A GPS System for Cosmic Images

Imagine getting a picture of some random patch of the Earth. This picture has some features on it - maybe a mountain or a river or even a city - but from the altitude it was taken, you can't be exactly sure what's what. And then imagine if someone asked you to place it exactly where it should lie on the Earth. Really hard, right?
Google Earth
It's New Hampshire - USA

Well, of course, it gets a lot easier if someone were to give you the exact longitude and latitude. While this seems like an obvious thing to do, it's not so simple for astronomical images. When astronomers create their images for scientific purposes, these images retain certain coordinate information - like longitude and latitude - but for space. Unfortunately, when these images get processed further to make them attractive for the public, this information gets stripped out. In other words, we're back to having no clue where this image matches up with anything else.

In the past several years, however, there’s been a big push to change that. Because, after all, we all want to know where we’re looking in the Universe when we see these beautiful images. The Virtual Astronomy Metadata Project (VAMP) was created to do just that.

So along with Spitzer, Hubble, and many, many other observatories and telescopes - both in space and on the ground - we've been working very hard to encode Chandra images with so-called Astronomy Visualization Metadata, or AVM. Tagging astronomical images with AVM ensures that key information - such as the image description, the type of object it is, the location, and more -- stays linked to the image as it travels throughout the Internet. By keeping content embedded with the imagery, the outreach potential of each image released with AVM is increased dramatically.

Without AVM, it is virtually impossible to place publicly released astronomical images in their proper place on the night sky. With AVM information, however, these images can be imported and used in a host of new and exciting technologies. For example, Microsoft's Worldwide Telescope and the Google's Sky project both feature Chandra images because of this information. Likewise, digital planetariums can directly import Chandra images into their shows and other exhibits thanks to AVM. Such online services like Flickr, Smithsonian Photography Initiative, and Wikisky are able to automatically incorporate images from Chandra because they have this information embedded into their electronic DNA.
Chandra Images
In short, this crucial, yet largely invisible, technology is allowing Chandra images - perhaps a bit ironically - to be shared, admired, and seen by millions of people.

-Megan Watzke, CXC

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