SYNPHOT and PYSYNPHOT Calls


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SYNPHOT and PYSYNPHOT Calls

In Table 5 Required SYNPHOT Calls, the required synphot calls are listed for various types of ETC requests.

	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[1]	Source and sky	No	No	Yes
COS Spectroscopy[1]	No	Source[2] and Sky[3]	No	No
Other Imaging	Source and sky	No	No	Yes
Other Slitless Spectroscopy	Sky	Source	No	No
Slitted Spectroscopy	No	Source[4] and sky[5]	No	No
Imaging with coronagraphy	Field source, central source, sky	No	No	Yes

Table 5 Required SYNPHOT Calls

[1]Because of accuracy issues with the SYNPHOT single precision floating point implementation for all calculations, all COS calculations are made using PYSYNPHOT.

[2]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

[3]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

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

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