Question

In the demonstration, 360∘ of rotation (one full rotation) represents a sidereal day. You can actually measure the length of the sidereal day by measuring the time from when __________ crosses your meridian on one day (or night) until it crosses the meridian on the next day (or night).

Check all that apply.
the star Sirius
the star Vega

Answer 1

Both stars Sirius and Vega are correct options

Step-by-step explanation:

A sideral day passes when a star gives one full rotation of the earth about its axis so that the distant stars appear in the same position in the sky. Is the time it takes a star to return to its original position, therefore we can take both Sirius and Vega stars (and any other star) to measure the lenght of the sideral day, it doesn't matter which one as long as its measured correctly with the meridian or the point took as reference.