Topic Index:
The NOAO VO Portal can access and analyze any data in public digital archives that follow VO standards, including the image archives of the NSA, CHANDRA, GALEX, HST, INT, SDSS, and XMM.
A tutorial is provided for each Portal page, a link to which is provided at the top of NOAO-Sky, Time, Access, Access/Analyze, SIA and Query. Additionally, example projects may be found at http://nvo.noao.edu/noaonvo/help.shtml.
You will need to use Mozilla 1.7+, Firefox 1.4+ or Netscape 7.2+. Neither Safari nor IE work completely, and some functionality may be lost, with no warning to the user.
The translation from browser pixel to RA/Dec is dependent on the relative size of the pixel (i.e., the zoom level). Try zooming in one level and then double-click again. Make sure you scroll down (using your browser scroll control) to see the list. If nothing appears in the list but you see data under the mouse. Please contact us at vohelp@noao.edu and provide us with a few details.
This can happen on some systems (notably MacOSX), particularly after changing zoom levels, or after "flying" to a location and zoom level. Try resizing the browser window, or panning with the cursor.
There is a control panel to display wireframe and a control panel to search archives. If a wireframe is displayed and seen on the sky, a user can double-click the mouse on that wire image for access to that data. When searching the viewing window (via the "New Search" link), only data which are check-boxed (above the New Search link) are searched, regardless of whether their wireframes appear. A separate reason why you may see data in the list after clicking the "Search" button but not on the sky is because the Database query used by the "Search" method finds data between the minimum and maximum RA/Dec seen in the viewing window. Since the Hammer-Aitoff projection is used, the curved surface causes a wider search range than is visible near the poles.
The format for coordinates may be sexagesimal (with RA specified in hours) decimal degrees, or a combination of the two. For example: 12:22:31.98, 29:53:45.55 185.63325, 29.895986111 185.63325, 29:53:45.55 Note that sexagesimal format must be specified completely: degrees/hours, minutes, and seconds must all be present and delimited by a colon. One coordinate pair may be specified per input line. And don't forget to include a comma to separate RA from Dec.
A Hammer-Aitoff projection.
The NOAO-Time Calendar view defaults to 1 January 2001. Click and pan on any of day, month, or year panes to move forward or back in time, until data appear in the upper pane.
The staging messages tell you the status of each file that Portal is attempting retrieve from an Archive. They are as follows: NOT_ENQUEUED: Initial state, where requested data product is waiting to enter the Portal staging queue NOT_STAGED: Data product is in staging queue, but has not begun transfer to the ftp area STAGING: Requested data product is being transferred to the ftp area STAGED: Data product is ready for user download from the ftp area TIMEOUT: Connection from Portal to Archive has been lost ERROR: Data product was not successfully transferred to the ftp area; user must re-request data The Portal attempts multiple times to stage each data product after an error occurs before aborting.
The request from the Portal to the Archive to stage data can time out under conditions of heavy user load. The request will be re-queued a few times before aborting the attempt to stage given dataset. If this occurs, the NSA may be unavailable. Wait for at least an hour before attempting to re-stage the affected data.
The simple query provides a familiar, forms-based style for user input to define the query. It however does not allow for the full range of relational expression that is enabled by the advanced query. The simple query fields are limited to those for which the underlying metadata have been validated and are believed to be correct.