Light and Telescopes

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ACROSS
1. The ability of an optical device to distinguish fine detail in an image.
4. The _____ of light in a vacuum is constant: 300,000 km/s.
7. The color of light with the shortest visible wavelength.
9. The distance between one crest of a wave to the next.
13. The compression or shortening of waves due to the Doppler effect when an object is moving toward the observer.
15. Blue-jean blue.
17. A small lens used in both refracting and reflecting telescopes.
20. The lengthening of waves due to the Doppler effect when an object is moving away from the observer.
21. The bending of light as it passes from one material into another.
22. _____ radiation includes gamma rays, x-rays, ultraviolet, visible light, infrared, and radio waves.
23. A three dimensional parabola. A mirror of this shape can focus parallel light to point.
DOWN
2. _____ lines appear as bands or lines of bright colors when a hot glowing gas is seen through a spectroscope.
3. Radiation that has a wavelength that is just a little too short to be visible.
4. The range of electromagnetic radiation from gamma-rays through radio waves.
5. A _____ telescope has a mirror as its major element.
6. The color of light with the longest visible wavelength.
8. A transparent material that brings light to a focus.
10. _____ lines appear as dark lines in an otherwise continuous spectrum. Stars show _____ lines when seen through a spectroscope.
11. Radiation that is just a bit too long to be visible.
12. The larger of the lenses used in a refracting telescope.
14. An astronomer's description of the steadiness of the Earth's atmosphere.
16. This effect - a shift in wavelength - can be used to determine how an object is moving.
18. A _____ telescope has a lens as its major element.
19. Most of the radiation from space is blocked by this. It also limits earth-based telescopes' resolution.
21. The colors of the visible spectrum.

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