An all sky heliospheric imager
Download
1 / 9

An all-sky heliospheric imager - PowerPoint PPT Presentation


  • 114 Views
  • Uploaded on

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.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' An all-sky heliospheric imager' - brie


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
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


Basic concept see models here
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



Principal corral features
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


Principal optics features
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


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


Hemispherical imager mirrors
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




ad