However, near the center of the image, four bright points moved together against the background stars.

Three nearby candidates were all found to be background stars.

With high enough temporal resolution even the angular size of the background star can be determined.

And yet the pod wasn't moving at all; the background stars were rock steady.

The other side was a black silhouette, visible only because it eclipsed the background stars.

If the background star is off the line of sight, you'll see two images.

They can be seen as dark clouds against bright emission nebulae or background stars.

They shouldn't drift against the background stars, not at all.

Still, Conrad had become well familiar with the image during training, and could pick it out now against the background stars.

In an hour then, it will move about half a degree, roughly its own diameter, with respect to the background stars and the Sun.