What is the National Virtual Observatory?

The National Virtual Observatory (NVO) is a new research project whose goal is to make all astronomy data in the world quickly and easily accessible by anyone. The NVO was created to solve two difficult problems that astronomers currently face in doing their research. This document describes what the problems are and how the NVO will solve them.

What happens to old data?
How do scientists get data from all wavelengths of the electromagnetic spectrum?
Solution: the NVO

Problem #1: Getting New Results from Old Data

For thousands of years, astronomers have been studying the sky. They started looking at the sky with their eyes, creating star charts and maps. In the 1600s, astronomers began using telescopes, allowing them to see many more stars and galaxies. Over the past several hundred years, telescopes have gotten more and more powerful, allowing astronomers to see millions more stars and galaxies. When computers were invented, astronomers began to use computers to control their telescopes.

Today, telescopes are so powerful that they can see thousands or millions of sky objects every night. Sophisticated computer programs identify and analyze the objects seen in the telescope images. These powerful new computer-equipped telescopes are making observations faster than astronomers can keep up with them.

Today, when an astronomer uses a telescope to make an observation, she studies the new observation carefully, seeing how it fits with other observations she has made already. The new observation then goes into a data archive.

Of course, her new observation is useful not only to her; other astronomers could potentially learn a great deal about the universe by studying her observation, and comparing them to other observations that they have made. But the other astronomers are busy with their own research observations – they probably do not even know that her observation exists. So the observation sits in the data archive, waiting to be rediscovered and reinterpreted by another astronomer.

In this way, lots of useful astronomy data ends up hidden in data archives, with the potential to be rediscovered and to answer important questions about the universe. Astronomers need a way to easily search through archived data, quickly find the data that they are interested in, and analyze the data in new and exciting ways.

Problem #2: Getting Data from All Wavelengths

Over the past several decades, astronomers have built telescopes to see the sky in other wavelengths of the electromagnetic spectrum: radio waves, infrared light, ultraviolet light, x-rays, and gamma rays. Just like visible-light telescopes, these telescopes in other wavelengths are producing huge volumes of data ready to be studied by ambitious astronomers.

Although these telescopes look at the sky in many different wavelengths of light, they are all looking at the same sky. Many sky objects have images taken in nearly all wavelengths of light. Each image shows different features of the object being studied, so astronomers would like to combine all the images to get a complete picture of the object.

But the images were taken by different telescopes at different times, organized by different groups of astronomers in different places. In the past, combining all these images into a single picture of the object was time-consuming and required lots of specific knowledge about how the images were taken. Astronomers need a way to seamlessly combine images and data from many different wavelengths of light to form a single coherent picture of a sky object.

Solution: The NVO

The National Virtual Observatory (NVO) was created to give astronomers the tools they need to do their research, giving them immediate access to all astronomy data ever taken. With NVO, astronomers will explore data that others have already collected, finding new uses and new discoveries in existing data. They will easily combine data from many wavelengths, enabling them to understand objects as seen in all wavelengths of light. The NVO will enable astronomers to do a new type of research that, combined with traditional telescope observations, will lead to many new and interesting discoveries.

The NVO will be like an Internet search engine for astronomy data, available not only to astronomers, but to the general public. You can use the NVO’s web interfaces to request data – for example, to display all Hubble space telescope pictures of the Andromeda galaxy, or to display all bright galaxies that have images in both visible and ultraviolet light.

For the past three years, NVO scientists have been working to develop the standards to allow data to be shared across the world. Now that this behind-the-scenes work of defining standards has been done, NVO scientists are building tools to access data.