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| STScI Analysis Newsletter (STAN) for ACS and WFPC2
| 10 December 2003
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CONTENTS:
1. HST Cycle 13 Phase I proposal deadline: 23 Jan 2004
2. ACS and WFPC2 instrument groups merged
3. Instrument and Data Handbooks
4. New versions of the ACS Exposure Time Calculators
5. Update on STSDAS, CALACS, and PyDrizzle/MultiDrizzle
6. Calibration plans and calibration proposals
7. ACS photometric zeropoints and transformations
8. Recent Instrument Science Reports
9. Recent publications
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1. HST Cycle 13 Phase I proposal deadline: 23 Jan 2004.
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2. ACS and WFPC2 instrument groups merged
The ACS and WFPC2 instrument groups at STScI have merged,
which should be largely transparent to ACS and WFPC2 users.
This is the first joint ACS+WFPC2 STAN. The former acs_news
and wfpc_news distribution lists have been merged into the
acs_wfpc2_news list. The instructions for subscribing and
unsubscribing from this new list are given at the end of
this document.
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3. Instrument and Data Handbooks
The ACS and WFPC2 Instrument Handbooks both have undergone
revisions to update for Cycle 13.
The ACS and WFPC2 Data Handbooks are also available from
these sites. Before the end of this year, we plan to
replace the pre-launch ACS Data Handbook with a revised
version. This new version will contain an updated and
expanded discussion of the calibrations applied during
pipeline processing, and demonstrates how to manually
recalibrate data using the CALACS, PyDrizzle, and
MultiDrizzle software. Additional chapters that discuss
photometry, astrometry, polarimetry, and other applications
in detail will be added in subsequent months.
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4. New versions of the ACS Exposure Time Calculators
New versions of the ACS Exposure Time Calculators were made
available on September 10, 2003.
The new ETCs were developed as part of the Astronomer's
Proposal Tool (APT), but are available through a web
interface with the same look-and-feel as the old CGI ETCs.
In addition to the Imaging, Spectroscopic and Ramp Filter
ETCs available under CGI, the APT version includes
Coronographic and Coronographic-with-Ramp ETCs. We
recommend the new APT versions for all users. Details
about new features and improvements in the ETCs are
available via the webpage above.
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5. Update on STSDAS, CALACS, and PyDrizzle/MultiDrizzle
The latest version of STSDAS was released on 20 Oct 2003.
The version of CALACS in this STSDAS release is consistent
with the version currently used in the calibration pipeline.
This version of STSDAS also contains a self-consistent
bundling of PyDrizzle, numarray, etc. These tasks requires
PyRAF version 1.1, which was released simultaneously.
The latest version of MultiDrizzle must still be
downloaded and installed separately.
If you had a previously-installed MultiDrizzle, you will
need to reinstall it after installing STSDAS version 3.1
and PyRAF version 1.1.
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6. Calibration plans and calibration proposals
The current status and accuracy of the ACS and WFPC2
calibrations are described in the respective Instrument
Handbooks.
We welcome all comments on the planned STScI calibration
programs (to help@stsci.edu). Also, GOs are encouraged to
consider the submission of Cycle 13 Calibration Proposals
to take the instrument calibrations beyond the levels
planned at STScI.
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7. ACS photometric zeropoints and transformations
On December 10, 2003 we delivered improved Detectors Quantum
Efficiency (DQE) curves and filter throughput curves to the
ACS pipeline. A detailed description of the new curves will
soon be presented in an Instrument Science Report (ISR)
(De Marchi et al, in preparation).
The new curves reproduce the observed count rate of
spectrophotometric standard stars with an accuracy better
than 1% in all broad band filters, and ~ 1% for narrow band
filters. This is an improvement of 1-2% with respect to the
curves that were previously used by the ACS pipeline.
The new files will automatically be used for the calibration
of any data retrieved from the HST Archive after December 10,
2003. The calibrations only affect the "photometry keyword"
section in the header of the SCI extensions of the
calibrated FITS file. The new zeropoints and the new values
of the keywords are available on the ACS webpage.
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8. Recent Instrument Science Reports
For ACS...
Modelling the fringing of the ACS WFC and HRC chips
Flat Fields for Filter Wheel Offset Positions
Determination of Low-Frequency Flat-Field Structure from
Photometry of Stellar Fields
On-orbit Calibration of ACS CTE Corrections for Photometry
Baseline Tests for the Advanced Camera for Surveys
Astronomer's Proposal Tool Exposure Time Calculator
The in-orbit wavelength calibration of the HRC G800L grism
ACS WFC and HRC field-dependent PSF variations due to
optical and charge diffusion effects
Elevated Temperature measurements of Hot Pixels
ACS Background Light vs. Bright Earth Limb Angle
Stability and Accuracy of HRC and WFC Shutters
NUV Earth Flats
For WFPC2...
WFPC2 Cycle 12 Calibration Plan
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| The Space Telescope Science Institute is operated by the
| Association of Universities for Research in Astronomy,
| Inc., under NASA contract NAS 5-26555.
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