Integration Time Calculator v2.0 Release Notes

Changes included in the v2.0 releases (issued 8 March 2002) are listed below.

Changes common to all ITCs:

User-defined source spectra can be used instead of the existing template and model SEDs. Note the following restrictions on file format:

Two space-separated columns: (1) wavelength in nm (2) flux density in arbitrary units. Files can have any number of comment lines, each starting with the # character, and any number of blank lines.
Wavelength interval need not be uniform.
Flux density must be in wavelength units (e.g. per nm or per um, but not per Hz).
Wavelength range must extend to include the requested normalisation filter (or wavelength). For example, a user-defined spectrum for T-ReCS must extend to below 2000nm if the source brightness is defined in the K-band.
File size must be less than 1MB.

80%-ile image quality degraded to provide better sampling of the range of expected conditions. The corresponding image size is defined in the observing condition constraints.
Cloud cover constraints for 70%-ile, 90%-ile and "any" bins changed to provide better sampling of the range of expected conditions. The corresponding transmission is defined in the observing condition constraints.
Input parameters are now reported in full at the bottom of the results page.
Performance improvements of 35-40% for imaging and spectroscopy calculations were achieved.

NIRI changes:

Transmission curves updated for several narrow-band filters {specify}
Slid width and corresponding spectral resolution updated for 6-pixel center slit to match new physical slit. User interface now defines slit width in pixels (was in arcsec) to be consistent with PIT and OT and to avoid future updates when small changes are made.

GMOS changes:

Size of IFU element corrected (hexagonal input aperture approximated by 0.19 arcsec square; was 0.21 arcsec).
Added radial range of IFU elements to extend previous single-element case. IFU elements have offsets of 0.20 arcsec. As before, the S/N is calculated for individual elements.
All gratings (including those not currently installed) made available for ITC.

AcqCam changes:

T-ReCS changes:

Integration time now specified explicitly, replacing specification using individual frame time and number of frames. As a placeholder, frame times of 20ms and 100ms are assumed for imaging and spectroscopy calculations.
Added non-stellar SEDs for planetary nebula, starburst galaxy, pre-main sequence star and the Galactic center. SEDs derived from ISO spectra.