POA CALFOS is the improved Post Operational Archive version of the Faint Object Spectrograph

Faint Object Spectrograph

The Faint Object Spectrograph was a spectrograph installed on the Hubble Space Telescope. It was replaced by the Space Telescope Imaging Spectrograph in 1997, and is now on display in the National Air and Space Museum in Washington DC. -FOS facts:...

 (FOS) calibration pipeline, an earlier instrument aboard the Hubble Space Telescope

Hubble Space Telescope

The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

 (HST). STScI made an improved version of the FOS calibration pipeline called POA_CALFOS. POA CALFOS replaces CALFOS, which performed the routine calibration of FOS data in the standard IRAF

IRAF

IRAF is a collection of software written at the National Optical Astronomy Observatory geared towards the reduction of astronomical images in pixel array form. This is primarily data taken from imaging array detectors such as CCDs...

/STSDAS FOS calibration pipeline. The current version corrects for image motion problems that have led to significant wavelength scale uncertainties in the FOS data archive. The improvements in the calibration enhance the scientific value of the data in the FOS archive, making it a more homogeneous and reliable resource.

The Faint Object Spectrograph was one of the 4 original axial instruments aboard the HST. FOS was designed to make spectroscopic observations of astrophysical sources from the near ultraviolet to the near infrared. The instrument was removed from HST during the Second Servicing Mission in February 1997 and replaced by the 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). Consequently, no more new FOS observations can be made, and only Archival Research programs may be submitted to make use of FOS data. The Instrument Physical Modeling Group

Instrument Physical Modeling Group

The Instrument Physical Modeling Group of the Space Telescope European Coordinating Facility develops astronomical instruments and physical models of their operation...

 (IPMG) of the Space Telescope European Coordinating Facility

Space 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) currently has the main responsibility for FOS.