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Home Q & A Board Science-Related Homework Help Physics Astronomy
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Atir Atir
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6 years ago
The _______________ time is the amount of time it took light to travel from a celestial object to Earth.
 
  Fill in the blank(s) with correct word

Question 2

Why are reflecting telescopes cheaper to build than refracting telescopes?
 
  What will be an ideal response?

Question 3

_______________ are objects of known luminosity used for finding distances.
 
  Fill in the blank(s) with correct word

Question 4

One way to measure and compare the strength of the radio signal at various places in the sky is to produce a(n) _______________ in which each color marks areas of similar radio intensity.
 
  Fill in the blank(s) with correct word
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Replies
wrote...
#1
6 years ago
Answer to q. 1

lookback
look-back

Answer to q. 2

Mirrors are much less expensive than lenses because light reflects off the front surface; therefore, only the front surface of a mirror needs to be made with a precise shape. Lenses are much more difficult to manufacture than a mirror of the same size. The interior of the glass must be flawless and pure, and must be made of two different kinds of glass requiring four precisely ground surfaces. Refracting telescopes larger than 1 m would be prohibitively expensive.

Answer to q. 3

Standard candles

Answer to q. 4

representational-color image
representational-color map
false-color image
false-color map
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