On-The-Fly Calibration
Encyclopedia
An On-The-Fly Calibration (OTFC) system calibrates data when a user's request for the data is processed so that users can obtain data that are calibrated with up-to-date calibration files, parameters, and software.
(ST-ECF) and is implemented at both sites and at Space Telescope Science Institute
(STScI). The OTFC system currently provides data calibration for the Wide Field and Planetary Camera 2
(WFPC2) and Space Telescope Imaging Spectrograph
(STIS). In the future, the Advanced Camera for Surveys
(ACS) and possibly the Near Infrared Camera and Multi-Object Spectrometer
(NICMOS) will be supported.
Currently, for example, HST data are calibrated as they are received at the STScI. Raw and calibrated data are stored in the HST archive (DADS). Frequently, users must recalibrate the data at their home sites to take advantage of better calibration files or software. A large fraction (over 90%) of the calibrated data in the HST archive could be improved by recalibration, although the improvements are not always significant. In the past, instruments that undergo evolution of calibration files or calibration software often required users to carry out their own recalibrations at their home sites. With OTFC, the HST data archives carry out the recalibration.
History of OTFC
The OTFC processing system was developed at the Canadian Astronomy Data Centre (CADC) and the Space Telescope European Coordinating FacilitySpace Telescope European Coordinating Facility
right|The Space Telescope - European Coordinating Facility is an institution which provides a number of support and service functions primarily for European observers of the NASA/ESA Hubble Space Telescope...
(ST-ECF) and is implemented at both sites and at Space Telescope Science Institute
Space Telescope Science Institute
The Space Telescope Science Institute is the science operations center for the Hubble Space Telescope and for the James Webb Space Telescope...
(STScI). The OTFC system currently provides data calibration for the Wide Field and Planetary Camera 2
Wide Field and Planetary Camera 2
The Wide Field and Planetary Camera 2 is a baby grand piano sized camera built by the Jet Propulsion Laboratory and formerly installed on the Hubble Space Telescope. It was installed by servicing mission 1 in 1993, replacing the telescope's original Wide Field and Planetary Camera...
(WFPC2) and Space Telescope Imaging Spectrograph
Space Telescope Imaging Spectrograph
The Space Telescope Imaging Spectrograph is a spectrograph, also with a camera mode, installed on the Hubble Space Telescope. It operated continuously from 1997 until a power supply failure in 2004. After repairs, it began operating again in 2009...
(STIS). In the future, the Advanced Camera for Surveys
Advanced Camera for Surveys
The Advanced Camera for Surveys is a third generation axial instrument aboard the Hubble Space Telescope . The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembled and tested extensively at Ball Aerospace & Technologies Corp...
(ACS) and possibly the Near Infrared Camera and Multi-Object Spectrometer
Near Infrared Camera and Multi-Object Spectrometer
The Near Infrared Camera and Multi-Object Spectrometer is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope , operating from 1997 to 1999, and from 2002 to 2008...
(NICMOS) will be supported.
Goals of the system
The main goals behind the implementation of the OTFC system are to take advantage of better calibration files and the much smaller storage area required if only raw files are kept in the archives. The system can also offer more calibration steps than were available when the data was first released and can implement improved pipeline software.Currently, for example, HST data are calibrated as they are received at the STScI. Raw and calibrated data are stored in the HST archive (DADS). Frequently, users must recalibrate the data at their home sites to take advantage of better calibration files or software. A large fraction (over 90%) of the calibrated data in the HST archive could be improved by recalibration, although the improvements are not always significant. In the past, instruments that undergo evolution of calibration files or calibration software often required users to carry out their own recalibrations at their home sites. With OTFC, the HST data archives carry out the recalibration.