Integration Time Calculator Changes
Changes and bugs (coded red, or black if fixed) within the
Integration Time Calculator are listed below:
- 2 March 2005 - Gemini North ITCs (GMOS North, NIRI including Altair,
Michelle) now default to silver (primary and secondary) mirror coating
- 29 August 2003 - Added Altair + NIRI ITC, implemented as a modification to
the NIRI ITC.
- 25 June 2003 - Updated T-ReCS
"extra low frequency noise" parameter with on-telescope measured
performance, better by a factor of 2.
- 17 April 2003 - major changes to T-ReCS ITC. Detector properties now
correspond to pre-ship AT performance which shows significantly elevated
"extra low frequency noise" (ELFN). Updated filter list and filter
transmission profiles. Added spectroscopy options (gratings, slits).
- 17 April 2003 - added image quality data at 1.2um when using PWFS to
improve interpolation accuracy. See the observing
condition constraints for details.
- 5 March 2003 [fixed in v3.0] - the GMOS South ITC output
incorrectly reports that it is using the GMOS North CCD properties. It is
actually using the correct file.
- 4 March 2003 - updates for semester 03B Call for Proposals. Added GMOS-S
(currently assumes same optical properties as uses same files as GMOS-N but
with blue-optimised detectors). NIRI (v3.1) spectroscopy internal background
degraded to take account of grism scattering, predominantly at L but also
some performance degradation at K and M).
- 4 September 2002 - new releases for all instruments and added Michelle
(all v3.0). Revised image quality percentiles (was [20%, 50%, 80%, any] to
[20%, 70%, 85%, any]). New graphics package.
- 11 March 2002 - new releases for NIRI, GMOS, T-ReCS and AcqCam (all v2.0).
Changes include: revised 80%-ile image quality and 70%-ile, 90%-ile and
"any" cloud cover constraints, GMOS multiple IFU elements, upload
of user-defined input spectra, plus many other changes. See the v2.0 release
notes for details.
- 26 Oct 2001 - corrected GMOS R400 grating dispersion to 0.0673nm/pixel
- 13 Sept 2001 [fixed 19 Sept 2001] - when GMOS spectral binning of 2
or 4 is selected, the wavelength range is not calculated correctly
- 12 Sept 2001 - updated releases of NIRI (v1.2) and GMOS (v1.1) ITCs.
Both include ASCII output spectra; GMOS includes first IFU implementation
and R831 grating.
First release of T-ReCS ITC (v1.0).
- 11 Sept 2001 [fixed 12 Sept 2001] - found in testing T-ReCS ITC
that thermal emission from telescope was not being correctly applied. Will
also have affected NIRI thermal (4 and 5um) calculations.
- 28 Aug 2001 [fixed 1 Sept 2001] - in calculation of flux
in 'peak' pixel for uniform surface brightness emission, flux is not updated
when source brightness is changed although total signal in sq arcsec is
calculated correctly (all ITCs).
- 8 Aug 2001 - GMOS fixed-optics throughput file updated after initial
on-telescope tests; slightly less throughput at blue wavelengths
- 14 Mar 2001 - rarely, if the wavelength of the
emission line SED is given to 3 decimal places the ITC returns "null"; the
workaround is to specify with a precision of only 2 d.p. or change the wavelength slightly
- 2 Mar 2001 - update of NIRI ITC for 2001B Call for Proposals; release of GMOS and AcqCam ITCs.
- 19 Feb 2001 - when the noise from the source flux is
larger than the background, the ITC issues the warning "not background limited",
even when the background noise still exceeds dark and readout noise. Whilst strictly true,
the ITC should note that the observation is source noise limited.
- 16 Nov 2000 [fixed 21 Feb 2001] - in NIRI ITC, 'forward' calculation of total S/N does not given the
same results as the 'reverse' calculation of integration time. Forward calculation
actually gives the correct result.
- 30 Aug 2000 - first public release of NIRI ITC.