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