Light, Optics and Telescopes Trip to Lick Observatory

Imaging: what you care about
• Aperture size: light collecting area
! larger diameter telescopes can see fainter objects
• Angular resolution: how much angular detail you can see
! larger telescopes have better angular resolution
! but blurring by sky is usually the limiting factor
• Field of view: how much of the sky you can see at once
! depends on design of telescope (“plate scale”)
! size of your detector
Large telescopes collect more light…
• Telescope funnels light to camera
! the larger the aperture, the more light collected
35mm camera at
“prime focus” on
a Schmidt-Cassegrain
telescope