parallactic ellipse

American  

noun

Astronomy.

1. the apparent ellipse, as seen against the background of more distant stars, described annually by a nearby star because of the earth's orbital motion around the sun.

---

Example Sentences

It has been already pointed out how each star appears to describe a minute parallactic ellipse, in consequence of the annual motion of the earth, and by measurement of this ellipse the parallax—and therefore the distance—of the star can be determined.

From Project Gutenberg

At a certain date, which can be readily computed, the star is at one end of the parallactic ellipse, and six months later the star is at the other end.

From Project Gutenberg

The observations, therefore, failed to reveal the existence of a parallactic ellipse—or, in other words, the distance of Nova Cygni was too great to be measured by observations of this kind.

From Project Gutenberg

In the technical language of astronomers, we speak of this as the parallactic ellipse, and it is by measuring the major axis of this ellipse that we determine the distance of the star from the sun.

From Project Gutenberg

In a somewhat more popular manner, we would say that one thousand times the major axis of the very largest parallactic ellipse would not be as great as the diameter of the full moon.

From Project Gutenberg