heliacal

/hi:'laiəkəl/

Thân thiện

The heliacal rising of Sirius marks the start of the ancient Egyptian new year.

Definition

1. Adjective:
   • Pertaining to or near the sun: Relating to the sun or its proximity.
   • Specifically, relating to the first or last visibility of a celestial body with respect to the sun: In astronomy, used to describe the first rising of a star or planet just before sunrise after a period of invisibility, or its last setting just after sunset before becoming invisible, due to its conjunction with the sun.

Usage Examples

• Adjective:
  • Ancient Egyptian calendars were based on the heliacal rising of Sirius.
  • The heliacal setting of Venus was observed by the priest-astronomers.
  • The heliacal year is measured from one such rising of a star to the next.

Advanced Usage

• "Heliacal rising": The first appearance of a star or planet in the eastern sky just before sunrise, after a period when it was too close to the sun to be seen.
  • The heliacal rising of the Pleiades marked the beginning of the agricultural season for many ancient cultures.
• "Heliacal setting": The last appearance of a star or planet in the western sky just after sunset, before it becomes lost in the sun's glare.
  • They recorded the heliacal setting of the constellation to predict seasonal changes.

Variants and Related Words

• Heliacally (adverb): In a heliacal manner; with reference to the sun.
  • The star rises heliacally in mid-July.
• Heliac (adjective, rare/archaic): An older, less common variant of "heliacal."

Synonyms

• Solar: Of, relating to, or determined by the sun. (Note: "Solar" is a broader, more common term, while "heliacal" is specific to astronomical visibility.)
• Sun-related: Pertaining to the sun.

Related Phrases

• "Heliacal year": A year defined by the interval between successive heliacal risings of a specific star, such as the Sothic year in ancient Egypt.
  • The heliacal year of Sirius is approximately 365.25 days.
• "Heliacal phase": The period or event of a star's heliacal rising or setting.
  • The monument is aligned with the heliacal phase of a bright star.

Học thuật

Adjective

1. pertaining to or near the sun; especially the first rising of a star after and last setting before its invisibility owing to its conjunction with the sun
   • the heliacal rising of the Dog Star
   • the heliacal or Sothic year is determined by the heliacal rising of Sothis (the Egyptian name for the Dog Star)

Từ đồng nghĩa

• heliac