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Scientists Photographed Our ‘Galactic Bulge’ Using a Dark Energy Camera

In an effort to research how the center of the Milky Way Galaxy formed what is known as a “galactic bulge,” Scientists used a Dark Energy Camera to survey a portion of the sky and capture a photo of billions of stars.

NASA’s Hubblesite describes our galaxy as “shaped like two fried eggs glued back-to-back.” This depiction makes clear the central bulge of stars that sits in the middle of a sprawling disk of stars that we usually see in two-dimensional drawings. You can get a better idea of how that looks thanks to a rendering from the ESA below:

This makeup is thought to be a common feature among myriad spiral galaxies like the Milky Way, and scientists desired to study how the bulge was formed. Were the stars within the bulge born early in our galaxy’s history, 10 to 12 billion years ago, or did the bulge build up over time through multiple episodes of star formation?

“Many other spiral galaxies look like the Milky Way and have similar bulges, so if we can understand how the Milky Way formed its bulge then we’ll have a good idea for how the other galaxies did too,” said co-principal investigator Christian Johnson of the Space Telescope Science Institute in Baltimore, Maryland.

The team surveyed a portion of our sky covering more than 200 square degrees – an area approximately equivalent to 1,000 full Moons – using the Dark Energy Camera (DECam) on the Victor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in Chile, a Program of NSF’s NOIRLab.

This image shows a wide-field view of the center of the Milky Way with a pull-out image taken by the DECam.

The scientific sensor array on the DECam is made up of 62 separate 2048×4096 pixel backside-illuminated CCD sensors, totaling 520 megapixels. An additional 12 2048×2048 pixel CCD sensors (50 megapixels) are used to guide the telescope, monitor focus, and help with alignment.

This wide-field camera is capable of capturing 3 square degrees of sky in a single exposure and allowed the team to collect more than 450,000 individual photographs. From that data the team was able to determine the chemical compositions for millions of stars. The image below contains billions of stars:

You can view a pannable and zoomable version of this image here. It uses the same interface as the giant 2.5 gigapixel image of the Orion Constellation taken by Matt Harbison.

For this particular study, scientists looked at a subsample of 70,000 stars from the above image. It had been previously believed that the stars in the bulge were born in two separate “waves” early in the history of the galaxy, but thanks to data gleaned from the study, now scientists think that a vast majority were formed at about the same time nearly 10 billion years ago.

According to Nasa, the researchers are looking into the possibility of measuring stellar distances to make a more accurate 3D map of the bulge. They also plan to seek correlations between their metallicity measurements and stellar orbits. That investigation could locate “flocks” of stars with similar orbits, which could be the remains of disrupted dwarf galaxies or identify signs of accretion like stars orbiting opposite the galaxy’s rotation.

(Via Hubblesite and SyFy)

NASA Turns Space Photos Into Music

NASA has a new project that turns space photos into sounds. Using sonification, images obtained from telescopes are turned into “music” that sounds like what you’d hear when your operating system boots up.

The creative project is being carried out by scientists at NASA’s Chandra X-ray Observatory.

“Telescopes give us a chance to see what the Galactic Center looks like in different types of light,” NASA writes. “By translating the inherently digital data (in the form of ones and zeroes) captured by telescopes in space into images, astronomers create visual representations that would otherwise be invisible to us.

“But what about experiencing these data with other senses like hearing?”

Sonification is the process of translating data into sound. Starting on the left side of images and moving toward the right, NASA’s sonification system reads in the vertical rows of pixels and creates sounds that represent the position and brightness of things seen.

“The light of objects located towards the top of the image are heard as higher pitches while the intensity of the light controls the volume,” NASA says regarding the Milky Way photo and music in the 1-minute video above. “Stars and compact sources are converted to individual notes while extended clouds of gas and dust produce an evolving drone.

“The crescendo happens when we reach the bright region to the lower right of the image. This is where the 4-million-solar-mass supermassive black hole at the center of the Galaxy, known as Sagittarius A* (A-star), resides, and where the clouds of gas and dust are the brightest.”

Here are the sounds created from other photos:

Now NASA just needs to release these songs as galactic ringtones for our smartphones.

(via NASA via Laughing Squid)

You Can Shoot 96MP Pixel-Shift Astro Photos with the Panasonic Lumix S5

The Panasonic Lumix S5 has just been released in New Zealand, and I received mine a few days ago. Last night, with clear skies, I took it to the south coast of Wellington, New Zealand, to see what the new advances in High Resolution mode included in the S5 could bring.

This mode takes 8 images, shifting the sensor between each image a tiny amount, to create a final image with four times the pixels of a single image (96 megapixels compared with the sensor’s native 24 megapixels) and with lower noise than a single frame.

In the past High Resolution mode (on the S1 or S1R for example) has allowed for ISO up to 3200 and exposure duration up to 1 second – not really conducive to Milky Way imaging. However the Lumix S5 extends that limit significantly…

The S5 allows for High Resolution mode with ISO up to 3200 and duration up to 8 seconds per image, so I started imaging the Milky Way at 8 seconds (with a Sigma 14-24mm f/2.8 DG DN lens at f/2.8). That led to some star trails in the final image further away from the celestial south pole, so I backed the exposure time down to 2.5 seconds and tried again.

After processing the resulting image with Affinity Photo (which can read the RAW files; Adobe Camera Raw can’t yet, though I’m sure an update is close), I was very happy with the result.

I did have to push the exposure a bit more than three stops given the short exposure time per image, but because the final image is automatically generated from a combination of 8 individual images the final result still had reasonable noise characteristics — certainly very useable.

100-megapixel (well, nearly) astro imaging is a reality with the Lumix S5.

Other than High Resolution mode, for single-shot imaging the sensor is very nice and clean at high ISOs. I’m a very happy S5 owner today.


About the author: Jonathan Usher is a landscape photographer based in Wellington, New Zealand. The opinions expressed in this article are solely those of the author. You can find more of Usher’s work on his website.