Times, Sunday Times (2010) His caustic comments make wonderful copy, of course. Times, Sunday Times (2009) But over ten years, audiences have become less able to accept her caustic humour. The Sun (2010) Doctors feared she would die from horrific injuries caused by the 98 per cent strength caustic soda.
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
The parallax angle is measured from observations of the nearby stars motion relative to distant background stars. Astronomers can make this measurement using photographs taken with the telescope. They can measure the angle of the nearby star's motion because they have previously calibrated the angle subtended by the field of view of the telescope.