FGS Photometry
As a scientific instrument, the FGSs are capable of providing photometric measurements of point sources. The basic
photometric capabilities of the FGS are:
- 40Hz 1-2% long-term relative photometry.
- 40Hz milli-magnitude relative photometry over orbital timescales.
The absolute FGS photometric response of FGS3 has been stable at the 2% level over the past
eight years (L. Reed, BF Goodrich) . FGS1r is expected to be as stable or better. For relative
photometry on time scales of orbits, the FGS has been shown to be stable at the 1 milli-magnitude
level, thus affording an opportunity for 0.1-0.2% time series photometry.
For more specific details on FGS photometry, follow the links to
the documents listed below.
FGS Photometry Documentation:
FAQs:
Frequently Asked Questions.
Q: What photometric information is available from the guiding FGSs regarding the photometry of the Guide Stars?
A: ...
Q: What effect does the color index of the target have on the observed Transfer Function?
A: ...
Performance Summaries:
Status reports reflecting the current
understanding of instrument characteristics,
performance and calibration.
Handbooks:
The FGS Instrument Handbook is the primary
guide regarding the characteristics and use of
the instrument. The HST Data Handbook is the
primary guide for calibration, reduction and analysis
of FGS data.
IHB Chapter 3.6 Relative Photometry
Relative photometry using FGS.
FGS Group 15 Apr 2002 (html)
DHB Chapter 3.3 Analyzing HST Images
This section describes methods for using STSDAS and IRAF to work with two-dimensional image data from HST.
FGS Group 16 Apr 2002 (html)
Instrument Science Reports:
ISRs are technical reports written by members
of the FGS Group about various aspects of the
instrument and data. They usually contain in-depth
information about specific topics.
Addendum: Results From FGS Cycle 5 Calibration Programs #6180 and #6181
Results of the observation of the blue target LAT-COL-1B from Cycle 5 FGS calibration
programs #6180, Red/Blue Transfer Function Calibration for the Clear (F583W), and
PUPIL filters are discussed.
S. Holfeltz 16 Apr 2002 (pdf)
Results From FGS Cycle 5 Calibration Programs #6180 and #6181
Results from Cycle 5 FGS calibration programs #6180 and #6181, Red/Blue Transfer
Function Calibration for the Clear (F583W), PUPIL, and Neutral Density (F5ND) filters
are discussed.
S. Holfeltz 16 Apr 2002 (pdf)
Results From FGS Cycle 5 Calibration Program #6175 3 Points of Light
Results from the Cycle 5 FGS calibration program #6175, 3 Points of Light , are discussed.
S. Holfeltz 16 Apr 2002 (pdf)
Correcting FGS Counts for Deadtime in the PMTs
The procedure to remove the effect of deadtime is described in-depth.
M. Lattanzi 16 Apr 2002 (pdf)
Papers and Proceedings:
Selected FGS related published papers and workshop
proceedings.
The Fine Guidance Sensors Aboard the Hubble Space Telescope, the Scientific Capabilities of these Interferometers
1999 Chicago AAS Poster
Examples:
Examples of how to use various FGS-related tools, calibration and analysis techniques.
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