Quick Overview

Use AstroScope to search, record and explore a user defined region in the sky centred on a given position or object name. Enter either a known astronomical object name or specify RA, DEC in sexagesimal or degree format along with search radius or area. In the example below, the object name "M101" is recognised automatically as a known Simbad object and the catalogued coordinates for M101 are resolved. The search radius is input as 0.01 degrees.

Search archives

All registered datasets are then queried including Catalogue, Image and Spectral archives. For this particular search region, only catalogue and image records are found and displayed in the default radial view as shown. Hover your mouse on a particular service node in order to see a basic description of as supplied by the given data centre as to what is contained in a given service appear as a tooltip. The SDSS DR4 image archive at JHU is shown in the example below, i.e. the search region overlaps with at least one publically available image contained in SDSS DR4:

The Services tab shown below records VO available services as they are queried in a list with number of records found for given search including links to further information about the service and any access errors encountered, e.g. if a particular service is registered but not currently available ("Message" column). Click on the "Service" column header to order the list in alphabetical order to search for a particular service. The "Results" column lists the number of records found in a particular archive for the given search area.

Visualisation

 
As results are found they are displayed graphically in two different visualisations based on navigable clusters of nodes. For the default "Radial" view a 'click of the mouse (leftbutton)' is needed to browse up and down the various nodes as follows:

                            all images, catalogues or spectra (see 1st screenshot above)

                                                                         |

                                                              one of above only

                                                                         |

                   offset in arcsecs or degrees (user may toggle) from centre of search region

                                                                         |

                                          position on sky (sexagesimal or degrees)

                                                                         |

                      image, spectrum or catalogue record including format (where available).

The 'Hyperbolic' view shown below visualises the same results in a tree state where all the nodes described may be visible and a click of the mouse re-centers on a selected node within a tree. In the example shown below the user has hovered on an individual 2XMM pre-release catalogue record in order to see further details including position and unique ID and energy dependent fluxes for the object as made available by the given archive.

If a search is not complete it may be stopped at any time using the "Halt" button and the user may jump back to the top visualisation level as needed using the "Go to Top" button. This is independent of which visualisation is being used.

Selecting Records

A double mouse click on a particular record or group of records turns them yellow and selects them in order to save to MySpace or local disk by then left clicking the "Save" icon.  Click  the "Clear Selection" button to unselect again. Below the user has chosen all SDSS-DR4 images.

Pass records directly to VO Helper Applications

In addition, you may pass the selected images, spectra or catalogue records to interoperating VO tools such as those linked from the HelperApplications tab of the workbench. The application icons available on selecting a service are highlighted in the "Process" window as seen below. In this example, a number of entries in the XMM-Newton serendipitous survey catalogue are selected and the user has then clicked on the TopCat logo in AstroScope to pass the records directly into that catalogue visualisation and manipulation tool.

See below for further details of individual buttons and functionality.

Button Action

• Submit -- starts the processing of the query based on the position/object and region size.
• Save -- Only enabled when selected data is present. Brings up a box allowing you to save to myspace or your local computer. You MUST choose a directory this is because of multiple files are saved. Hence unique file names will be saved in the appropriate directory.
• Go to Top -- results in bringing in the focus of the top node 'Search Results'. Currently only for the 'Radial' view.

Graphical Actions

• Single Click (leftmousebutton) -- results in re-centering the desired node to the center of the graph. In the 'Radial' window it will expand any information/children of that node.
• Double Click (leftmousebutton) -- results in selection of that node and all its children. You may select the 'Search Results' node (the top) if you desire everything.
• Left Mouse Button (Dragged/Hold Down) -- results in panning around the graph, this may be desirable on a lot of results.
• Right Mouse Button (Dragged/Hold Down) -- results in zooming the display. Hold Down the right mouse button and scroll up for zooming in (enlarge), scroll down for zooming out.

by JonathanTedds — last modified 2006-11-05