What Does 1.5 Billion Pixels Look Like?

Jan 18, 2015

Andro_aThe Andromeda galaxy contains over 100 million stars and “spans more than 40,000” light years.

NASA has taken 411 Hubble Space Telescope pictures and created a mosaic of Andromeda, making a 1.5 billion pixel image, which they released on January 5, 2015.

It’s the biggest image ever taken of the Andromeda galaxy.

Below is a depiction of seeing Andromeda from Earth. It’s the disc-shaped image high above the mountain top and to the right:



Below is an image of the whole galaxy:

m31_comolli_960 states…

The Panchromatic Hubble Andromeda Treasury is a Hubble Space Telescope Multi-cycle program to map roughly a third of M31’s star forming disk, using 6 filters covering from the ultraviolet through the near infrared.  With HST’s resolution and sensitivity, the disk of M31 is resolved into more than 100 million stars, enabling a wide range of scientific endeavors.

The diagram below, from the same website, illustrates the area of Andromeda that was created the unique image:



PHAT celebrates Hubble’s 25th year! As part of the yearlong celebration, NASA and ESA are releasing a beautiful mosaic of the optical data from PHAT.  This mosaic, done in collaboration with astrophotographer Robert Gendler, is the largest Hubble image ever assembled.  Not only does it show the overview of Andromeda’s star forming disk, but at full resolution, it also shows hundreds of millions of the stars that comprise the galaxy. (


The resulting “photograph”:



PHAT tells us that the image above consists of 104,014 x 37,157 pixels. Exposure time: 936 hours (39 days, 5.5 weeks, and 1.25 months). Number of exposures: 7398.

The first image was taken on July 12, 2010, and the last image was on October 12, 2013.

Two thousand seven hundred fifty-three star clusters were identified and 117 million stars were identified.

To “play” with this image by moving from area to area, then zooming in and out, visit

The bright light in the lower, almost middle of the image above may be seen in the series below as we zoomed in closer and closer:



The box in the upper right hand corner is the whole slice of Andromeda.





The closest image:



Can you make out the tiny, tiny red dot in the upper part of the image below, just off center to the left?



This is as close as we could get…



An image of the pixels seen as one zooms in:





The closest we could get to this section of the galaxy…



Another section, yellow this time:



The closest we could get:



Yes, we got a bit carried away. A post that should have taken no more than twenty minutes, took much longer than an hour as we researched and traveled from site to site, and then played with the interactive image. Extremely addictive.

We shall end with an image of the folks responsible for this incredible, mind-blowing fun and knowledge…


Heddy Arab, Eric Bell, Lori Beerman, Luciana Bianchi, Martha Boyer, Nelson Caldwell, Julianne Dalcanton (PI), Andy Dolphin, Hui Dong, Claire Dorman, Morgan Fouesneau, Karrie Gilbert, Leo Girardi, Stephanie Gogarten, Karl Gordon, Dimitrios Gouliermis, Raja Guhathakurta, Paul Hodge, Jon Holtzman, Kirsten Howley, Cliff Johnson, Jason Kalirai, Chris Kochanek, Dustin Lang, Soeren Larsen, Tod Lauer, Adam Leroy, Alexia Lewis, Jason Melbourne, Antonela Monachesi, Knut Olsen, Hans-Walter Rix, Keith Rosema, Phil Rosenfield, Abi Saha, Izaskun San Roman, Ata Sarajedini, Anil Seth, Jacob Simones, Evan Skillman, Kris Stanek, Rachel Wagner-Kaiser, Dan Weisz , Ben Williams.






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