About Chandra Archive Proposer Instruments & Calibration Newsletters Data Analysis HelpDesk Calibration Database NASA Archives & Centers Chandra Science Links

Skip the navigation links
Last modified: December 2006

URL: http://cxc.harvard.edu/ciao3.4/get_metadata.html
Hardcopy (PDF): A4 | Letter
AHELP for CIAO 3.4 get_metadata Context: sherpa

Synopsis

Module functions to retrieve metadata associated with source and background datasets.

Syntax

Integer_Type get_dimension([Integer])
Float_Type get_exptime([Integer])
Float_Type get_bexptime([Integer])
Float_Type get_backscale([Integer])
Float_Type get_bbackscale([Integer])

Error Return Value: NULL

Arguments:

(1) data set number (default 1)

Description

The function get_dimension() retrieves the dimensionality of the appropriate data set (e.g., 1 for PHA data, 2 for images). (If no argument is given, the dimensionality of data set 1 is retrieved.)

The function get_exptime() retrieves the exposure time of the appropriate data set, in seconds. (The function get_bexptime() retrieves the exposure time of the background data set.)

The function get_backscale() retrieves the value of the BACKSCAL keyword associated with the appropriate data set (assuming the file from which that data was read was a PHA file). (The function get_bbackscale() retrieves the value of the BACKSCAL associated with the appropriate background data set.)

See the related Sherpa command SHOW ALL for more information.

Example

sherpa> data example.pha
sherpa> get_exptime()
28678

Bugs

See the Sherpa bug pages online for an up-to-date listing of known bugs.

Hardcopy (PDF): A4 | Letter
Last modified: December 2006



The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory.
60 Garden Street, Cambridge, MA 02138 USA.    Email: cxcweb@head.cfa.harvard.edu
Smithsonian Institution, Copyright © 1998-2004. All rights reserved.