Appendix: Available Optical Path Difference (OPD) filesΒΆ

For each of the five instruments (four SIs plus FGS) there are three provided OPD files. These represent wavefronts as follows:

  1. The OTE and ISIM intrinsic WFE
  2. The above, plus a slight defocus to blur the image slightly to approximate image motion.
  3. The above #2, plus additional WFE due to SI internal optics.

The latter is the largest WFE, and is the default file used in simulations unless another is explicitly chosen. For NIRCam only there is a second, duplicate set of these files with slightly improved WFE based on an optimistic case scenario for instrument and telescope alignment.

Note that the trick of adding some (nonphysical) defocus to blur out the PSF is computationally easy and rapid, but does not give a high fidelity representation of the true impact of image jitter. This is particularly true for coronagraphic observations. Future versions of WebbPSF will likely provide higher fidelity jitter models.

Rev V OPDs
File RMS WFE Contents
OPD_RevV_fgs_150.fits 150.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_fgs_163.fits 163.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_fgs_186.fits 186.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus
OPD_RevV_miri_204.fits 204.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_miri_220.fits 220.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_miri_421.fits 421.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus
OPD_RevV_nircam_115.fits 115.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_nircam_123.fits 123.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_nircam_132.fits 132.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_nircam_136.fits 136.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_nircam_150.fits 150.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus
OPD_RevV_nircam_155.fits 155.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus
OPD_RevV_nirspec_125.fits 125.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_nirspec_145.fits 145.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_nirspec_238.fits 238.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus
OPD_RevV_tf_144.fits 144.0 OPD for OTE+ISIM with all reserves and stability; NO image motion
OPD_RevV_tf_162.fits 162.0 Observatory OPD for OTE+ISIM with all reserves and stability, and image motion as defocus
OPD_RevV_tf_180.fits 180.0 Observatory OPD for OTE+ISIM+SI with all reserves and stability, and image motion as defocus

Documentation last updated on June 25, 2012

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