Constellation Paper

Constellation Papers are an item found in shrine chests. When held, if there are undiscovered available constellations to the player holding the paper, it will fill in with an undiscovered constellation. If all constellations available to the player have been discovered, it will not fill in with a constellation.

When right-clicked, a filled Constellation Paper will display the constellation's name, shape and phases.

if the constellation can be used to attune a player or crystal, holding a Constellation Paper near an Attunement Altar structure will display blue particles where Spectral Relays should be placed if the player wants to set the altar to said constellation.

Trivia
Horologium and Pelotrio are the only constellations that do not show up during any particular moon phases. This is because Horologium appears once every 36 days and Pelotrio only shows up during very bright or very dark nights.