Definition

1. Noun:
   • Parallax: The apparent displacement or difference in the apparent position of an object when viewed along two different lines of sight. It is measured by the angle or semi-angle of inclination between those two lines.
   • In astronomy, it is a crucial method for measuring distances to nearby stars.
   • In photography and cinematography, it refers to the misalignment between the viewfinder and the camera lens, causing the captured image to differ slightly from what was framed.

Usage Examples

• Noun:
  • Thị sai là một công cụ quan trọng trong thiên văn học để đo khoảng cách. (Parallax is an important tool in astronomy for measuring distances.)
  • Máy ảnh này có vấn đề về thị sai, nên hình chụp bị lệch. (This camera has a parallax issue, so the photo is misaligned.)
  • Các nhà khoa học tính toán thị sai hàng năm của ngôi sao. (Scientists calculate the annual parallax of the star.)

Advanced Usage

• "Thị sai thiên văn" (Astronomical parallax): Specifically refers to parallax used for celestial measurements, such as stellar parallax or heliocentric parallax.

  • Thị sai thiên văn giúp xác định khoảng cách đến các ngôi sao gần. (Astronomical parallax helps determine distances to nearby stars.)

• "Thị sai ảnh" (Parallax error): Often refers to the error or effect caused by parallax in imaging or measurement devices.

  • Khi đọc số trên đồng hồ, tránh thị sai ảnh bằng cách nhìn thẳng. (When reading the gauge, avoid parallax error by looking straight on.)

Variants and Related Words

• Hiệu ứng thị sai (n): Parallax effect. Often used in visual media (e.g., web design, video games) to create an illusion of depth.
  • Trang web sử dụng hiệu ứng thị sai khi cuộn chuột. (The website uses a parallax effect when scrolling.)

Synonyms

• Parallax: The direct equivalent in scientific and technical contexts.
• Displacement: Can be used in a general sense to describe the apparent shift.
• Viewing error: A simpler term for the photographic/cinematic context.

Related Scientific Concepts

• Thị sai hàng năm (Annual parallax): The angle subtended by 1 astronomical unit at the star's distance, a key unit (the parsec) is derived from it.
• Thị sai địa lý (Geocentric parallax) or Thị sai nhật tâm (Heliocentric parallax): Classifications based on the observation point (Earth or Sun).