FGS Filters

The filter wheel preceding the dielectric beam splitter in each FGS contains five 42mm diameter slots. Four of these slots house filters-F550W, F583W, F605W and F5ND-while the fifth slot houses the PUPIL stop. This stop helps restore the S-Curve morphology throughout the FOV of each FGS by blocking out the outer 1/3 perimeter of the spherically aberrated primary mirror. The filter selection for each FGS, their central wavelengths, and widths are listed in the table below. The transmission curves (filters and PUPIL) and PMT efficiencies are given in the figures below.

Table 1. Available Filters

Filter	Central Wavelength Å	Spectral Range Å	FWHM Å	FGS
F583W	5830	4600-7000	2340	1,1R,2,3
F605W	6050	4800-7000	1900	1,1R,2
PUPIL	5830	4600-7000	2340	1,1R,2,3
F550W	5500	5100-5875	750	1,1R,2,3
F650W	6500	6200-6900	750	3
F5ND	5830	4600-7000	2340	1,1R,2,3