1 / 9

An all-sky heliospheric imager

An all-sky heliospheric imager. All-sky coverage (when two are employed) 0.1% differential photometry Robust, light-weight design Low background-light contribution When bright background-light contributors are kept away from FOV and optics do not protrude from protected volume.

brie
Télécharger la présentation

An all-sky heliospheric imager

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. An all-sky heliospheric imager All-sky coverage (when two are employed) 0.1% differential photometry Robust, light-weight design Low background-light contribution When bright background-light contributors are kept away from FOV and optics do not protrude from protected volume

  2. Basic concept – see models here • A smooth corral blocks stray light from background sources below FOV • Light must multiple-diffract over surface to reach protected volume • Non-protruding optics provides a virtual image of a hemisphere of sky • A conventional CCD camera views virtual sky • Two such cameras placed on opposite sides of a spacecraft provide whole-sky coverage

  3. Corral concept: laboratory tests

  4. Principal corral features • Lightweight, simple, robust (resembles a foxhole rather than a castle…) • Does not depend upon high-tech surfaces, nor is surface performance subject to normal contamination • Precise alignment is unnecessary when corral surface extends a bit beyond minimum required • ~ 1 m size permits viewing within 2° of Sun

  5. Principal optics features • Non-protruding design • Toroidal mirror covers most of sky • That portion of sky occulted by mirror separately covered by lens in center • Virtual image of sky recorded by conventional CCD camera system • Stray light residue controlled by field stop, Lyot stop and final imaging system

  6. Cutaway schematic of corral/optics (left)Conventionally turned optic (right)

  7. Hemispherical-Imager Mirrors A diamond-turned lightweight mirror has been fabricated with the tool moving in a circular path, that avoids the “jaggies” that ordinarily plague such strongly curved mirrors. Manufactured by Bach Research, who also made the SMEI diamond-turned mirrors. Conventionally turned & polished Diamond-turned

  8. Schematic optics cross-section

  9. Mirror interior design

More Related