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STScI Exposure Time Calculators Oversight

PYSYNPHOT Calls

Table 5 lists the required pysynphot Calls for various types of ETC requests.

Table 5 Required SYNPHOT Calls

 

Imaging count rate

Spectroscopic count rate

Thermal count rate

Effective Wavelength

NICMOS and WFC3/IR Imaging Source and sky   Yes Yes
NICMOS and WFC3/IR (Slitless) Spectroscopy Sky Source Yes Yes
COS Imaging Source and sky No No Yes
COS Spectroscopy No Source[1] and Sky[2] No No

Other Imaging

Source and sky No No Yes

Other Slitless Spectroscopy

Sky Source No No

Slitted Spectroscopy

No Source[3] and sky[4] No No

Imaging with coronagraphy

Field source, central source, sky No No Yes

[1] Extended sources: The source is assumed to fill the aperture. A pixel-wise convolution is applied over the width of the aperture (2.5 arcsec). For purposes of the convolution only, a simplifying assumption is employed — the aperture is assumed to be rectangular. The values for various total counts are corrected for the actual shape

[2] Sky background: A pixel-wise convolution is applied over the width of the aperture (2.5 arcsec). For purposes of the convolution only, a simplifying assumption is employed — the aperture is assumed to be rectangular. The values for various total counts are corrected for the actual shape

[3] If the source is extended, a pixel-wise convolution is applied over the larger of the target width and the slit width (in pixels).

[4] A pixel wise convolution is applied over the slit width in pixels.