1 / 6

SwissCheesEx

SwissCheesEx. An idea to obtain over-diffraction limited imaging with a seeing limited, extremely large telescope over a wide range of wavelengths. A. Richichi - Garching Science Day 2006. Lunar Occultations. The Moon’s limb acts as a straight diffracting edge.

anoush
Download Presentation

SwissCheesEx

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SwissCheesEx An idea to obtain over-diffraction limited imaging with a seeing limited, extremely large telescope over a wide range of wavelengths A. Richichi - Garching Science Day 2006

  2. Lunar Occultations The Moon’s limb acts as a straight diffracting edge. The diffraction phenomenon occurs in “vacuum”, no turbulence effects. High-angular information is embedded in the diffraction fringes. The “resolution” is independent from telescope diameter (but depends on signal-to-noise ratio). Temporal scales (depending on wavelength and apparent limb velocity ) are ~0.1s. High temporal rates are needed, typically ~1 ms in the near-IR. Diffraction patterns of two or more components add linearly.

  3. Why Lunar Occultations are good • Simple, economical (also in time) • High angular resolution (0.5-1 mas) • Sensitive (on a large telescope) Why the are not good enough • Cannot choose the source • About 10% of sky covered by the Moon (in 18.5 years) • One-dimensional scan only

  4. Artificial Occultations using Giant Sails • Choose your own targets / time • Repeat observations • High sensitivity (no background) • Tomographic Imaging (Swiss Cheese)

  5. Why an ELT? Sails should be as large as possible, but won’t be as large as the Moon They have to be very close to Earth to have a decent angular coverage They will have a high angular speed to remain in a stable orbit Integration times will have to be correspondingly short Short wavelenths (not hitherto possible) will also require short integration times Telescope area is critical to set the limiting magnitude (not its optical quality)

  6. Financial support from Swiss Cheese Producers? What can you do with a Swiss Cheese in Space? Assume 42m ELT, 1000km Ø sail, 0.05m/ms (P ~1 yr) K mag ~ 17, 0.5 mas (eq. to 800m). Also B, V 2º (16x Moon area) Full imaging in few hours 30m vs 42m: also OK, same angular resolution, 0.4mag loss Perfect coronograph, direct detection of exoplanets Showstoppers/Difficulties Build, deploy and control large sail?? Orbit must be low, slow, provide sky coverage Non-Fresnel diffraction requires ad-hoc analysis

More Related