Status:

Caveats:
The off-axis effective area is incorported into the CALDB as vignetting correction factors to be applied to the on-axis effective area.

These values are based upon simulations of the HRMA's off-axis performance, and do not at present take into account the physical sizes of the detectors. This will affect their applicability for sources near the detector edges.

We are in the process of producing corrected values, based upon detector geometry and validations against ground and on-orbit measurements.

Data files:

• The CALDB contains the official off-axis vignetting tables

Analysis:

• A Measurement of the HRMA Vignetting with Abell 1795 (Eli Beckerman, 10/25/04)
• Measurement of Telescope Vignetting with SNR G21.5-0.9 (Eli Beckerman, 10/27/03)
• HRC-I and HRMA Calibration Using RXJ1856.5-3754 (Brad Wargelin, 11/6/02)
• Measurement of Telescope Vignetting from G21.5-0.9 Off-axis Observations( Beth Biller, 7/11/02)

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