Definition

1. Noun (Astronomy):
   • Elongation: The angular distance between a planet or other celestial body and the Sun, as observed from Earth. It describes how far the object appears to be from the Sun in the sky.

Usage Examples

• Noun:
  • Li giác của Sao Kim tối nay rất lớn. (The elongation of Venus tonight is very large.)
  • Các nhà thiên văn đo li giác để xác định vị trí của hành tinh. (Astronomers measure elongation to determine the planet's position.)
  • Hành tinh đó đạt li giác cực đại vào ngày mai. (That planet will reach maximum elongation tomorrow.)

Advanced Usage

• "Li giác cực đại" (Maximum elongation): The greatest angular separation between a planet and the Sun, which is the best time to observe the planet in the evening or morning sky.
  • Sao Thủy sẽ đạt li giác cực đại phía đông vào tuần tới. (Mercury will reach its greatest eastern elongation next week.)

Variants and Related Words

• Góc li giác (n): elongation angle. This phrase is sometimes used interchangeably with "li giác."
  • Góc li giác được tính bằng độ. (The elongation angle is measured in degrees.)

Synonyms

• Angular separation: A more general term for the angular distance between two celestial objects.
• Elongation: The direct and most precise equivalent in astronomical terminology.

Notes on Usage

• Technical Term: "Li giác" is a specialized scientific term used almost exclusively in astronomy. It is not used in everyday conversation.
• Context is Key: This word will only be encountered in texts or discussions about astronomy. It is typically modified by adjectives like "lớn" (large), "nhỏ" (small), or "cực đại" (maximum).