GALILEAN TELESCOPE How to Build It

Structure: TWO LENSES OBJECTIVE just outside The object being viewed is placed just outside the focal length of the objective lens. Image is real, inverted, and enlarged EYEPIECE Magnifying glass, used to view the real intermediate image formed by the objective lens. Image at the focal point of the eyepiece. Shorter focal length = larger the magnification.

Use lasers and microscopes to see molecular alignment

Detector and feedback electronics Laser Photodiode Sample Surface Scanner Cantilever and Tip z-scanner xy-scanner Scan a sharp ‘tip’ over surface Vertical bending due to forces on tip detected by laser Laser focussed on back of cantilever Laser spot reflected to photodiode Photodetector signal  feedback circuit  z-part of scanner Z-movement  topography

J. Chem. Phys. 139, (2013) Form polymer nanowires in solution Well-ordered nanowires minimise disorder when blending to make solar cells Polymer domains, 10s of nanometres across, are visible in AFM images Solar cell device efficiency increases 10 x

BRIGHTENSHARPENMAGNIFY

Telescope with front + back lens = “refracting” telescope Use lenses to concentrate light Lenses are made of glass

Refracting telescope at the Yerkes Observatory It’s the largest refracting telescope in the world Making glass lenses this large is really difficult!

Chromatic aberration Spherical Aberration Increased refraction of light rays when they strike a near its edge vs. those at the centre Lens is unable to bring all wavelengths of colour to the same focal plane

1672: Issac Newton developed a telescope that used a curved mirror instead Problem: Any lens acts like a prism >> splits light into colours >> haloes “Newtonian Reflectors” can be much smaller Two Polished Mirrors Light hits spherical mirror one Reflects into telescope tube Light hits flat second mirror (45 degree tilt) Reflects into eye

Largest reflecting telescope in the world On top of a volcano in the Canary Islands “Gran Telescopia” which means “Big Telescope” €130 million Focal length – m 10.4 m

Focal Point VEX CONVEX

CAVE CONCAVE

STEP 1 Test your lenses Follow the instructions to find out what the properties of your lenses are.

STEP 2 Assemble two tubes that can telescope (one just fits into the other) Make lens holders (two - one for each lens).

STEP 3 Follow the instructions to assemble the pieces. The small lens is for your eye (the eyepiece lens). The big lens should point at the object (the objective lens).

TEST IT!

Test

GALILEAN TELESCOPE How to Build It