This simulation is an extension of the preceeding experiment (seeh section ) and investigates the influence of the FFTS performance on the quality of the reconstructions. This means that the AO will give a strehl of 0.30 and the FFTS will give a residual OPD error specified by an offset and a jitter (e.g. 0.1 lambda offset and 0.05 lambda jitter). In contrast to the preceeding experiment, all combinations of target and calibrator PSFs are used for the reconstruction, this means, that for example, the target has a PSF with phase error of 0.1 (offset), 0.05 (jitter) and the calibrator has a PSF with a phse error of 0.05, 0.05.

The setup of the simulation is described in table 1. The input data for the test uses a strehl value of 0.30 for the target and the calibrator which has a magnitude of 14. In addition the target and calibrator images are influenced by a gaussian distributed phase error with the same standard deviation, resulting in a fringe contrast loss. This error is modelled as a phase error on the second pupil and for each phase screen (the properties of the atmosphere will result in about 600 phase screens per position angle) a random phase error is introduced. This phase error is specified as a gaussian error with a standard deviation of the OPD between 0.0 (perfect FFTS) and 0.2 lambda (worst case).

The raw data were generated according to the common scheme described in section Overview. In addition the phase screens for the psfs are influenced by a phase error on the second pupil, and the images for the target and psf-star are generated separately which means, that the calibrator image is not influenced by the target (no halo, etc.).

This experiment uses all combinations of target and calibrator PSFs and therefore the number of test cases is extremely high. This means, that only a very small part of the data and results are described in this section.

All simulated input data for the LN DRS pipeline are available as a tar-file (ex4_j_input.tar.gz (???MB) and ex4_k_input.tar.gz (???MB)). The corresponding results are also available as tar files (ex4_j_results.tar.gz (???MB) and ex4_k_results.tar.gz (???MB)).

The generated calibrator raw images are shown in section Calibrator. The raw images and deconvolution results are shown in section Raw Frames and Results for an AGN for the AGN and section  for the star cluster.

The simulated raw LBT interferograms used for the deconvolution are ideal images, they are not influenced by detector effects like different pixel gain or bad pixels. In figure 1 and figure 2 the calibrators for the different phase errors and one position angle are shown.

Figure 1: Central 128x128 pixels of the generated J-Band images of a calibrator with phase error offsets of 0.0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 lambda (from top to bottom) and phase error offsets of 0.0, 0.05, 0.1, and 0.2 lambda (from left to right) .

Figure 2: Central 128x128 pixels of the generated K-Band images of a calibrator with phase error offsets of 0.0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 lambda (from top to bottom) and phase error offsets of 0.0, 0.05, 0.1, and 0.2 lambda (from left to right) .

The basis of the simulation is an image of NGC4151 with an overlayed dust torus (see figure 1). The simulated raw images for a position angle of 108 degree are shown in figure 3 (J-Band) and in figure 4 (K-Band).

Figure 3: Central 128x128 pixels of the generated J-Band images of a AGN with phase error offsets of 0.0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 lambda (from top to bottom) and phase error offsets of 0.0, 0.05, 0.1, and 0.2 lambda (from left to right) .

Figure 4: Central 128x128 pixels of the generated K-Band images of a AGN with phase error offsets of 0.0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 lambda (from top to bottom) and phase error offsets of 0.0, 0.05, 0.1, and 0.2 lambda (from left to right) .

In table 2 (J-Band) and table 3 (K-Band) the errors for the AGN depending on the OPD error are presented.