Starship Asterisk*

Image Credit: ESO/Mahdi Zamani

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This picture of the week shows two of the three new ExTrA telescopes hosted at ESO’s La Silla Observatory in Chile. Situated over 2000 meters above sea level, these telescopes scour the skies for Earth-sized worlds around M class stars, which are stars smaller than the Sun.

A “shooting star” flashes across the night sky above the telescopes and towards the horizon of the Atacama Desert in Chile. Shooting stars are not actually stars, but small bits of rock or dust that enter the Earth’s orbit and burn up in the atmosphere. Before they enter Earth’s atmosphere, these tiny celestial bodies are called meteoroids.

The dramatic streaks of light caused by meteoroids burning up are not just beautiful and exciting, but also informative. Scientists look at the path and brightness of a meteoroid to determine where in the Solar System it came from and what it is composed of. If a meteoroid makes it through Earth’s atmosphere to the ground it is then called a meteorite. Scientists can study meteorites to learn more about the history of the Solar System.

Image Credit: ESA/Hubble & NASA, T. Armandroff

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As beautiful as the surrounding space may be, the sparkling galaxy in the foreground of this image from the NASA/ESA Hubble Space Telescope undeniably steals the show.

This spotlight-hogging galaxy, seen set against a backdrop of more distant galaxies of all shapes and sizes, is known as PGC 29388. Although it dominates in this image, this galaxy is a small player on the cosmic stage, and is known as a dwarf elliptical galaxy. As the “dwarf” moniker suggests, the galaxy is on the smaller side, and boasts a “mere” 100 million to a few billion stars — a very small number indeed when compared to the Milky Way's population of around 250 to 400 billion stellar residents.

starsurfer wrote: ↑Wed Apr 01, 2020 8:29 pm Tarantula Nebula (NGC 2070) region
https://www.glitteringlights.com/Images ... /i-Ftkz8xk
Copyright: Marco Lorenzi
NGC_2070.jpg

Susanna Kohler wrote:

Click to view full size image

This still from a computer simulation shows the formation of a very early star system in the universe. In the gas-density volume rendering above, a binary composed of a single protostar (left) and a mini-triple set of protostars (right) has recently formed from the collapse and fragmentation of a primordial cloud of gas. The simulation, conducted by Kazuyuki Sugimura (University of Maryland; Tohoku University, Japan) and collaborators, follows not only what happens in the initial collapse of the cloud, but also how the subsequent evolution over the next ~100,000 years is influenced by the hot, ionizing radiation of the multiple stars that are forming (visible in this image as yellow bubbles of ionized gas around the poles of the stellar systems). Sugimura and collaborators’ work suggests that the first stars in the universe commonly formed as massive binary or multiple systems.

• Astrophysical Journal Letters 892(1):L14 (2020 Mar 20) DOI: 10.3847/2041-8213/ab7d37
• arXiv.org > astro-ph > arXiv:2002.00012 > 31 Jan 2020

starsurfer wrote: ↑Wed Apr 22, 2020 4:26 pm vdB152
https://aipastroimaging.com/vdb152/
Copyright: Álvaro Ibáñez Pérez
VdB152.jpg

Ann wrote: ↑Thu Apr 23, 2020 5:06 am

starsurfer wrote: ↑Wed Apr 22, 2020 4:26 pm vdB152
https://aipastroimaging.com/vdb152/
Copyright: Álvaro Ibáñez Pérez
VdB152.jpg

I don't usually like the appearance of VdB 152, which I often find graceless. But this image is fascinating. I love the red streak running diagonally across the image, and the faint bluish elongated cloud running diagonally at almost right angles to the red streak. And the "planetary nebula impostor" (I don't think it's a real one) at upper left adds to the visual interest of the image.

Ann

Image Credit: Petr Horálek/ESO

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This beautiful Picture of the Week shows the magnificent Milky Way stretching over the Very Large Telescope (VLT) at ESO’s Paranal Observatory, demonstrating the astounding level of detail visible in the night sky from this remote site in the Chilean Atacama Desert.

At Paranal, the star-studded Milky Way is so bright that on a dark night it can cast shadows of the people and objects beneath it! This image shows countless stars, dark lanes of dust, and glowing clouds of celestial gas. These clouds are sites of star formation; energetic radiation emanating from newborn stars ionizes the hydrogen in the gas clouds, causing them to glow a rosy red. Below the Milky Way is the Large Magellanic Cloud, a dwarf galaxy orbiting the Milky Way.

The night sky is observed every night by the world’s most advanced optical observatory the VLT. This telescope is actually made up of four Unit Telescopes, all of which can be seen in this image, and four smaller moveable Auxiliary Telescopes (one of which can been in the distance to the left of the foreground Unit Telescope). Each Unit Telescope has a main mirror measuring 8.2 metres in diameter, and is able to see objects four billion times fainter than those we can see with the unaided eye. Just imagine what the VLT can see in this glorious night sky!

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

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This sparkling spiral galaxy looks almost stretched across the sky in this new image from the NASA/ESA Hubble Space Telescope. Known as NGC 4100, the galaxy boasts a neat spiral structure and swirling arms speckled with the bright blue hue of newly formed stars.

Like so many of the stunning images of galaxies we enjoy today, this image was captured by Hubble’s Advanced Camera for Surveys (ACS). This remarkable instrument was installed in 2002, and, with some servicing over the years by intrepid astronauts, is still going strong. You can access many of the stunning images captured by the ACS here, featuring objects from out-of-this-world spiral galaxies to dark, imposing nebulae, bizarre cosmic phenomena, and sparkling clusters made up of thousands upon thousands of stars.

bystander wrote: ↑Mon Apr 27, 2020 5:55 pm A Stretched Spiral
ESA Hubble Picture of the Week | 2020 Apr 27

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

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This sparkling spiral galaxy looks almost stretched across the sky in this new image from the NASA/ESA Hubble Space Telescope. Known as NGC 4100, the galaxy boasts a neat spiral structure and swirling arms speckled with the bright blue hue of newly formed stars.

Like so many of the stunning images of galaxies we enjoy today, this image was captured by Hubble’s Advanced Camera for Surveys (ACS). This remarkable instrument was installed in 2002, and, with some servicing over the years by intrepid astronauts, is still going strong. You can access many of the stunning images captured by the ACS here, featuring objects from out-of-this-world spiral galaxies to dark, imposing nebulae, bizarre cosmic phenomena, and sparkling clusters made up of thousands upon thousands of stars.

Ann wrote: ↑Mon Apr 27, 2020 6:43 pm

bystander wrote: ↑Mon Apr 27, 2020 5:55 pm A Stretched Spiral
ESA Hubble Picture of the Week | 2020 Apr 27

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

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This sparkling spiral galaxy looks almost stretched across the sky in this new image from the NASA/ESA Hubble Space Telescope. Known as NGC 4100, the galaxy boasts a neat spiral structure and swirling arms speckled with the bright blue hue of newly formed stars.

Like so many of the stunning images of galaxies we enjoy today, this image was captured by Hubble’s Advanced Camera for Surveys (ACS). This remarkable instrument was installed in 2002, and, with some servicing over the years by intrepid astronauts, is still going strong. You can access many of the stunning images captured by the ACS here, featuring objects from out-of-this-world spiral galaxies to dark, imposing nebulae, bizarre cosmic phenomena, and sparkling clusters made up of thousands upon thousands of stars.

Nothing interests me more about a scientifically made image of a galaxy than the question of what filters were used in order to produce the picture. Sadly, no information about the filters was given on the Space Telescope page.

So I'm going to have a guess. I guess that the picture of NGC 4100 is a two-filter image. And I guess that one of the two filters used was the longpass near infrared 814 nm one, which is a true mainstay in Hubble pictures. The infrared light detected by the 814 nm filter would be mapped as red.

What about the other filter? My guess is that it was a hydrogen alpha filter, whose job it was to detect emission nebulas emitting red light at 656 nm (or slightly longer due to the expansion of the Universe, maybe 658 nm). The very red emission nebula light detected by the Hydrogen alpha filter would then be mapped as blue.

That's my guess.

Ann