Starship Asterisk*

[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. ...

[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.

[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.

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.

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.

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.;

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.

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.