52X0.2E1, 52X0.2E2, and 52X0.2D1 Pseudo-apertures

Description

These pseudo-apertures are the same physical aperture as the 52X0.2 aperture, but are used to place the target at different locations on the detectors to reduce CTE loss or FUV-MAMA background. It is yet to be determined if the throughput for a target at these positions is significantly different from that obtained at the standard position. The usage of these slits is supported only for certain modes, as listed in the table below.

Special Considerations

Same special considerations as for the 52X0.2 aperture apply to these pseudo-apertures. See reference information on previous page.

Aperture	Detector	Allowed Gratings	Usage
52X0.2E1	CCD	All CCD gratings	Places the target at row ~900 to minimize CTE effects
52X0.2E2	CCD	G750L and G750M	Places the target at row ~900 to minimize CTE effects; positions are offset from the physical aperture, to give better alignment with fringe flats done using 52X0.1 aperture
52X0.2D1	FUV-MAMA	G140L and G140M	Places the target 2 arcseconds above the bottom edge of FUV-MAMA; intended for observations of very faint targets where dark current contribution should be minimized