ACS Exposure Time Calculators (ETCs)
ATTENTION!!!
For current ACS ETC runs, please start by using the following link and ignore
the older information farther below!
Link for current ACS ETC
Ignore information below this point if you want the current ETC. If you want
the current ETC, use the link above!
The February 2005 on-orbit tests of ACS instrument performance
in two-gyro mode indicate that the exposure time differences
between two-gyro mode and three-gyro mode operations are negligible.
The existing ACS ETCs are appropriate for either mode, and there is no
longer any need to choose between the two modes within the ETCs. If this
situation changes, the ACS Team will provide updated information
on this web page.
On Monday, April 26, 2004 newer, revised ETCs
were released.
The following enhancements are implemented:
1) available but unsupported modes for calibration
purposes (e.g. clear-clear) are now allowed to
compute
2) newer dark rates values for the WFC and the HRC
are in place (WFC: 11.1 e-/pix/hr or 3.08 e-3 e-/px/sec
and HRC: 13.4 e-/px/hr or 3.72 e-3 e-/px/sec).
3) a fix was applied to the SBC modes to more accurately
calculate the global limit for extended sources
greater than the size of the detector.
On September 10, 2003 a revised version of the ETCs for ACS is
delivered. This release is primarily focused on usability
improvements
including better handling of invalid input data and clearer
error and warning messages.
Other improvements:
1. This version uses a newer release of the Tomcat web server
(4.1.27) and a newer release of the Java Virtual Machine (1.4.2).
2. More complete extraction region tables have been included that
support circular regions up to 4 arc seconds in radius
containing 100% of the flux.
3. The output pages have been reformatted to improve readability.
The new Exposure Time Calculators linked above were recently developed
as part of the Astronomer's Proposal Tool (APT). The links provide
access through an interface with the same look-and-feel as the old
(CGI) ETCs. We recommend the new APT versions for all users. They have
several new features and improvements, as described here. For problems
or questions please email help@stsci.edu.
The Old CGI ETCs are still available through the links below. WARNING:
They are not recommended for use and will soon be retired.
|