Tools for Observation

Human Eye

• CORNEA - The transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea is an essential part of the focusing in your eye.

• PUPIL - The variable-sized, black circular or slit shaped opening in the center of the iris that regulates the amount of light that enters the eye.

• LENS - A transparent, biconvex (lentil-shaped) structure in the eye that, along with the cornea, helps to reflect light to be focused on the retina.

• RETINA - A thin layer of neural cells that lines the back of the eyeball. It is comparable to the film in a camera

• OPTIC NERVE - The nerve that transmits visual information from the retina to the brain.

• Source: www.wikipedia.com

The retina• Rods detect light

and dark• A cones detects

either Red, Blue, or green

• Cones concentrated at the center

• Rods at outside of eye

Cone sensitivity

Ha, Ha! Visible Spectrum of Light!!!

Humans have developed tools to see things better….

• Galilean Telescope

Camera

Space Telescopes

• Hubble Space Telescope (HST)

Trapezium (Orion nebula): Hubble Space Telescope

Telescope, Cassini: Moon

Yellow filter, digital camera, 6’’ telescope: Sun

Mars as seen by HST

Star forming region in the Large Magellanic Cloud (LMC) from HST

Film camera, 800mm lens: Comet Swan

HST, M31 (Andromeda galaxy)

Bullet Nebula (HST Chandra X ray)• Is this a “true color” image?

• Why was this image taken as an “X ray” photo?