You have been given a filepath to open. Open both asteroid pictures (the one from Chile and the one from elsewhere).

Be sure you have already identified your asteroid.

First we will align the images.

Click on the "Show Aligner" icon

Select both asteroid images in the dropdown menu.

Select either file in the "Reference Image File" drop down.

Note that it now says "Processing is complete."

Now we will stack the images.

Click the "Show Stacker" icon.

Select both asteroid images from the dropdown.

This has created a new image file with "-stack" in the name. Click on that image to display it.

You will see that the dot you had identified as your asteroid is now slightly oblong.

Zoom in on it until it fills your screen.

Click the up arrow next to "Saturation level percentile" repeatedly until your asteroid now looks like two separate dots.

Now you see the asteroid in two locations on the image. One of these is where the telescope in Chile saw the asteroid, the other is where the telescope elsewhere on Earth saw it at the same moment.

Click on one of the images of the asteroid.

Then click on the second image of the asteroid.

Scroll down and copy the measurement (in arcsec) between the two into your assignment.

Afterglow: Measure Asteroid Angular Shift