Introduction to stellar coronagraphy
نویسنده
چکیده
This paper gives a simple and original presentation of various coronagraphs inherited from the Lyot coronagraph. We first present the Lyot and Roddier phase mask coronagraphs and study their properties as a function of the focal mask size. We show that the Roddier phase mask can be used to produce an apodization for the star. Optimal coronagraphy can be obtained from two main approaches, using prolate spheroidal pupil apodization and a finite-size focal mask, or using a clear aperture and an infinite mask of variable transmission.
منابع مشابه
Total coronagraphic extinction of rectangular apertures using linear prolate apodizations
This paper presents a theoretical study of stellar coronagraphy with apodized entrance apertures. The study is restricted to a perfect telescope operating in space, and a monochromatic on-axis unresolved star. It is shown that linear prolate functions are the optimal apodizers for rectangular apertures in stellar coronagraphy. With the phase mask technique (Roddier & Roddier 1997), prolate func...
متن کاملNICMOS Coronagraphy: Recalibration and the NICMOS Legacy Archive PSF Library
NICMOS coronagraphy, with well-matched template Point Spread Function (PSF) subtraction, probes the closest environments of occulted targets with the highest imaging sensitivity in intrinsically high contrast fields at the smallest radial distances afforded, uniquely, by HST. NICMOS PSF-subtracted coronagraphy has been invoked in a wide variety of HST programs with science themes as divergent a...
متن کاملSubwavelength surface-relief gratings for stellar coronagraphy.
We present a new design of a phase mask coronagraph implemented with subwavelength diffractive optical elements consisting of optimized surface-relief gratings. Phase mask coronagraphy is a recent technique that seeks to accommodate both high dynamic and high angular resolution imaging of faint sources around bright astrophysical objects such as exoplanets orbiting their host stars. The origina...
متن کاملCoronagraphic Imaging with HST and STIS
Revealing faint circumstellar nebulosity and faint stellar or substellar companions to bright stars typically requires use of techniques for rejecting the direct, scattered, and diffracted light of the star. One such technique is Lyot coronagraphy. We summarize the performance of the white-light coronagraphic capability of the Space Telescope Imaging Spectrograph, on board the Hubble Space Tele...
متن کاملCoronagraphy with NICMOS
The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides a coronagraphic imaging capability in camera 2. NICMOS PSF-subtracted coronagraphy routinely results in per-pixel background rejections of ∼ 10 of an occulted target’s total flux density at an angular distance of 1′′, thus providing a highcontrast lever for the detection of close sub-stellar companions. At 1.1 μm (with an ...
متن کامل