Large Binocular Cameras

EF Analysis

2009 09 04 Tests of EF analysis of LBCR/B images

LBC/EF Comparison for 2009 09 04 Comparison of EF and LBCFPIA results

FPIA Z4 Calibration Calibration of Z4

FPIA Z11 Calibration Calibration of Z11 based on data from 20091023

UPdated FPIA Z11 Calibration Updated Z11 results from data from 20091023

FPIA Z22 Calibration Calibration of Z22 based on data from 20091023

FPIA Calibration with Big 100 pixel pupils Calibration of Z11, Z22, Z5, Z7, Z4 with ~100 pixel pupils. Data from 20091023

The results of FPIA in the above links were computed with the same configuration file that is used for dofpia. The values of SphOffset and SphRedCorrection were set so that convergence would be reached for a pupil to which some spherical aberration was added to make the inner hole larger and easier for FPIA to measure. This spherical aberration is removed after the last iteration. So in dofpia, convergence is to a pupil with an inner hole to outer diameter ratio = 0.2 (Blue); this spherical, Z11, and the corresponding defocus, Z4 = -1.9* Z11 are estimated and added to whatever lbcfpia computes on the last pupil image in the iterative dofpia routine.

However, to obtain accurate results for Z4 and Z11 for these extra/intra focal pairs which were taken outside of dofpia, the equation for the Z11 computation needed to be edited, so that the convergence would be to a pupil with no Z11 added. Ideally convergence should be to the expected dimensions for a star 0.8mm out of focus. However, the measured values for these out of focus stars are not in exact agreement with the model, and instead the values we assumed in editing this equation were determined by measuring two sets of collimated pupils: blue pupils lbcb.20091023.082418 and 082751 and red pupils lbcb.20091023.082413 and 082744. Although the red pupils were smaller on both images, we took the nominal value 62.4, which is determined by the value of alpha = 78, for both blue and red. We assumed different ratios for the inner hole to outer diameter for blue and red.

The original values for the ratios (inner hole/outer diameter) and outer diameters, and for the parameters, SphOffset, SphRedCorrection are listed in the table below as well as the edited values for running the code outside of dofpia.

channel	original					modified
	Inner/Outer	Outer D	SphOffset	SphRedCorrection	alpha	Inner/Outer	Outer D	SphOffset	SphRedCorrection	alpha
Blue	0.200	62.5	88		78	0.16	62.5	-396		78
Red	0.219	58	88	225	78	0.20	58	-396	484	78

Results for the two sets of collimated pupils with the original and with the modified parameters:

original
channel	filename	Z4	Z5	Z6	Z7	Z8	Z11	Z22
Blue	lbcb.20091023.082418.fits[2]	-1351.11	-3.21135	-163.942	-53.0878	-10.4714	667.978	43.4787
Blue	lbcb.20091023.082751.fits[2]	-835.717	141.237	-277.569	-97.3532	-49.2375	544.321	73.7577
Red	lbcr.20091023.082413.fits[2]	-380.742	34.3555	-266.133	3.35116	-119.541	201.352	12.0603
Red	lbcr.20091023.082744.fits[2]	-521.220	-11.5798	-249.260	141.456	-163.700	314.306	-0.349864
modified
channel	filename	Z4	Z5	Z6	Z7	Z8	Z11	Z22
Blue	lbcb.20091023.082418.fits[2]	-247.595	-3.21135	-163.942	-53.0878	-10.4714	87.1777	43.4787
Blue	lbcb.20091023.082751.fits[2]	267.803	141.237	-277.569	-97.3532	-49.2375	-36.4792	73.7577
Red	lbcr.20091023.082413.fits[2]	230.679	34.3555	-266.133	3.35116	-119.541	-120.448	12.0603
Red	lbcr.20091023.082744.fits[2]	90.1999	-11.5798	-249.260	141.456	-163.700	-7.49356	-0.349864

FPIA Z11 modified for use outside of dofpia Z11 results modified for use outside of dofpia, i.e. for convergence to a pupil with no spherical aberration. From data from 20091023

FPIA Z22 modified for use outside of dofpia Z22 results modified for use outside of dofpia, i.e. for convergence to a pupil with no spherical aberration. From data from 20091023

-- DougMiller - 08 Oct 2009