  Diffraction-limited images can be obtained with a large optical telescope
using interferometry. One such method for objects of sufficient brightness is
non-redundant masking (NRM), in which observations are made through a pupil
mask that contains an array of small holes. However, NRM only uses a small
fraction of the available light. Here I describe a method for Extended NRM in
which a cylindrical lens allows interferograms from many one-dimensional arrays
to be recorded side-by-side on a two-dimensional detector.
  For fainter objects, the holes in the aperture mask should be replaced by
slits. In this case, the mask can be removed entirely, with the cylindrical
lens effectively creating a continuous series of one-dimensional
interferograms. This modified form of speckle interferometry, which I call MODS
(Multiplexed One-Dimensional Speckle), is intermediate between NRM and
conventional full-aperture speckle. An existing speckle camera can easily be
converted to MODS observations by inserting a cylindrical lens. The feasibility
of both MODS and Extended NRM are demonstrated using observations with MAPPIT
at the Anglo-Australian Telescope.
