In this mode, no pupil masks are used and a high magnification is selected with wheel GR. It corresponds to the ``conventional'' way of observing in speckle interferometry. Most of speckle cameras only offer this possibility (Breckinridge et al. 1979, Strittmater, 1980, Foy, 1988a).
Figure: Full pupil speckle imaging:
restored image of the triple star 2 Cam, at the TBL.
The full pupil is used and the transfer function corresponds to that of the telescope. A drawback of this setup in photon counting mode mode is that low spatial frequencies dominate the transfer function. Furthermore, the diffraction pattern of the spider may pollute the final image and hinder the detection of faint objects in the vicinity of a bright one.
The limited dynamic range of detectors such as the CP40 imposes the use of neutral densities to reduce the photon flux for bright objects. This limits the gain in performances of the restoration methods for bright objects when the photon noise cannot be reduced as is should.