Re: HEIC: A Matter of Distance

Posted: Mon Apr 24, 2017 5:34 pm
by Ann
bystander wrote:A Matter of Distance
ESA Hubble Picture of the Week | 2017 Apr 24
[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1717a.jpg[/img3][hr][/hr]
In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right — it has bright bursts of star formation and recorded supernova explosions— it blends into the background somewhat thanks to the gloriously bright star hogging the limelight next to it.

This bright object is a single and little-studied star named TYC 3203-450-1, located in the constellation of Lacerta (The Lizard), much closer than the much more distant galaxy. Only this way a normal star can outshine an entire galaxy, consisting of billions of stars. Astronomers studying distant objects call these stars “foreground stars” and they are often not very happy about them, as their bright light is contaminating the faint light from the more distant and interesting objects they actually want to study.

In this case TYC 3203-450-1 million times closer than NGC 7250 which lies over 45 million light-years away from us. Would the star be the same distance as NGC 7250, it would hardly be visible in this image.
That's fascinating! :D

It's a great-looking galaxy, obviously starbursting and quite dusty. But look at its nucleus, how faint and small it is! It isn't even obvious which extended whitish central point is the actual nucleus, although one of them is the likeliest candidate. But if a galaxy has such a tiny nucleus and such an unimpressive yellow bulge, it is certainly a light-weight and tiny galaxy that hasn't formed a lot of stars in the past. Now, however, it is making up for lost time! :D

And now look at that star, TYC 3203-450-1! It looks orange, and it is: its B-V is ~ 1.2 or 1.3. That is way redder than the B-V of the Sun, whose color index is 0.656 ± 0.005, and it is redder still than the galaxy, whose (dust-reddened) B-V is 0.640. Yet, a B-V of 1.2 or 1.3 isn't tremendously red for a star, and it doesn't suggest an M-type star to me. Maybe an M0V star, the brightest and the least red of the M-type main sequence stars? Is that possible?

Fantastically, according to my software Guide, the visual magnitude of TYC 3203-450-1 is 10.933. That is incredibly similar to the visual magnitude of Proxima Centauri, the most nearby of all stars after the Sun, whose visual magnitude (Proxima's, not the Sun's) is 10.977. These two stars are almost exactly the same apparent brightness! Yes, but Proxima is way redder, with a B-V index of 1.8, and its spectral class is M5V.

And now consider the distance to these two stars, and their intrinsic brightnesses. The distance to Proxima is 4.227 ± 0.014 light-years, and the star's brightness is 0.000055 times the Sun! That's so faint that it's amazing! Yes, but if I read the ESA/Hubble caption right, the distance to TYC 3203-450-1 would be 45 light-years, pretty much ten times farther away than Proxima! What does that tell us about the intrinsic brightness of TYC 3203-450-1? Is it a hundred times brighter than Proxima? So would that make it around 0.0055 times the luminosity of the Sun? That still seems low to me. Is TYC 3203-450-1 an M-type main sequence star after all, in spite of its relatively non-red appearance? Is it a star of spectral class M0V?

I'd love to hear your opinions on this! But if no one likes to chime in, I still find the portrait of the star and the galaxy (and the accompanying caption) incredibly interesting.

Ann

Re: Found images: 2017 April

Posted: Mon Apr 24, 2017 5:43 pm
by Ann
Oh! That's a mystery!

The brightest main sequence M-type star, according to Ken Croswell, is Lacaille 8760. According to my software Guide, Lacaille 8760 is a bit less than 13 light-years away, its spectral class is M1/M2V, its B-V is ~1.4 and its absolute visual luminosity is 0.027 times that of the Sun. That makes Lacaille 8760 way brighter, but also redder, than TYC 3203-450-1.

What a mystery!

Ann

Re: Found images: 2017 April

Posted: Tue Apr 25, 2017 2:23 pm
by starsurfer
Sh2-301
http://www.astropilar.com.ar/nebulosas/Sh2-301_1.html
Copyright: Ezequiel Bellocchio
Sh2-301.jpg

Re: Found images: 2017 April

Posted: Tue Apr 25, 2017 2:25 pm
by starsurfer
vdB13 and vdB16
http://www.pbase.com/tango33/image/162536948
Copyright: Kfir Simon
162536948.gVISmo8y.jpg

Re: Found images: 2017 April

Posted: Wed Apr 26, 2017 11:12 am
by starsurfer

Re: Found images: 2017 April

Posted: Wed Apr 26, 2017 11:14 am
by starsurfer

Re: Found images: 2017 April

Posted: Fri Apr 28, 2017 2:56 pm
by starsurfer
HFG 1 and Abell 6
http://www.astronomersdoitinthedark.com ... c=17&p=571
Copyright: Scott Rosen
HFG1-AB6.jpg

Re: Found images: 2017 April

Posted: Fri Apr 28, 2017 2:59 pm
by starsurfer
Fe 4
http://www.chart32.de/index.php/component/k2/item/188
Copyright: CHART32
Processing: Volker Wendel
Fe4.jpg

Re: Found images: 2017 April

Posted: Fri Apr 28, 2017 3:00 pm
by starsurfer

Re: Found images: 2017 April

Posted: Fri Apr 28, 2017 8:07 pm
by astrosirius
THE GREAT ORION NEBULA IN HIGH RESOLUTION BY THREE TELESCOPES AMATEURS

This image is the result of the efforts of three astrophotographers, Miguel Angel García Borrella, Antonio Pérez Ambite y Luis Romero Ventura, that using different equipment from their observatories located hundreds of kilometres away have chosen a common target to render the Orion Sword area (one of the most beautiful areas of our night sky) with the highest possible resolution and signal level.

Luis and Miguel Angel have contributed with high resolution images of the Great Orion nebula and the Running man nebula and Antonio with the magnificent field surrounding both nebulas. Miguel Angel has also contributed with a higher resolution image of the Trapezium composed by very short shots with a Takahasi Mewlon 250 telescope.

For all this work four remote observatories have been involved, gathering images during more than two months: The Astrosirius Observatory in Ager -Lleida-, The Hyperion observatory in Caraquiz -Guadalajara- , Observatory SPAG Monfragüe in Caceres Observatory e-EyE in Fregenal de la Sierra- Badajoz.

The project was to create an image with different equipments with the highest possible resolution and with the highest possible resolution and signal level to render one of the most beautiful areas of our skies. In this crazy idea three astrophotographers were invloved, Miguel Angel García Borrella,
Antonio Pérez Ambite and Lluís Romero Ventura.

Miguel and Lluís contributed the high resolution images of the Orion sword, and Antonio the magnificent field that surrounds the main ensemble. With it the objects in the final image are rendered deeper. It should be noted that the Antonio's Observatory is located 50 km away from Madrid, which means that the sky conditions are not optimal, due to light pollution.

The high resolution image of the Trapeziun area was taken with a Mewlon 250 from Takahashi, with very short exposure times, to avoid saturating the nebula core. In all this process, 4 remote observatories were involved, gathering images during more than two months, collecting the maximum possible signal taking into account the poor climatology and lunations: The Astrosirius Observatory in Ager -Lleida-,The Hyperion observatory in Caraquiz -Guadalajara- , the SPAG Monfragüe observatory in Caceres and the e-EyE Observatory in Fregenal de la Sierra- Badajoz, which contributed with the trapezium.

The final image is the result of assembling all six tiles, four of them with the same exposure times in all channels (L-RGB) but with two different telescopes, one to define the Trapezium and surrounding area, with Very short integration times in the Ha and RGB channels and, finally, hundreds of wide field images using medium exposure times that helped to resolve the dust clouds that surrounds the objects that compose the Orion Sword area.

At the end, the best tool of each processing program was used, and dozens of final images were processed during three months, to obtain the best resolution and colour of each one.

The total amount of integrated images were 808.

Details Data:

Place: Monfragüe-Cáceres-Spain // Àger-Lleida-Spain // Caraquiz-Guadalajara-Spain
SQM: 21.7 Average
Dates: From November 2016 till January 2017
Telescopes: ODK 16 f76.8 // Takahashi Mewlon 250 f/11 // GSO RC14 Truss // ASA N10
Mounts: TITAN 50 LOSMANDY // ASA DDM85 // ASA DDM85
Cameres: SBIG STL 11000 C2 /AOL // Moravian G3-11000 // FLI 16803
Exposure nebula x4 Mosaic HR: L: 21x900 sec bin1 // RGB: 21x900 sec bin1 // Ha: 21X1 sec bin1
Exposure nebula Surrounding: L: 340x300 sec bin1 // RGB: 100x300 sec bin1
Exposure Trapezium: L: 110x1 sec bin1 & 40x60sec bin1 // RGB: 40x60 sec bin1 // Ha: 10x600 sec bin1
Processing: Photoshop Cs6, MaximDL
Software: CAP5, The SKY6, pixinsight, CcdStack, Sequence ASA, CCD Commander.
Control Remote:Talon6 ROR

Copyright by:

Antonio Pérez Ambité: https://www.datsi.fi.upm.es/Hyperion/astronomia.html
Miguel Ángel García Borrella: http://observatoriosspag.es/index.htm
Lluís Romero Ventura: http://astrophotographysirius.com/

Re: Found images: 2017 April

Posted: Sat Apr 29, 2017 12:12 pm
by Ann
DavidLeodis wrote:
The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so. :)
Fascinating! I used David's link and came across the following information:
I am looking at the Galaxy NGC2415 with Advanced Camera for Surveys for Dr. Andrea Bellini

Proposal Abstract

With this exploratory program, we want to exploit some of the small gaps that are currently in the HST calendar each week to single-orbit image previously-unobserverd NGC/IC bright galaxies through the F606W filter of the ACS/WFC.;
NGC 2415. Photo: SDSS.
Fantastic and brilliant! I wasn't aware of NGC 2415, which turns out to be a massively starforming spiral galaxy - so starforming, in fact, that it has been classified as an irregular galaxy! Perhaps the faint companion at right has been feeding NGC 2415 gas, to set off a firebrand of star formation? Or perhaps the tidal forces in themselves were enough to get the fireworks going?

To me it's a pity that NGC 2415 will be imaged through the F606W filter only. That is actually the reason why I'm posting the SDSS picture here, so that you can appreciate the galaxy's brilliant blue colors.

Anyway, it appears that Hubble has indeed imaged NGC 2415 too, though perhaps not at high resolution. Here is Hubble picture of NGC 2415, processed by Gilles Chapdelaines.

Ann

Edit: I should have known that I had seen NGC 2415 even before I saw the picture at the Hubblesite link! My household god, James D Wray's The Color Atlas of Galaxies from 1988, offered a picture of it! The tiny picture was taken with the McDonald 2.7 meter telescope, and the galaxy looks basically all white. James D Wray wrote about NGC 2415:
An unusually high surface brightness galaxy. A range in surface brightness for galaxies of about this color index is seen in NGC 1313 (relatively low surface brightness), NGC 1309, and this galaxy.
The color index of NGC 2415 is B-V = 0.43 and U-B = -0.21.

Re: HEIC: Alien Aurorae on Uranus

Posted: Tue Sep 05, 2017 9:13 pm
by neufer
bystander wrote:Alien Aurorae on Uranus
ESA Hubble Picture of the Week | 2017 Apr 03
[img3="This is a composite image of Uranus by Voyager 2 and two different
observations made by Hubble — one for the ring and one for the aurorae.
Credit: ESA/Hubble & NASA, L. Lamy
"]https://cdn.spacetelescope.org/archives ... w1714a.jpg[/img3][hr][/hr]
Aurorae are caused by streams of charged particles like electrons, that come from various origins such as solar winds, the planetary ionosphere, and moon volcanism. They become caught in powerful magnetic fields and are channelled into the upper atmosphere, where their interactions with gas particles, such as oxygen or nitrogen, set off spectacular bursts of light. The alien aurorae on Jupiter and Saturn are well-studied, but not much is known about the aurorae of the giant ice planet Uranus. In 2011, the NASA/ESA Hubble Space Telescope became the first Earth-based telescope to snap an image of the aurorae on Uranus. In 2012 and 2014 astronomers took a second look at the aurorae using the ultraviolet capabilities of the Space Telescope Imaging Spectrograph (STIS) installed on Hubble.
Click to play embedded YouTube video.