Universe 2

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Across
  1. 4. Moon phase after full
  2. 9. Emission of energy as waves
  3. 10. All matter and space; everything
  4. 13. Force of attraction
  5. 15. Natural satellite
  6. 16. Particles without charges
  7. 18. Illumination from stars
  8. 19. A small body resembling a planet
  9. 20. Distance between crests of a wave
Down
  1. 1. Instrument of galactic observation
  2. 2. Curved path of a celestial object
  3. 3. Longest and shortest days
  4. 5. Place of astronomy
  5. 6. A space devoid of matter
  6. 7. A point at which infinite value is reached
  7. 8. Belt of the heavens divided into signs
  8. 11. Degree of brightness of a star
  9. 12. Iconic part of your favorite planet :)
  10. 14. Aspect of illumination
  11. 17. Range of wavelengths