Task 1 of 6

Note: It is highly recommended that your read the Introduction before you start at this exercise.

The first goal is to calculate the angular diameter of the ring, that is the apparent diameter of the ring in arcseconds, as observed from Earth. This is the angle a.

The relative positions of stars 1, 2 and 3 in the image of SN 1987 (see the applet to the right), are given as angular separations (in arcseconds) in the data table below.

Connect these values with the direct measurements on the image to determine the scale of this image (in arcseconds/pixels).