Home > Search Help
This page provides helpful information not only on how to use the
NOAO survey data search form, but also
describes the individual search parameters both in words and with examples
where appropriate. This page also provides documentation regarding the
information on output results page.
You can use the NOAO survey data search form to search the current holdings of data from NOAO surveys by setting the available parameters according to your specific needs. At this time, the available search parameters are: equatorial coordinates (RA and Dec), object name, observation date, photometric depth, survey name, and filter. If you do not recall the coordinates of a particular field, then the Object Name entry can be used in conjunction with a name resolver (SIMBAD or NED) to determine equatorial coordinates which can then be used for your query.
|Particular topics of note will be represented in a highlighted manner.|
If you wish to search the database explicitly for a specified object name, you should fill in the Object Name entry, and you must also set the Resolver to Do Not Resolve. When you are ready to perform the search, just press the Search button located at the top and the bottom of the form. When using the Object Name explicitly to search the archive database, the characters "*" (asterisk) and "?" (question mark) may be used as wild cards. The "*" can be used for matching a series of characters while the "?" can be used for matching a single character. The matches are done in a case-insensitive manner. For example,
Object Name WL* ==> returns objects named in the database beginning with the letters ``WL'' and followed by some number of characters. ?L* ==> returns objects named in the database which have an ``L'' as the second character in the name, preceded by a single character, and followed by some number of characters. ??WL ==> returns objects named in the database which end in the characters ``WL'' and are preceded by two characters. grid 1* ==> returns objects which begin with the characters ``grid'', followed by a single space, the number ``1'', and finally some number of characters.
|In general, unless you are knowledgeable about the details of the particular survey data, it is better to search the archive using coordinates or other parameters. The object names provided with the survey data have not been normalized.|
If you wish to use the Object Name in order to determine coordinates (RA and Dec) for an object via a name resolver, you should fill in the Object Name entry, set the Resolver to SIMBAD or NED to perform the name resolution, and press the Find Coordinates button. When used with a name resolver, wild cards are not allowed for the object name. No quotes (single or double) should surround the text.
Object names to use with the name resolver to obtain coordinates can be in the following format: WLM ngc5548
In order to use the object name resolver, type an object name in
the Object Name text field, select a name resolver
(SIMBAD or NED), and press the
Find Coordinates button. The search form will be redisplayed
right ascension and declination of the specified object in the
RA and Dec fields of the search form.
You do not need to press the Find Coordinates button in order to activate the name resolver. If you have entered an object name in the Object Name entry and you have chosen either SIMBAD or NED, when you press Search, the object name will be resolved to coordinates before a search of the archive database is performed.
However, if you intend to do repeated searches using the same coordinates obtained from SIMBAD or NED, it is recommended that you resolve the coordinates first using the Find Coordinates button, and then do your successive searches.
Decimal hours (RA) and Decimal Degrees (Dec) 0.712311 (RA) and 41.269039 (Dec) 0.712311 (RA) and +41.269039 (Dec) Sexigesimal RA in hours, minutes, seconds Dec in degrees, arcminutes, arcseconds 00 42 44.32 (RA) and +41 16 08.5 (Dec) 00:42:44.32 (RA) and 41:16:08.5 (Dec)For the sexigesimal format, you can only delimit the numerical values with a space or a colon.
|If you enter coordinates in the RA and Dec entries, but you also enter text in the Object Name entry and choose the to resolve the coordinates, the values entered manually in RA and Dec will be ignored.|
|Please see the help for Width to understand how the RA, Dec and Width are used in combination to acquire images from the archive.|
Please see the accompanying graphic for a visual description of how the RA, Dec and Width are used in combination. The object corresponding to the provided RA and Dec values is contained within the light red-shaded box and identified by the black circle at the center of of the box. The length of a side of the red-shaded box (square) is set by the Width value. The red-shaded box is totally encompassed by image 4 (white); the red-shaded box is partially contained within images 2 (green) and 3 (purple). Note only a portion of the red-shaded box need be within an image (2, green) for it to be considered a match to the input criteria; it is not necessary for the input RA and Dec to be within the matching image. Images labelled 2, 3, and 4 will be acquired from the database as matches to the input criteria.
Month DD YYYY or Month-DD-YYYY Jan 01 1999 september-27-2000 Octo 8 1997 MM/DD/YYYY or MM-DD-YYYY <== Note American ordering of values. 01/01/1999 9-27-2000 10/1/1997 DD Month YYYY or DD-Month-YYYY 01 jan 1999 27-sep-2000 1 oct 1997 YYYY Month DD or YYYY-Month-DD 1999 JAN 1 2000-sep-27 1997 oct 01The text representing the month as a string must have at least three characters, and case does not matter. Single digit numerical values can be represented by "01" or "1". The year must be represented by four digits and only years between 1000-2999 are currently acceptable.
The less than ("<") and greater than (">") symbols can be used with the date in order to search for data before a specified date ("<") or after a specified date (">"). For example,
Before a date: < apr 10 1999 < 2000 sep 27 <10/1/1998 After a date: > apr-10-1999 >2000-sept-27 > 10/01/1998
<23.9 > 20.22 21.4 <== This format requires an exact match, so it is limiting and not necessarily useful.
A listing and description of the Survey Programs is available.
|Please be aware the listbox which is used to allow the you to choose multiple entries for Survey (as well as other search parameters) is implemented differently for various browsers. The you should ensure that only the desired selections are highlighted in black.|
Listings and descriptions of the filters at KPNO and filters at CTIO are available.
|Please see Survey help above for more information on the issues related to the listbox widget.|
The output results page provides the user with a tabular listing of results from the database which matches the user's input criteria. In the instance that no matches in the database were found, a message highlighted in red will be displayed at the top of the output results page.
In the instance of successful matches, the number of matches will be indicated at the top of the output results page. This message will be followed by the tabular output information.
If results exceed a specific limit, they are separated into several pages, and links to each page of results are preceeded by "Results Page". The current page is indicated by the page number in bold, and is not a link.
If the database search were invoked using search coordinates, then these columns will also include the the X- and Y-pixel values at the center of the output image, corresponding to the output RA and Dec respectively.
Click on RA(hms) or Dec(dms) to sort the search results. This sorts the images by descending RA or Dec. Click them again to reverse the sort.
The accompanying graphic best illustrates the meaning of these offset values. The light red-shaded box is centered on the input RA and Dec values and the length of the box side is set by the Width parameter. Image 1 is a "match" from the archive which contains a portion of the requested search region. The center of Image 1 in both pixels and sexigesimal coordinates is reported in the output columns RA(hms) and Dec(dms). The offset values are represented in a right-handed coordinate system; positive X is to the right, and positive Y is to the top.
|Survey Name in Search Form||Survey Name From the Database|
|NOAO Deep Wide Field||ndwfs|
|Resolved Stellar Content of Local Group||Local Group|
For specific help on the Image Cutout viewer, click here.
The Selection Cart is a page to centralize selection of various images. Images can be downloaded from this page individually, or through the Bulk Download mechanism.
Click the link in the Download column to download the file. Click the Stage button to prepare the data for bulk download. This feature provides an anonymous FTP connection to the archive, with a directory containing all staged images.
To remove images from the Cart, click the corresponding checkbox in the Remove column, then click Update Cart.
The Bulk Download utility is provided as a convenience to download many images with the least amount of intervention. The results may take a while to appear. Please be patient.
After the data is staged to the anonymous FTP site, information about which images were staged, and instructions on how to access them are presented.
Staged data have a limited lifetime before they are removed from the FTP site. Please be sure to download all data as soon as possible, if not immediately.