Prague Celestial Project — Astronomers at the Edge of the Void

The departure chart is finished, but its three authors refuse to sign it. Kepler’s calculations send the aethership to a deserted station, Copernicus places it near another planet, and Tycho Brahe insists the telescope has been tampered with. A court officer has already announced the hour of launch.

What Is Happening Right Now?

Ladislaus the Posthumous wears the Bohemian crown in 1454, while George of Poděbrady commands much of the machinery of government. Both households want the project’s discoveries. The scholars have the instruments to measure faraway worlds but cannot make a vessel safe merely by agreeing on where it must go. A damaged orrery points to a passage that appears only on certain dates.

Places and People

The Star Chamber

Measurements taken through long sighting tubes are corrected against returned logs. Two assistants have produced identical figures from different instruments, which should be impossible if one telescope is defective.

The Sealed Workshop

An incomplete aethership undergoes pressure and propulsion tests. Leonardo’s mechanical sketches are being compared with designs obtained from an older vault.

The Physician’s Room

Paracelsus examines the illness of a returned crewman, studies stale air and contaminated water, and refuses to declare the next voyage safe without a full examination.

Rivals and Bargains

Kepler, Copernicus and Tycho Brahe disagree without becoming enemies. Their dispute is about reliable proof. Galileo exchanges new observational reports from Italy; Ming officers offer instruments in exchange for navigation data. Richelieu’s buyers pose as scholarly patrons, while a Bohemian faction would rather conceal the project than allow its rival to claim success.

Instruments Before Voyages

The Prague project starts at a desk crowded with astronomical tables, engraved brass circles, sighting tubes, geared models, astrolabes and instruments made for measuring angles. Alchemists study coatings and protective workings; craftspeople fit sealed doors and test enchantments that can keep air within a vessel. Its smaller experimental ships are difficult to reproduce and sometimes too fragile for the journeys their patrons demand. Ordinary canvas sails and terrestrial compasses are of little value in vacuum unless an enchantment gives them a new function.

Destinations Worth Measuring

The Moon: a close test of the observatory’s calculations. A return voyage bearing its own measurements of the surface would settle arguments that have lasted years. One observer proposes a protected platform; another wants to inspect a pattern in the rock that changes whenever the planet’s shadow falls across it.

Venus: the bright morning and evening star, valued for astronomical observation and the study of unfamiliar atmospheric effects. The crushing heat below its clouds rules out ordinary surface visits. A carefully suspended or moving observatory high above the surface might survive long enough to report its observations, but it still needs air, reliable altitude control and a way to return.

Mars: an ambitious later destination. Prague’s scholars wish to test accounts of ancient water and determine whether a copied star map describes the right planet at all. A dangerous expedition is justified only if the patrons will finance the journey home.

The Price of a False Measurement

Ladislaus’s court seeks distinction, while George of Poděbrady’s supporters need results that can be repeated. An instrument maker who admits a miscalculation may save a crew and lose a patron. A scholar who hides an error can send a vessel towards empty space. The project advances through observation and difficult workmanship, not by possessing knowledge or machinery centuries ahead of its time.

Three Journeys

The Missing Interval

Find an old observation book recording the period during which a gate appears. The missing pages were removed by someone who understood their value.

A Crewman’s Testimony

Protect a sick pilot whom two court authorities wish to question separately. His scars match the markings on an alien device.

The Wrong Launch

Stop a vessel from departing under a forged court seal before the navigator notices the substituted chart.

Travel Beyond Earth

An instrument proves where a target lies, not whether a vessel carries enough air and water to reach it. A successful outward journey without a safe return remains a failure. Enchanted gates may cross the distance more quickly, but their keepers and destinations are often unknown.

Connected Places and People

Prague · Kepler · Copernicus · Tycho Brahe · Spacefaring Powers of 1454 · Outer Space Terrain

History and Sources

The people, political events and timelines of 1454 follow the linked regional histories. The celestial programme is part of this world’s history; the routes, physical hazards and distinctions between planets and planes follow the Space Atlas, Solar System and Timeline.