  Most telescope designs have a circular-shape aperture. We demonstrate that
telescopes with an elongated pupil have better contrast, at lower separations,
between a bright central star and a faint companion. We simulate images for an
elongated-pupil telescope and for a circular-pupil telescope of equal aperture
area and integration time, investigating specifically what is the maximal
contrast for finding faint companions around bright stars as a function of
angular separation. We show that this design gives better contrast at lower
separation from a bright star. This is shown for diffraction-limited (for
perfect and imperfect optics) and seeing-limited speckle images, assuming equal
aperture area and observing time. We also show the results are robust to errors
in measurement of the point spread function. To compensate for the wider point
spread function of the short axis, images should be taken at different rotation
angles, either by rotating the telescope around the optical axis or by allowing
a stationary mirror array to scan different parallactic angles with time.
Images taken at different rotation angles are added using the proper image
coaddition algorithms developed by Zackay & Ofek. The final image has the same
contrast in all angles, rather than in specific areas of diffraction nulls. We
obtained speckle observations with a small, ground based elongated-aperture
telescope and show the results are consistent with simulations.
