Hints: Observatory

Getting started:

The observatory tracks stars from year to year, particularly from 2018’s GPH website to now. The stars move in a straight line from point A to point B.

Hint 2:

You can completely ignore the stars that stayed put. Grouping the 45 stars that moved into nine groups of five is a good idea. You can consider each group independently. It may be helpful to consider the two images overlaid on each other.

Hint 3:

The observatory tracks the how much of the way the stars are from their destination, for example, whether a star is a third or a half of the way there. Track each star’s progress to their destination.

Hint 4:

Consider the ratio of the length of each star from the 2018 image to the corresponding star from the puzzle on the same line. These are all N/27 for some integer N.

Hint 5:

Convert A=1 Z=26.

Hint 6:

The 5-letter strings are missing a letter.

Hint 7:

There are two cluephrases in this puzzle, which should narrow down the answer to just one possibility. Perhaps reconsider a particular assumption that you may have made when getting the ratios?