AO
Announcement of opportunity number (proposal round) of which the observation was a part
Approved Exposure Time
Approved exposure time for the observation in ks

Data Entry Information: This field may consist of a comma delimited list of approved exposure time ranges. See the section on Valid Range Format for more information.
Average Count Rate
The average count rate in counts per second(hz). This is the L2 event count divided by the L2 exposure time.

For alternating exposure observations the counts, exposure time, and count rate reflect the values for the secondary exposures, since they receive most of the exposure time. Count rates for the primary exposures are typically 1.5 to 2.0 times the secondary count rates because of the reduced pile-up.

Data Entry Information: This field may consist of a comma delimited list of count rate ranges. See the section on Valid Range Format for more information.
Coordinate Display Format
The user may specify whether the output positions in the search results appear in sexagesimal (HMS/DMS) units or in decimal degrees. For equatorial coordinates, if sexagesimal is chosen, the RA will be displayed in hours/minutes/seconds. For ecliptic or galactic coordinates, if sexagesimal format is chosen, the longitude (Long/l) will be displayed in degrees/minutes/seconds.
Coordinate System
Coordinate System of the position. Choices for a cone search are Equatorial (FK4 and FK5), Ecliptic, and Galactic. Choices for a range search are Equatorial (FK5) and Galactic.
Creation Date
The date on which the file was created
Custom Selection
Sends the user to the Custom Package Page where the user can create a custom package of products to add to the retrieval list.
Data Mode
Datamode contains information for ACIS observations on two components of the instrument set-up:

read mode
event format

It follows the same encoding as the keyword DATAMODE in the FITS files:
Read Mode Event Format Data Mode
TE F FAINT
TE F+B FAINT_BIAS
TE VF VFAINT
TE G GRADED
CC F or F3 CC33_FAINT
CC F1 CC_FAINT
CC G or G3 CC33_GRADED
CC G1 CC_GRADED

Currently for HRC observations Data Mode is null.
Dec/Lat/b
Declination/Latitude of the position

Data Entry Information: See the section Valid Coordinate Format for information on valid input coordinate formats. For a cone search, the radius must be specified. For a range search, the user can specify either the min, the max, or both. If only one is specified the range search will be open ended.
Description
A short description of the data product.
Detector
The detector/instrument used for the data product.
Display
Customizations on the display of the search results
Equinox
Equinox corresponding to the coordinate system

Data Entry Information: If this field is empty, the default values of 2000 (for Equatorial J2000) or 1950 (for Equatorial B1950 or Bxxxx and for Ecliptic B1950 or Bxxxx) will be used.
Event Count
This is the L2 event count.

For alternating exposure observations the counts, exposure time, and count rate reflect the values for the secondary exposures, since they receive most of the exposure time.
Exposure Mode
The exposure modes are : Data Entry Information: See Multiple Selection Lists for more information on using lists
Exposure Time
Actual exposure time(s) for the observation in ks.

For alternating exposure observations the counts, exposure time, and count rate reflect the values for the secondary exposures, since they receive most of the exposure time.

Data Entry Information: This field may consist of a comma delimited list of exposure time ranges. See the section on Valid Range Format for more information.
File Name
Name of a file in the archive for the observations and products selected. The file is usually stored in a gzip-compressed format but the filename does not reflect this.
File Size
Size in bytes of the file. This is the original length, not the length of the compressed version of the file.
File Type
The short name of a type of file, as shown as "CONTENT" in the guide to Chandra data products.
File Upload
The user may select a local file of coordinates or target names to use as a basis for a search. To unselect a file you will need to hit New Search or press Reset. There is a maximum of 5000 coordinates or target names allowed for upload.

List of Coordinates:
The upload file must be a text file with two columns either separated by a comma or by a tab. The first column must be the longitude, the second the latitude. If there is a header (such as "RA,DEC") it will be ignored. See the section Valid Coordinate Format for information on valid input coordinate formats. A cone search will be performed on each of the coordinates in the file. Use the Coordinate System field to specify the coordinate system used in the file. Use the Radius field to specify the search radius for the cone search.

Any blank lines or lines beginning with a hash symbol (#) will be ignored.

List of Target Names:
The upload file must be a text file. Each line in this file will be used in a search to match with a Target Name. The matching is case insensitive and spaces are ignored. For instance, a row containing "cra" will match the targets "CRAB NEBULA" and "RCRADARKCLOUD". Note that the names will not be resolved into coordinates.

Any blank lines or lines beginning with a hash symbol (#) will be ignored.

Grating
The three choices for the gratings are: Data Entry Information: See Multiple Selection Lists for more information on using lists
Grid
Grid name assigned if this observation is part of a user-defined grid

Data Entry Information:
Instrument
The two Chandra instruments are: Each has a spectral (-S) and an imaging (-I) component.

Data Entry Information: See Multiple Selection Lists for more information on using lists
Joint Observatories
Other observatories that were approved as part of this observation (if any). The Joint Observatory options are: Data Entry Information: See Multiple Selection Lists for more information on using lists
Level
The processing levels used in automated processing to produce the product: L0, L0.5, L1, L1.5, or L2.
Name Resolver
Name of the service or services that will be used to resolve the target name when the Resolve Name button is pressed. The services will be chosen in the specified order. For example, "NED/SIMBAD" will first search for the target name in NED and then, if the name was not found, in SIMBAD.
Observation ID
Observation identification number

Data Entry Information: This field may consist of a comma delimited list of obsid ranges. See the section on Valid Range Format for more information.
Observer Name
Last name of the Observer. The Observer is either the Principal Investigator or a Co-Investigator designated by the Principal Investigator to be responsible for the observation.

Data Entry Information: The matching is case insensitive. Any Observer Name that contains the entered value will be returned.
For example, entering smith could match:
Observing Cycle
The observing cycle for the observation. This is the cycle during which the observation should be observed.

Data Entry Information: See Multiple Selection Lists for more information on using lists
Package
Determines if this data product is primary, secondary, or supporting.
Password
Personal archive accounts and proposal accounts both have passwords that can be changed from a link on the archive login page. If the password has been forgotten, a request for a password reminder email to be sent to the account holder can be made from a link on the archive login page.
PI Name
Last name of the Principal Investigator

Data Entry Information: The matching is case insensitive. Any PI Name that contains the entered value will be returned.
For example, entering smith could match:
Primary Package
The package of primary data products. This package contains all products necessary for analysis if the CXC's Automated Processing is deemed satisfactory. If any corrections are to be made, the Secondary Products are required as well.
Product(s)
The product's File Type, or "all" to show that all of the products in the primary or secondary package are in the retrieval list.
Proposal Cycle
The Call for Proposal (CfP) cycle of which the observation was a part.

Data Entry Information: See Multiple Selection Lists for more information on using lists
Proposal Number
8-digit number identifying the proposal for an observation

Data Entry Information: This field may consist of a comma delimited list of proposal number ranges. See the section on Valid Range Format for more information.
Proposal Title
The title of the proposal

Data Entry Information: The matching is case insensitive. Any Proposal Title that contains the entered value will be returned.
For example, entering observ could match:
Public Release Date
Public release date(s) of the observation

Data Entry Information: See the section Valid Date Format for legal date formats.
RA/Long/l
Right Ascension/Longitude of the position

Data Entry Information: See the section Valid Coordinate Format for information on valid input coordinate formats. For a cone search, the radius must be specified. For a range search, the user can specify either the min, the max, or both. If only one is specified the range search will be open ended. If the min value is greater than the max value the range search will wrap around.
Radius
Radius for the cone search in arcmin
Readout Detector
The detector for which there is Chandra data. For ACIS observations, a listing of the chips will be provided for each observation in the search results.
Row Limit
Choose the maximum number of rows to display. The recommended maximum number is 50. This is because early versions of some browsers take a long time to generate the results when much more than 50 results are returned. If "No Limit" is selected and the search criteria do not limit the results sufficiently, the user may experience an unacceptable delay.
Save As
The default is to proceed to the Search Results HTML page

The choices for saving the output results to file are:
Science Category
Science category of the proposal for the observation

Data Entry Information: See Multiple Selection Lists for more information on using lists
Secondary Package
The package of secondary data products. If the user needs to make any corrections to the CXC's Automated Processing, this package is required in addition to the Primary products.
Sequence Number
Six-digit sequence number. For Engineering Requests this value is empty.

Data Entry Information: This field may consist of a comma delimited list of sequence number ranges. See the section on Valid Range Format for more information.
Sort Order
The order in which the search results are displayed. The user may choose to sort by any element in the selection list. The user also specifies whether the results should be sorted in ascending or descending order.
Start Date
Start date(s) and time(s) of the first (or only) observation interval of the observation

Data Entry Information: See the section Valid Date Format for legal date formats.
Status
The observation status can be any of the following values: Data Entry Information: See Multiple Selection Lists for more information on using lists
Supporting Product

The supporting products are the products in the Guide to Chandra Archive Data Products which are neither primary nor secondary. This includes telemetry products, mission products, EPHIN products, PCAD products, ACIS or HRC products, TEL products, SIM products, Ephemeris products, and Engineering products.

Note that there are certain low-level (telemetry, L0) supporting products that are not available through WebChaser, because they may contain a mix of public and proprietary data. These products can be made available through a special request, but users are warned that their usefulness is extremely limited since they are not supported in CIAO tools.

The following supporting products are not available in WebChaser: evt0, img0, exr, hrcss, epheio, ephhist, ephhk, ephpha, ephtlm, ephrates, ephhk_cln, and all raw files.
Target Name
Name of the observed object

Data Entry Information:
The matching is case insensitive and spaces are ignored. Any Target Name that contains the entered value will be returned.
For example, entering crab will match:
TOO: Alternate Target Group and Approved Triggers
Target of Opportunities may have several alternate targets for a defined alternate target group in a proposal. For this group of targets there is an approved number of triggers. Once the approved number of triggers has been met, the addtional observations will be canceled.
Totals
The totals of the selected rows on the Search Results page for a column. Totals are provided for the approved exposure time, exposure time and event count columns.
Type
The observation type can be any of 5 values: Data Entry Information: See Multiple Selection Lists for more information on using lists
Username
If you have a personal archive account you may login using its username. Alternatively accounts are set up for the duration of an observation's proprietary period where the username is the observation's proposal number.
Valid Coordinate Format
Target coordinates may be specified in decimal degrees or in sexagesimal format (hours/minutes/seconds or degrees/minutes/seconds) using either colons or spaces as separators. If the user enters decimal values for RA and Dec, they are assumed to be in decimal degrees. To specify decimal hours, add "h" or "H" after the number.

Examples:
RA Dec System Translation
20h 51m 06s +30d 41' 00" J2000 20 51 06.00 +30 41 00.00
20 51 06 +30 41 J2000 20 51 06.00 +30 41 00.00
20:51:06.0 +30:41:00.0 J2000 20 51 06.00 +30 41 00.00
23.7654 +0.6857 J2000 01 35 03.70 +00 41 08.52
23.7654h +0.6857 J2000 23 45 55.44 +00 41 08.52
18 12.5 -12 8.5 J2000 18 12 30.00 -12 08 30.00
355 51 06 +30 41 Galactic 355 51 06.00 +30 41 00.00

For equatorial coordinates, if the RA is in sexagesimal format it is assumed to be in hours/minutes/seconds. For ecliptic or galactic coordinates, if the RA is in sexagesimal format it is assumed to be in degrees/minutes/seconds.
Valid Date Format
date = YYYY-MM-DD [hh:mm]

dateRange = date[/date] or /date or date/

valid date format = dateRange[,dateRange][,dateRange][...]
Examples:
Example Date(s) Description
2002-01-27 select all observations with a date occurring during the 24 hours of January 27, 2002
2002-01-26, 2002-01-29 select all observations with a date occurring on either January 26, 2002 or January 29, 2002
2001-11-28/2001-11-30 select all observations with a date occurring between November 28, 2001 and November 30, 2001 (inclusive)
2001-06-15 04:00/2001-06-18 23:25 select all observations with a date occurring between June 15, 2001 4:00AM and June 18, 2001 11:25PM
2001-05-20,2001-05-25 14:00/2001-05-28 17:00 select all observations with a date occurring on May 20, 2001 or between May 25, 2001 2:00PM and May 28, 2001 5:00PM (note that the comma delimited list may contain ranges)
/2000-07-01 select all observations with a date occurring on or before July 1, 2000
/2000-07-01 19:00 select all observations with a date occurring at or before 7:00PM July 1, 2000
2000-07-01/ select all observations with a date occurring on or after July 1, 2000
2000-07-01 19:00/ select all observations with a date occurring at or after 7:00PM July 1, 2000

Valid Range Format
range = value[-value] or value- or -value

valid range format = range[,range][,range][...]
Examples:
Example Range(s) Description
1000 the range is simply the single value 1000
1000, 2000 the range is the value 1000 and also the value 2000
3000-5000 the range is all values between 3000 and 5000 (inclusive)
1000, 2000, 3000-5000, 7000-8000, 9000 the range is 1000, 2000, 3000 to 5000 (inclusive), 7000 to 8000 (inclusive), and 9000
350- the range is all values greater than or equal to 350
-1000, 2000-3000 the range is all values less than or equal to 1000, along with all values between 2000 and 3000 (inclusive)