Found images: 2017 April

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Cassini: Earth Between the Rings of Saturn

Postby bystander » Fri Apr 21, 2017 3:48 am

Earth Between the Rings of Saturn
NASA | JPL-Caltech | Cassini | 2017 Apr 20

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. ...
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 5:51 pm

Helix Nebula (NGC 7293)
http://www.caelumobservatory.com/gallery/helix.shtml
Copyright: Adam Block
Acknowledgement: Jay GaBany and Mel Martin

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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 5:54 pm

Arp 94
http://bf-astro.com/arp94/arp94.htm
Copyright: Bob Franke
arp94.jpg
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 5:56 pm

vdB149 and vdB150
http://astrophotography.aa6g.org/Astrophotos/vdb150-svs130-sx16.html
Copyright: Chuck Vaughn
vdb150.jpg
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 5:59 pm

vdB149, vdB150 and LDN 1251
http://www.astrosurf.com/ilizaso/orriak/3maila/LDN1235_LDN1251_FSQ_U16m.htm
Copyright: Iñaki Lizaso
LDN1251.jpg
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 6:02 pm

M82
http://www.astrobin.com/232562/C/
Copyright: Dan Wilson
7d6d4c38e5f509b0d79927da8ea17fa1.1824x0.jpg
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 6:09 pm

Malin 1
http://cfht.hawaii.edu/en/news/Malin1/
Copyright: S. Boissier/A&A/ESO/CFHT
malin1.jpg
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Re: Found images: 2017 April

Postby starsurfer » Sun Apr 23, 2017 6:12 pm

M53
http://www.astrobin.com/292403/
Copyright: Tero Turunen
9f698257bd7ae6f21ae9639973df3f45.1824x0.jpg
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Re: Found images: 2017 April

Postby zAmboni » Mon Apr 24, 2017 1:06 am

Not mine, but I think it is APOD worthy.

Image
Akaroa Aurora by Rob Dickinson, on Flickr

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Re: Found images: 2017 April

Postby canopia » Mon Apr 24, 2017 2:55 pm


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ESO: Cosmic Fireworks over Paranal

Postby bystander » Mon Apr 24, 2017 3:19 pm

Cosmic Fireworks over Paranal
ESO Picture of the Week | 2017 Apr 24

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.
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HEIC: A Matter of Distance

Postby bystander » Mon Apr 24, 2017 3:26 pm

A Matter of Distance
ESA Hubble Picture of the Week | 2017 Apr 24

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.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: HEIC: A Matter of Distance

Postby Ann » Mon Apr 24, 2017 5:34 pm

bystander wrote:A Matter of Distance
ESA Hubble Picture of the Week | 2017 Apr 24

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
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Re: Found images: 2017 April

Postby Ann » Mon Apr 24, 2017 5:43 pm

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
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Re: Found images: 2017 April

Postby starsurfer » Tue Apr 25, 2017 2:23 pm

Sh2-301
http://www.astropilar.com.ar/nebulosas/Sh2-301_1.html
Copyright: Ezequiel Bellocchio
Sh2-301.jpg
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Re: Found images: 2017 April

Postby starsurfer » Tue Apr 25, 2017 2:25 pm

vdB13 and vdB16
http://www.pbase.com/tango33/image/162536948
Copyright: Kfir Simon
162536948.gVISmo8y.jpg
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Re: Found images: 2017 April

Postby starsurfer » Wed Apr 26, 2017 11:12 am


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Re: Found images: 2017 April

Postby starsurfer » Wed Apr 26, 2017 11:14 am

CG 11
http://www.tvdavisastropics.com/astroimages-1_0000c1.htm
Copyright: Thomas Davis
astroimages-1_i000148.jpg
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