Main ESO Archive Help Page
|Table of Contents:|
|The following sections provide some help on how to use and what to enter for the various query parameters offered in the Main ESO Archive query form. Access is supplied through the WDB interface. If this is the first time you use this system, we recommend that you read the short WDB help page on how to specify queries and use operators to make full use of this system.|
|This section provides information on the query parameters used to find observations of specific named objects or centered on specified RA and DEC coordinates.|
|Target Name||Specify the name of the astronomical object you want to search for and select the appropriate name resolver from the pull-down menu.
Target identifiers may be resolved into coordinates by Simbad (default),
or matched against the OBJECT keyword value as specified in the data FITS header.
NED is an extragalactic database, hence galactic targets should be resolved by SIMBAD.
If you match the target name against the OBJECT FITS keyword value, it will be wildcarded and the search will be case insensitive: car might return eta car, Cartwheel,... To change this default behaviour, use the following operands:
Solar System bodies cannot be resolved. Thus, if you would like to search for moving targets, enter a target name (e.g. neptune) and do not select any name resolver but instead choose the option 'OBJECT - FITS keyword' from the pull-down menu.
|OBJECT||It is either the target designation (as given by the astronomer) for science exposures or the exposure Type for non-science frames.|
If you search by coordinates or target name, enter here the size
of the search box around the target.
Alternatively, if you search by range in RA and DEC (see below), the Search Box field must be empty.
|RA||Alternatively to the target name, you can specify here the Right Ascension. Recognised format is either
sexagesimal or decimal hours.
For sexagesimal notation, both blanks and colons are accepted as separators between hours, minutes and seconds.
You may also search by range in RA (e.g. 15:00 .. 15:30). If so, be sure to empty the Search Box field.
|DEC||Alternatively to the target name, you can specify here the Declination. Recognised format is either
sexagesimal or decimal degrees.
For sexagesimal notation, both blanks and colons are accepted as separators between degrees, arcminutes and arcseconds.
You may also search by range in DEC (e.g. -51 00 .. -50 00). If so, be sure to empty the Search Box field.
|Input Format||Use the pull-down menu to indicate wether input values for RA are given in hours or degrees.|
|List of Targets||Suppose you have a list of targets and you would like to query the ESO Archive for each target in that list.
Instead of having to re-type the target name or coordinates and run a new search for each target in the list,
you may query the ESO Archive using an input file of targets.
Click on the 'Browse' button to locate and upload the file from your local directories.
The file must contain no more than one target per line. The target can be
A few notes regarding the syntax of the input file:
Do not forget to set the size of the Search Box and the Output Format for coordinates!
|Output Format||Choose here the output format for coordinates: either sexagesimal hours or decimal degrees/hours.
Mark the checkbox to display the coordinates on the query result page. Coordinates are displayed in the field labelled Target Ra, Dec.
|Galactic Search Box||If you search by galactic coordinates, enter here the size of the search box around the target.|
|Galactic Longitude||Search position in galactic longitude. If a precise value is given, then a boxsearch with the size given in the Galactic Search box field is executed.
It is also possible to specify ranges or regions with the .., the < and the > operators. Note that values for the galactic longitudes range from 0 to 360 degrees.
Examples: 100..150 or >200
|Galactic Latitude||Search position in galactic latitude. If a precise value is given, then a boxsearch with the size given in the Galactic Search box field is executed.
It is also possible to specify ranges or regions with the .., the < and the > operators. Note that values for the galactic longitudes range from -90 to 90 degrees.
Examples: -60..-40 or <10
|This section provides information on the query parameters used to find observations carried out during specific nights or in a specific program.|
|Night||Enter here the date of the beginning of the night in DD MM YYYY or
specify a range of nights in the Start and End fields.
An ESO night starts at noon and finishes at noon the following day.
|Start||Enter the date of the first night in DD MM YYYY and select a time from the pull-down menu.|
|End||Enter the date of the last night in DD MM YYYY and select a time from the pull-down menu.|
|Program ID||Read the documentation on the ESO programme identification code.|
|PI and CoIs||Enter here the name of the Principal or Co-Investigator.
You may specify multiple names with the help of the OR operand, e.g. Smith OR Dupont.
|Service/Visitor Mode||Choose Service or Visitor mode from the pull-down menu.|
|Title of the proposal||Enter here words from the title of the proposal.
You may specify multiple words with the help of the OR operand, e.g. galaxy OR massive.
|Data Product Information|
|This section provides information on the query parameters related to a data product and its content. Parameters Category, Type and Mode provide unique high level description of an observation in terms of its purpose and technique. Note that only certain combinations of these keyword values are meaningful.|
|Category|| Choose the observation Category from the list. Multiple choices are allowed.
|Type|| Choose here the type of observation/exposure.
A pull-down menu lists commonly used Type values. It is not intended as a complete list of allowed values. Instead, it is intended as guidelines showing what type of information is included in those parameters.
Alternatively, user defined input may be given in the text field below the pull-down menu.
Indeed, the Type can take more than one value. The values are separated with commas, without any blank spaces. This provides the means to describe a wide range of observations. If more than one value is present, it generally follows the general-to-specific order, i.e. a general term describing the type of technique, followed by qualifiers describing more specific details: e.g. FLAT,LAMP or FLAT,SKY. However, note that some observations are tagged the other way around: e.g. LAMP,FLAT or SKY,FLAT.
Principal values and qualifiers are listed below. More details are available from the ESO data interface web page.
|Mode|| The Mode is the technique used for the observation.
The pull-down menu lists commonly used Mode values.
It is not intended as a complete list of allowed values. Instead, it is intended as guidelines
showing what type of information is included in those parameters.
|Instrument & Mode|| Instruments are splitted into several modes: imaging, spectroscopy, interferometry, polarimetry,
coronography and other.
If you mark one or more instrument checkboxes, constraints both on the instrument ID (ins_id) and the Mode (dp_tech) will be automatically added to your query.
Those constraints are editable in the text field labeled Instrument & Mode.
Additional user defined constraints may be given in that field, provided you follow the SQL-like format.
|Dataset ID||The Dataset ID is the name under which the data product is stored in the ESO Archive.
This unique identifier consists of an instrument prefix followed by a timestamp (e.g. INS.YYYY-MM-DDTHH:MM:SS.sss).
To learn more about the instrument prefix, please visit our FAQ.
The Dataset ID corresponds to the FITS keyword ARCFILE, without the extension.
|Orig Name||The original file name as used on the instrument workstation at the telescope.|
|Release Date||Except for a few special cases, there is a one year proprietary period
for the PI regarding SCIENCE and ACQUISITION frames. Once the proprietary period has expired, data are released.
Frames belonging to all the other Categories, such as CALIB, are immediately public.
|MJD-OBS||(Toggle mode) - MJD-OBS is the modified Julian Date (JD - 2400000.5) of the start of the observation.|
|This section provides information on the query parameters used to find observations carried out with certain constraints as specified in the Observation Block.|
|OB Name||Enter the name of the Observation Block itself, if known.|
|OB ID||Enter the OB Identification here, if known. It should be a unique numeric ID, assigned to the Observation Block by the Observation Handling System.|
|OB TPLNO||(No query, full-screen mode) - It gives the template sequence number within the Observation Block.|
|TPL EXPNO||(No query, full-screen mode) - It gives the current exposure number within the VLT observing template.|
|This section provides information on the query parameters used to find observations according to instrumental setup.|
|Exptime||The exposure time, in seconds. For infrared instruments, the exposure time is computed as DIT * NDIT. For LABOCA, the exposure time may be underestimated due to the continuous data taking setup, which records only exptime of the first subscan.|
|Chip ID||(No query, full-screen mode) - Detector chip identification.|
|Exp ID||(No query, full-screen mode) - Unique exposure ID number.|
This string is in the format <value>,<value>,...
where <value> is the value of one of the FITS keywords INS.FILT*.NAME.
This string is in the format <value>,<value>,...
where <value> is the value of one of the FITS keywords INS.GRIS*.NAME.
This string is in the format <value>,<value>,...
where <value> is the value of one of the FITS keywords INS.GRAT*.NAME.
This string is in the format <value>,<value>,...
where <value> is the value of one of the FITS keywords INS.SLIT*.NAME.
|NX||(No query, full-screen mode) - Number of pixels along X axis.|
|NY||(No query, full-screen mode) - Number of pixels along Y axis.|
|This section provides information on the tools available to find out under which ambient conditions the observations were carried out.|
|DIMM-Seeing||(Toggle mode) - The average FWHM seeing conditions calculated over the exposure time as measured by the DIMM station. The Seeing viewer can be invoked by clicking on the 'DIMM Seeing?' link in the 'Ambient' column of the query result page. Other ambient conditions such as humidity, temperature, pressure, wind speed etc can be obtained from the ESO Ambient Conditions Database Server.|
|Airmass||(Toggle mode) - The airmass at the start of the observation.|
|FITS Header Display||(Toggle mode) - The ESO Archive stores on-line the complete FITS headers of all raw FITS files. The FITS header viewer can be invoked by clicking on the 'Header' link in the 'HDR' column of the query result page.|
|FITS Preview||(Toggle mode) - Previews for the WFI instrument
at the 2.2m telescope in La Silla are now available through the main ESO Archive query form for the year 2005.
More WFI previews from previous years will be posted in the following weeks.
Previews come in JPG and H-compress FITS format ('PRV' column of the query result page).
They are obtained by processing raw WFI frames (already in the public domain) with ESO-MVM in an automated fashion.
An approximate bias subtraction and flat fielding is applied to the
raw frames using master calibrations obtained once a month. A rough
de-fringing for the I- and z-band exposures is applied building fringing
maps from science frames taken over several nights, as in-night widely
dithered science frames are not available for most of these observations.
As a result, the fringing correction is often not satisfactory.
The resulting images are then rebinned by a factor of 10 and compressed using a loss-less algorithm.
To uncompress those files, one can for example apply the standard
imcopy 'file.hfits' file.fits
FITS images contain astrometry (WCS) information with an accuracy of ~1 arcsec.
Preview availability and time coverage:
|Distance||(Toggle mode) - For each source matching your request, the computed distance (in degrees) from the input target will be displayed in an extra column in the query result page. A target is defined either as the name of an astronomical object (e.g. 4C-00.62) or as a set of coordinates (RA=15:00 ; DEC=-51:00). Note that user defined ranges in RA/DEC do not define a target.|
|Position Angle||(Toggle mode) - The position angle of the retrieved observation as seen from the input target (see "Distance" above) from North to East anticlockwise.|
|Number of Frames||(Toggle mode) - Mark the checkbox to get the total number of frames returned by your query, on a per Instrument basis. Statistics will be displayed at the bottom of the query result page.|
|Cumulative Exptime||(Toggle mode) - Mark the checkbox to get
the cumulative Exptime per Filter,
Instrument and Category.
Statistics will be displayed at the bottom of the query result page.
Please note that the Cumulative Exposure Time is overestimated for multi-chip instruments (e.g. FORS2, VIMOS, XSHOOTER).
|Sky Map||(Toggle mode) - Mark the checkbox and the
Aladin Java applet
will provide you with the pointing distribution of all the sources matching your request
and having Ra, Dec information.
Just click on the Aladin logo at the bottom of the query result page.
In addition, the Aladin image server will find the best background image to be loaded (MAMA, DSS2 or DSS1),
provided the size of your search box is less than 6 degrees.
Each matching source displayed in Aladin is colour-coded by instrument and is linked back to the ESO Archive by clicking in the Aladin measurement window:
More about the VOTable description is available at http://www.ivoa.net/Documents/latest/VOT.html.
You may download the VOTable by right-clicking (Save Link Target as...) on the filename votableNUMBER.xml.
If the query results do not contain any Ra, Dec information, no VOTable is produced.
|Mark||To request data please select the datasets in the results table by marking the checkbox in the left-most column, then press the button labeled Request Marked Datasets. Datasets for which the proprietary period is over are highlighted in green and are publicly available. Datasets that are still under the proprietary period are highlighted in red and can only be downloaded by the corresponding PI.|
|- More||If you are in tabular mode and you wish to display the full individual record of a matching source, click on the appropriate magnifying glass in the query result page.|
|Default Mode||(Toggle mode) - By default, if more than one record is retrieved, results will be displayed in tabular mode, one matching record per line. If only one record is retrieved, it is displayed in full-screen mode.|
(Toggle mode) - The VOTable format is a Virtual Observatory standard.
|Tabular Mode||(Toggle mode) - If more than one record is retrieved, or if you mark this checkbox, results will be displayed in HTML tabular format, one matching record per line.|
|Full-Screen Mode||(Toggle mode) - If only one record is retrieved, or if you mark this checkbox, the results of your query will give you the full individual record display, regardless of the selected toggle parameters on the query page.|
|Export File||(Toggle mode) - To export the results of your query to an ascii file,
mark the checkbox and select the field separator from the pull-down menu.
The Export File option requires the tabular mode to be turned on.
If you are in Export File mode, hyperlinks towards external databases (e.g. Program ID) will be turned off in the HTML result table.
Currently available export formats are:
Download query results from: exportNUMBER (format)
To download the export file, right-click (Save Link Target as...) on exportNUMBER.
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Fri Mar 28, 2008
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