Rick, the SkyServer is a website we built to make it easy for professional and armature astronomers to access the terabytes of data gathered by the Sloan Digital Sky Survey – the SDSS. It was largely built by Professor Alex Szalay and his students at Johns Hopkins university I helped with some database and web service issues. My particular interest is in dealing with the database problems, and exploring the “online-science” issues you were just describing.

You can see a picture of the telescope in this web page. The survey is about half done now and we have about 100M objects, .5M spectra, 10 TB raw, and 1 TB of catalog data.

The SkyServer has been on the internet for 2 years now and just got its second data release – and a new look designed for us by the Microsoft Research Next Media group. All the catalog data and some of the pixel data are in an SQL Server database. All this data is available to everyone everywhere via this website.

Since this is one of the world’s best telescopes, it is a GREAT Since this is one of the world’s best telescopes, it is a GREAT! way to teach astronomy. Jordon Raddick has built about 150 hours of online instruction around the database. There are classes at all levels.

Using this data, students can redo Hubble’s measurements and discover Hubble’s constant for themselves. This teaches astronomy and computational science at the same time. There are dozens of other interactive lessons using the data. I have learned a lot by doing the lessons. This is some of the best astronomy data in the world, so students have the potential to do new science with it.

Lets drill into the data by using some of the visual tools that Alex and I built.

Lets use the Navigate tool which is my first web service.

What’s going on here is that the web service is pulling images from the database, rotating them so north is up, stretching them and painting them on the canvas – using GDI+. There is a lot of Jpeg going on too. We can invert the image… click Get outlines…. Click And a label … click And zoom out … click click…. At each of these steps the web service is doing some very interesting spatial database searching. Notice I can point to a different object and get it’s attributes and cutout. When I do that, the browser is sending an x,y to Baltimore. The IIS server in Baltimore is converting that to lat, lon, zoom and calling a local web service. That web service is doing a spatial database search, pulling data and images from the database and producing the resulting image.

We can also do this for sets of objects Each of these cutouts is a web service call

And for the very brave, you can write your own sql query and find your own sets.

Here are the 10 high-redshift objects in the database. Lets look at the brightest one

We have just moved from Pixel space to record space. This is a summary of the thousand things we know about this particular object.

Here is a cartoon of its spectrogram showing the spectral lines

And here are those same lines as database records. The astronomers do datamining on these kinds of things. As I said we have a 3 billion record database underneath all this.

The SkyServer design has been cloned by several other observatories. The People at Cal Tech have the Digital Sky server. The folks in Cambridge England have put their data online. In all there are about 10 archives online. Alex’s students at JHU have integrated these archives together with SkyQuery.Net. I do not have time to tell you much about SkyQuery, but just let me show you an example of combining data from Sloan at Baltimore and Isaac Newton Telescope data from Cambridge England. I am going to use a sample query. This is all done with .NET datasets and XML and WSDL.

And here is the answer to that query And here is the answer to that query. It combines data from both sides of the Atlantic. The astronomers are really excited about this – It was 4 nodes a few months ago, it has now grown to 10 archives and there is a LOT of interest in extending it. It is the start of the world-wide telescope.

So, how hard was this? It was relatively easy. Mostly Alex Szalay and his students have done all of this – say 5 people in all. And they all have night- jobs -- they are astronomers. If you want to see how it works all the code is public, you can download it from SkyServer.Org. A 1GB subset of the SQL database is there and the website is there and the web service is there. All you need is WinXP and SQL 2K. All the spatial database search is there, all the datamining stuff is there, and a bunch of research reports are there.

Just to give you as sense of it, let me show you how I work with it. I have it here on my laptop Lets debug that cutout service we have been using all during this demo. First I should mention that, Maria Nieto-Santisteban of JHU took the toy implementation I had and added most of the cool astronmy features and cleaned up my code. So, we are really looking at Maria’s code here. To give you the sense of how it works, lets start without debugging.

That worked, now lets start with debugging.

Wow, and here I am stepping through the ASP page, and then to Maria’s C# code.

And that’s why I love Visual Studio, this is really easy. Well, as you can see, I could go on for hours talking about this, But, you can download all these programs and look at them for yourself.