Blueshift - February 17, 2009

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Maggie Masetti: Hello, and welcome to Blueshift, the podcast brought
to you from NASA's Goddard Space Flight Center. This is our
February the 17th 2009 edition, and I'm Maggie Masetti, your
host. We try to bring the universe closer to you in each of our
episodes, but we aren't alone in doing this. We have lots of help
from services like Google Sky and World-Wide Telescope, which
allow you to call up the whole universe on your home
computer. But do you ever wonder where they get all these images
from? Do they launch their own telescopes to take these images,
or do they use existing data? That's what we'll hear about today
when we talk with Tom McGlynn, an astronomer here at Goddard, and
the creator of SkyView. SkyView is essentially a virtual
observatory that allows a user, which could be anyone from a
professional astronomer to an interested amateur on their home
computer, to view any part of the sky at wavelengths ranging from
radio to gamma rays. SkyView's capability comes from it being
essentially a repository of astronomical data from many different
missions and surveys. Now, here's Tom to tell us a little bit
more about how SkyView came to be.

Tom McGlynn: I realized that there were all these all-sky surveys that
were coming on-line, and they were being placed in lots of different
archives, and they all had very difficult, customized mechanisms for
getting access to them. And I said it would really be great if there
was one place you could go, and say I'm interested in this position on
the sky, and get an image of it, not just in the optical, but in gamma
rays, or in radio data, or ultraviolet data, and be able to compare
what the sky looks like in all different wavelengths. SkyView has data
ranging from 30 megahertz in the radio all the way up to the EGRET
data, I think it's a range of something like 18 orders of magnitude in
frequency. The goal of SkyView has always been to make it possible to
get to the data in a standard way. The goal is to get the data to the
people. With SkyView for example, if you want to get ROSAT data, which
is an X-ray survey, you just go in, click on ROSAT, and put in your
position, and now you have instantly an X-ray image of the sky. We've
done about 3 1/2 million requests last year, so that's actually 3 1/2
million images generated. There's a total of close to 20 terabytes of
astronomical data that is queryable through SkyView.

Maggie: All you need to explore astronomical objects with SkyView
is a Web browser. However there are other ways now to access SkyView's
data archive. Remember we mentioned Google Sky and World-Wide
Telescope at the beginning of this podcast? Well, guess what?
SkyView's huge database has been used as the backend to both of
them. Using World-Wide Telescope or Google Sky as the interface, your
computer can function as a virtual telescope, allowing you to view all
sorts of astronomical data on your computer screen. Here's Tom again
to tell us how SkyView has been integrated into both of these
services.

Tom: Something over 15 or 20 of the surveys available in
World-Wide Telescope are gotten through SkyView, and we are working
with Google Sky to provide many of the data sets for them as
well. Google and World-Wide Telescope do an incredible job of
providing a user interface to data. You can zoom around and pan and
really, it's just fascinating to just play with those tools. But they
have to get the data into a standardized format first to actually be
able to use it. And SkyView helps them bridge that link. So we take
the data from the actual imagery, and we can actually transform it
into any format that Google Sky or World-Wide Telescope would like to
use as their inputs.

Maggie: Tom told us about some of the other applications and uses
of SkyView, some of them a little bit unusual.

Tom: We have data from the Near-Earth Asteroid Tracking System
which is, I think it's now 700,000 images that were taken with the
specific purpose of trying to find asteroids that are going to destroy
the Earth. And they didn't find any yet. If you're taking an astronomy
course and you hear about an object, you can go in and you can take a
look. And one of the things I find fascinating in SkyView is to just
look at large regions of the sky in different wavebands. The universe
looks very different when you look at it in the infrared sky as when
you look at it in the X-ray sky, as when you look at it in the
optical. And there's actually just these beautiful pictures that you
can see. There's structure in all of these wavebands, so you might be
seeing the gas in our galaxy. One of the real joys in working with
SkyView is just the ability to play.

Maggie: So SKyView really helps to bring the universe home to
people. It's like picking up an atlas and seeing this whole compendium
of images. Without SkyView that would be a lot harder, and it would
take you a lot more effort to go and find them.

Tom: There is no service that has the... There's services that
provide individual surveys, but there are essentially no services
which provide everything, again with this enormous wavelength
coverage. And all using exactly the same interface. It's really just,
type "position", "survey", click on the survey, and you're done.

Maggie: SkyView really is a one-stop shop for people wanting to look
at data from a lot of different surveys in a lot of different
wavelengths. In this era of modern astronomy, the universe is just a
click away on your computer screen. We've really come a long way in
400 years, which makes me wonder what Galileo would have thought of
this if he were here today. If you'd like to try SkyView, check out
our web site at universe.nasa.gov/blueshift, and we'll have
information for you on where to find it. Feel free to drop us a line
on our feedback form, and let us know if you're enjoying the new
format of our podcast. You can also feel free to let us know what
you'd like to hear about next time. Please join us again in a couple
of weeks for another episode, in which we bring another piece of the
universe closer to you. This is Maggie Masetti for Blueshift.

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