Exposure time calculator

Link to the exposure time calculator (ETC) of FOCAS

July 28, 2022
Now, FOCAS ETC is officially adapted to the IFU mode.
There no longer need to use the following trick for using the ETC.

Note:
This ETC is under development, and only provids a text-based table.
"Source flux" for an extended source shold be given in units of arcsec2.
"Slit width" should be 0.4 arcsec.
"Extraction aperture" is in units of a binded pixel number.
"CCD binning" is [spatial] x [spectral].
"Exposure time" should be the value scaled by the IFU throughput (~0.85) and the slit width (~1.1). When the putative exposuretime is 1200 sec, 1122 sec should be input.