Refracting
Refract means:
to bend
Pure reflecting telescopes use ___________ instead of lenses.
mirrors
Find the magnification of a 100 cm focal length objective lens with a 2 cm eyepiece.
50x
How much more light does a 20 cm lens gather than a 10 cm lens?
4x
Galileo famously discovered the Galilean Moons, which are moons of
Jupiter.
Refracting telescopes suffer badly from ______ ________, which is a color distortion.
chromatic aberration
Why would a reflecting telescope be more advantageous than a refracting telescope for observing very faint, distant galaxies?
Reflecting telescopes can be made much larger, gathering more light
You use a magnifying glass with a focal length of 20 cm. What is the magnification?
1.25x
How much more light does a 20 cm diameter telescope gather than a 15 cm telescope?
1.78x
Why do space telescopes like Hubble produce clearer images than even the largest ground-based telescopes?
They avoid atmospheric turbulence and distortion
A student observes that their refracting telescope shows Saturn upside-down, but their friend's reflecting telescope shows it as a mirror image. What explains this difference?
Different optical designs create different image orientations
Reflecting telescopes produce am image that is _____________ than an equally-sized refracting telescope. (brighter/darker)
Darker
A telescope has a focal length of 1500mm and you want 75× magnification. What eyepiece focal length do you need?
20 mm
How much more light would a 15-inch diameter telescope collect compared to a 5-inch diameter telescope?
9x more
Why might an astronomer choose to use a radio telescope instead of an optical telescope to study a particular celestial object?
The object might be hidden by dust clouds that block visible light. The object may only emit radiation in the radio frequency range.
How many lenses does a basic refracting telescope have?
2
Telescopes that are a mix of reflecting and refracting are called __________ ___________.
compound telescopes
What is the focal length of a magnifying glass that makes an image look 4.5x larger?
5.55 cm
Why is aperture (diameter) more important than magnification when choosing a telescope for deep-space observation? (2 reasons)
Larger aperture provides better light-gathering power and resolution
How did Galileo's telescope observations challenge the scientific understanding of his time?
He discovered that celestial objects had detailed features and were not just dots of light
The reason our refracting telescope had a mirrored image instead of a flipped image is
the diagonal flipped it back.
The __________ Space Telescope (launched 1990) and the _______ _________ Space Telescope (launched 2021) are examples of advanced reflecting space telescopes.
Hubble, James Webb
What is the objective lens focal length of a telescope with a 4 mm eyepiece and 200x magnification?
800 mm
How big would a lens need to be to increase the light gathered by a 10 cm lens 6 times?
24.5 cm
Who invented the very first telescope, and when?
Hans Lippershey, 1608