VizieR Search Help

This help page describes the form elements available for searching for VizieR catalogs. Several qualifiers can be used to locate available catalogs. Once a particular catalog is found, additional qualifiers can be used to query the catalog entries and/or cross correlate the results with MAST mission catalogs.

When searching VizieR catalogs (i.e. without cross correlating with MAST mission), users have the option of displaying catalog results graphically with VOPlot. VOPlot is a JAVA applet requiring a Java plgin to view in a browser. (Note a javascript-related bug was discovered which prevents VOPlot from running on Mac computers and is currently being investigated.)

Cross Correlations - When cross correlating MAST missions using vizier search results, the VizieR search tool retrieves the coordinates for each returned VizieR entry and uses them to perform a cone search with a given search radii for each requested MAST mission. The search results page will list each set of coordinates used and, if found, the related MAST entries. Vizier catalogs without equatorial coordinates can not be used for cross correlations.

Catalog Search Form

Catalog Name

On the catalog search form, the Catalogues can be designated

• by their usual acronym or abbreviation like NGC, HIP, USNO2, etc... (full list of acronyms known in VizieR)
• by their CDS/ADC designation like I/239 or 1239 assigned to the Hipparcos catalogues, or J/A+A/275/101 for the tables associated to the publication in A&A 275, 101 (full list of Designations known in VizieR). The designation may specify a unique table, like VII/224/table2 which represents the table of confirmed, probable or possible BL Lac objects in Ve'ron and Ve'ron compilation of quasars (10th Ed., 2001). (Note on the results page, the Vizier table names will be listed.)

Note that

• several catalogues can be entered, separated by blanks or commas, like Tycho-2,USNO2 for the Tycho-2 and the USNO-A2 catalogues.
• the * (asterisk) can be used as wild character, and you may for example get all catalogues of the IX category (high-energy catalogues) by entering IX/*

Mission Name

Name of mission. Chosse from those listed in the pull-down menu.

Selection by word or keyword

You may enter one or several words which are simultaneously found in a short description of the catalogue, which includes author's names, the title, and a short summary. For instance, typing "cfa redshift" will locate catalogues quoting these two words in any order. Note that

• words made of 1 or 2 letters are normally ignored (there are a few exceptions, like IR or UV)
• only the first 7 characters of a word are significant;
• common words (like and, are, etc) are ignored
• the plural in words should be avoided (use galaxy, not galaxies)

Astronomical Terms

Various astronomy-oriented terms for selecting VizieR catalogs derived from the controlled ADC_Keywords existing in every catalog ReadMe file. These ADC_Keywords are not taken into account in the words selection option, however, if the keyword you want is not included in the pulldown menu, try entering it as a keyword search (e.g., Herbig-Haro objects).

Target Name

Specifying a target name restricts the choices of catalogues to those containing of at least one object at a distance of up to 1(?) arcmin from the actual target position. Note: A wavelength range or mission name must be specified with the target name!

Wavelength Region

Restricts search to catalogues within the specified wavelength region.

VizierR Server

Selects which Vizier mirror site to use for submitting search request. Normally the CFA site should be used, but another site may be selected if CFA is down. Also, for recent catalogs or coding changes, it may be useful to search the home site at CDS in Strasbourg, France.

Catalog Search Results Page

User Option

You may now search on any column in the mission database. Select the field you wish to search on and type in the qualification. You may find the valid range of values by clicking on the field name. NOTE only fields which are not already included on the search form should be selected. Specifying search criteria for a field that is listed in BOTH the form and in the User Option field, may cause either the query to fail or return unexpected results.

Output Columns

This form element allows one to choose the columns to be displayed and their order, for the search results. A set of columns that are commonly requested has been chosen as a default.

You remove output columns by highlighting the column to be removed and then clicking on the remove button to the right of the output columns list.

You may determine the order of columns by highlighting a column and then clicking on the up or down buttons to the right of the list of chosen output columns.

You may also add a column to the list. Select the desired column from the pull down menu beneath the list of chosen output columns, then click the add button. The column will be added to the bottom of the output column list.

Note the output column form element has its own reset button to restore the list of output columns to the values initially displayed when the page was drawn. The reset button at the top of the form is used to reset the other form elements. Clicking the "clear form" button however can be used to restore the original default values.

Sort output by:

Choose how you want the output rows sorted (by default). You can select up to three fields to sort on. The rows will be sorted in the order of the first sort field; if two rows have the same sort field, they will be sorted in order of the second sort field, and so on.

For each field, you can select that the rows be sorted in reverse order on that field by selecting the reverse checkbox. For example, you can sort the rows with the most recent observations first by selecting Observation Date for the first sort field and selecting the reverse checkbox next to it.

Note that the latest search scripts also allow users to sort results based on any of the displayed fields, simply by clicking on the column names at the top of the search results table. Clicking a second time will sort results in descending order. This sorting feature however does require javascript to be turned on.

Display Coordinates

Specifies whether coordinates are output in decimal or sexigesimal format. Decimal coordinates will have 5 significant figures to the right of the decimal pont. Sexigesimal format is used by default.

Maximum Records

This value specifies the maximum number of rows returned in a single query. For the standard mission search forms, the current default is 1,001, but values from 1 to 15,001 are allowed. For the file upload forms in which multiple targets, data ID's, or coordinates can be specified, the default is set to 20 rows per file entry, with allowed values ranging from 1 to 500.

Note when displayed as HTML, the latest search scripts will display 50 records per page. Links to the additional pages are shown on the results page. This paging feature however does require javascript to be turned on.

When queries are submitted as a web service, the default number of rows returned is 2,000, but any value is allowed when max_rows is specified as a query parameter. (See the MAST Web services page for more information.)

Records per page

This parameter controls the number of records displayed per web page. By default, 50 rows or records are displayed per HTML page. Therefore if 200 records are returned, links to 4 pages will be displayed at the top and bottom of the results table. Selecting 100 would display 100 records and links to 2 pages. The paging feature however uses javascript, so if javascript is turned off, paging won't work and only the rows shown on the first page can be displayed. This is one reason why increasing the default value may be helpful. The current limit is 500 rows per page. Note this value is ignored when output formats other than HTML are selected.

Show SQL Query

Select this checkbox if you want to see the SQL query that the IUE Search engine constructs from your query qualifications. The query will be shown at the end of the search results.

SQL (Standard Query Language, pronounced either "ess cue ell" or "sequel") is a language used used by most relational database systems for retrieving information from database tables. The sarch script takes your search specifications and converts them to an SQL query to run on our database. Viewing the generated query is often useful for debugging, and may also be useful for SQL-literate users who want to see what logic was used in the query. (In fact, this may be useful for most people, since SQL is pretty easy to understand.)

Make Rows Distinct

Select this checkbox if you want to have a set of distinct rows displayed. This is useful if you would like to see a distinct list of objects with certain criteria e.g. all the objects within an IUE or FUSE object class. In this case, one would limit all but the "Target Name" (or RA and Dec); this is done with the "Remove" button in the Output Columns window. This action permits a selection only on unique targets names (or coordinates) that have been observed by the satellite for the object class given. (Hint: be sure to keep the "Maximum Records" number large enough for the length of your anticipated list!) Also note that columns such as RA, Dec and Magnitude were frequently defined by the observer and often have different values for the same target name. If columns such as these are chosen as output columns, there will often be more than one row listed per object name.

Output Format

You may choose any of the following formats for displaying/storing search results. If you are using a browser (e.g., Firefox, etc) to submit a query from a MAST web form, the formats labelled "File: ..." offer a way to download results directly to your local computer. Choose any of the other format options if you want to display the results in the browser, or if you are submitting the request from a program (see MAST web services).

• HTML_Table (default) - results returned as a standard HTML table including various links for retrieving data, displaying previews, literature references, plotting spectra, etc.
• File: Excel_Spreadsheet - results are stored as an Excel spreadsheet file. (Note: assumes users computer/browser provides support for Excel-format files). The default file name when downloaded is "mission"_search.xls where "mission" is the mission name (e.g., fuse_search.xls).
• VOTable - an XML format adopted by the Virtual Observatory (VO) project and displayed in the user's browser. Note coordinates in VOTable format are always in decimal degrees rather than sexigesimal format. For searches returning results from more than one mission and/or target, multiple "resource" tags are created. Searches with a radius of 0 will return a VOTable file listing the output fields for that particular mission/catalog. (For more information on the XML file format, see VOTable documentation.)
• Comma-separated values - a simple ASCII array containing column headings followed by rows of comma-separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries.
• Space-separated values - a simple ASCII array containing column headings followed by rows of space-separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries. Note users may want to select coordinates in decimal rather than sexigesimal format to maintain the correspondence between column headings and entries although some column headings may contain blanks as well. (Semi-colons or commas are probably safer delimiters.)
• Semi-colon separated values - a simple ASCII array containing column headings followed by rows of semi-colon separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries.
• File: comma-separated values - a simple ASCII text file containing column headings followed by rows of comma-separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries. Rather than being displayed in the browser, the results are directly downloaded to the users computer using the file name "mission"_search.txt where "mission" is the mission name (e.g., hst_search.txt). Depending on the browser settings, the user may be prompted for a file location before the file is downloaded.
• File: Space-separated values - a simple ASCII text file containing column headings followed by rows of space-separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries. Rather than being displayed in the browser, the results are directly downloaded to the users computer using the file name "mission"_search.txt where "mission" is the mission name (e.g., hst_search.txt). Depending on the browser settings, the user may be prompted for a file location before the file is downloaded.
• File: Semicolon-separated values - a simple ASCII text file containing column headings followed by rows of semicolon-separated values. In file upload mode, a blank line is inserted between the search results to separate multiple target queries. Rather than being displayed in the browser, the results are directly downloaded to the users computer using the file name "mission"_search.txt where "mission" is the mission name (e.g., hst_search.txt). Depending on the browser settings, the user may be prompted for a file location before the file is downloaded.

Note: If no entries are found for an entry a "no entries found" message is written in the selected format and the program continues. In all cases, error conditions will cause the database search to abort.