VO Services
XML Web Services are essentially library modules or API that live on the Web. You can access the published methods by making so called SOAP requests. Because of the underlying technology (XML, SOAP, WSDL, etc.) Web Services are inherently interoperable. In other words, you can use them regardless of what your favourite platform and operating system are. Freely downloadable toolkits, such as Microsoft's .Net Framework and Apache's Axis for Java, make the integration of Web Services seamless with your code. Many of the services listed here come with short descriptions on how to get started. For more details, please check out the help page!
Below is a suite of services developed for the Virtual Observatory
Authors: Tamás Budavári, László Dobos (JHU)
There is much more to astronomical observations than just source catalogs. For example, when working with multiple observations at different wavelengths, knowing their precise coverages is just as important, e.g. to look for dropouts, and can be very difficult in case of the most significant observations that are often the most complex, as well. This functionality has been missing almost entirely from the toolbox of many astronomers until today.
We present high-level user and Web services for dealing with astronomical survey geometry of arbitrary complexity. Based on our high-performance spherical library, we built an online public repository of footprints preloaded with the coverage of some of the most widely used datasets today including the Sloan Digital Sky Survey (SDSS), the Galaxy Evolution Explorer (GALEX) and the Hubble Space Telescope (HST) exposures. We publish a Web based toolkit that enables advanced spatial searches for regions of interest on the sky, Boolean operations on selected footprints (union, intersection), on-the-fly visualization, and exact area computation. We also provide an easy-to-use interactive footprint editor, as well as a simple upload facility. The results of the searches and region manipulations can be saved and published on the footprint server or downloaded in various formats including ASCII and the VO compliant Space-Time Coordinate (STC) region representation.
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Authors: László Dobos, Tamás Budavári (JHU)
We present easy-to-use web applications and Web Services to search, plot and manage spectral energy distributions and filter profiles. We provide keyword search, advanced query forms and SQL interfaces to select spectra or bandpasses that may be retrieved in a variety of formats including XML, VOTable and ASCII. All SDSS DR1 spectra had been loaded into a database as well as the entire 2dF catalog that adds up to almost half million SEDs but registered users can upload their own data making it available for the rest of the community and are free to modify or delete them at any time. Scientific services allow to build rest-frame composite spectra out of selected spectra. The bandpass database has a growing collection of photometric filters and the same search interfaces. Using the spectrum and filter profile core services, we plan to build higher level services to help astronomers create color-color diagrams, simulated catalogs and estimate distances to extragalactic objects.
Authors: Gretchen Greene (STScI), William O'Mullane (JHU)
As part of the NVO framework development initiative a prototype Astronomical Registry was designed for serving resource metadata across the internet to the world community. While this registry incorporates many VO standard Cone Search and Simple Image Access (SIA) services it provides mechanisms for publishing custom archive services with associated metadata as well. The registry is mirrored at two sites, Space Telescope Science Institute and Johns Hopkins University, and additionally harvests resources at Caltech and NCSA OAI repositories. Web services and forms were implemented for independent higher level application integration with the registry such as the NASA Data Inventory Service (DIS). These interface methods provide fundamental add, edit, remove features and include standard SQL query support. This registry is built with .NET technology integrated with MS SQL Server Database, IIS Web server, and C# product code.
Authors: Tamás Budavári (JHU)
This an XML Web Services wrapper for the official Nasa Extragalactic Database (NED) at tcp://ned.ipac.caltech.edu:10011. It supports SOAP, HttpGet and HttpPost protocols and returns the results in XML format. The data structures are true translations of the C structs of the original client library by Xiuqin Wu (1993). Example of usage:
NED ned = new NED(); ObjInfo o = ned.ObjByName("m101");
This is a very simple service that returns various cosmological distance measures, e.g. luminosity distance, for a given redshift (z) in a LCDM cosmology. Example of usage:
Distance dist = new Distance(); float z=0.1, h=0.7, m=0.3, l=0.7; float r = dist.Luminosity(z,h,m,l);
Authors: Maria Nieto-Santisteban, Alex Szalay (JHU) and Jim Gray (Microsoft)
ImgCutout is a web application that enables professional astronomers and the general public to interactively visualize and explore large, complex astronomical data sets. The application consists of a web interface that calls a web service, which accesses SkyServer, a 1TB SQLServer database containing catalog data for 100 million objects, spectra and images from the Sloan Digital Sky Survey. ImgCutout builds, in real time, color mosaic-images of user-selected regions of the sky, and overlays additional information about astronomical and spatial objects in the database including: boundaries of survey fields and aperture plates, outlines of individual objects and data quality masks, in addition to locations of photometric and spectroscopic objects. The tool can search for lists of known objects, provide detailed information about selected objects, and formulate new database queries.
Authors: Tamás Budavári, Nolan Li, Wil O'Mullane, Vivek Haridas, Ani Thakar (JHU)
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Authors: André Schaaff (CDS)
This XML Web Service provides astronomical coordinate translation. This example shows the result for 04 13 44.4 +33 51 16. (J2000.0),
convert(10.0, 20.0, 15.0, 5)
This XML Web Service provides access to VizieR Catalogues. The example below returns the associated VizieR information in VOTable format,
cataloguesData("M31", 10.0, "arcmin", "Dixon")
This XML Web Service: (1) resolves a UCD tag, (2) gives the whole UCD (tag and description) list and (3) gives the list of UCDs contained in a given catalog. The example shows the result for Johnson magnitude V (JHN),
resolveUCD("PHOT_JHN_V")
