The HRC-specific filters are mostly UV and blue. The set includes UV and visible polarizers (discussed in Chapter 6), a prism (PR200L, discussed in Chapter 6), three medium-broad UV filters (F330W, F250W, and F220W) and two narrow band filters (F344N and F892N). Use of the UV filters with the WFC is not supported because of the uncertainty of the WFC silver coating transmission below 4000 Å.
All broad, medium and narrow band WFC filters can be used with the HRC whenever a better PSF sampling is required. In general, the throughput of WFC is higher than that of HRC where their sensitivity overlaps. Only some of the WFC ramp filters can be used with the HRC since only the middle ramp segment overlaps with the HRC FOV. In particular, HRC can use the FR459M and FR914M broad ramps, and the FR505N [OIII], FR388N [OII], and FR656N (H) narrow ramps.
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