At night, an observatory near Prague was surrounded by a squad of fully armed guards. Two people stood on the platform: one was Emperor Rudolf II, and the other was Kepler, the famous astronomer, physicist, and mathematician.
Due to his almost fanatical love for astrology, Rudolf II maintained close ties with astronomers Tycho Brahe and Johannes Kepler, successively appointing them as royal astronomers to compile star charts, indirectly making immense contributions to scientific development.
This was arguably one of the most significant achievements in the Emperor's short life. Kepler's "Rudolfine Tables," compiled in his later years, were named in honor of his former patron, Rudolf II.
Rudolf II had set out from the palace early, arriving at the observatory in high spirits. The bright moon hung in the sky, but hardly any stars were visible, almost all obscured by thick clouds. Even with the observation instrument invented by Tycho Brahe, only faint starlight could be seen beneath a cloud, barely allowing for angle and directional readings.
For Kepler, this was enough. His purpose was observation, not stargazing, and he observed with great enthusiasm. However, such weather conditions were not as favorable for Rudolf II, who was only half-interested.
After standing idly by for a long time, Rudolf II finally couldn't help but ask, "Kepler, did you truly invite me to observe the stars, or to admire the moon?"
Only then did Kepler remember that he wasn't observing alone today; he had also invited Emperor Rudolf II.
Years of living under others' patronage had smoothed the rough edges of the young genius Kepler, but when immersed in his research, he still easily overlooked everything and everyone around him, even his benefactor. Once he started observing, Kepler almost forgot the true purpose of inviting Rudolf II today.
"It's for stargazing, is there a problem? Were you just admiring the moon the whole time?" Kepler reluctantly pulled his eyes away from the observation instrument and teased him in a respectful tone.
Rudolf II felt a bit embarrassed and complained angrily, "The clouds are so thick, I can't see anything at all!"
"How can that be? You can see them! Look, that's Mars," Kepler said, pointing to a faint light in the sky, then moved his finger and continued, "That moving one over there is a comet, and that one is..."
"I can't see anything. Next time, don't call me for this kind of weather. You can look by yourself," Rudolf II interrupted Kepler, both anxious and annoyed.
Kepler waved his hand, feigning helplessness, "Oh, if only there were an astronomical telescope that could clearly observe stars regardless of the weather conditions."
"But there isn't, is there? Why don't you invent one?" Rudolf II blurted out without thinking.
"I do have that idea," Kepler said, seizing the opportunity.
Upon hearing this, Rudolf II immediately became interested. "Oh? If you have an idea, go for it! How would you do it? Tell me quickly."
Seeing that the fish had taken the bait, Kepler slowly explained, "You make it with two convex lenses, meaning both the objective lens and the eyepiece are convex lenses. The image formed is inverted, the objective lens has a small magnification, and the eyepiece has a large magnification. This structure easily achieves high magnification, has a longer tube, and a wider and more distant field of view."
Rudolf II understood every word, but when those words were strung together, he had no idea what Kepler was talking about.
To cover up the embarrassment of not understanding anything, Rudolf II changed the subject and asked, "Have you tried it? Is it feasible?"
"I want to try, but I haven't yet," Kepler replied truthfully.
"Try it! Why don't you try?" Rudolf II seemed even more eager than Kepler for the astronomical telescope to come into being.
Kepler looked troubled and said, "There's no more funding. And my salary for the past few months hasn't been paid; my family is almost out of food."
"What? They dare to withhold your salary? That's outrageous! I'll go back and make them pay you immediately."
"Thank you, Your Majesty," Kepler said happily, but not content with just that, he then reminded him, "What about the funding..."
"Funding..." When funding was mentioned, it was Rudolf II's turn to get a headache. For the past few months, everyone had been saying there wasn't enough money, and the Holy Roman Empire was already heavily in debt.
Funding was different from salary, which should be paid. How much Kepler would need for the astronomical telescope was an unknown; it could easily be a bottomless pit. He himself was willing to spend the money, but the various ministers might not accept it, and who knew what kind of uproar it would cause then.
"Alas, you must know that the country is at war now, and money is scarce everywhere. If you need too much funding, I might not be able to make the decision. I'll try my best to fight for it for you, and you should also try your best to overcome the difficulties and see if it's possible." Rudolf II's expression was slightly bitter; how had he become such an Emperor?
"Alright, thank you, Your Majesty. I will do my best," Kepler sincerely thanked him. He was already very satisfied to receive such a reply. Kepler knew that Rudolf II's words were not an excuse; he truly couldn't make the decision.
"I hope I'm still alive when you invent this astronomical telescope," Rudolf II sighed, looking up, as if he had foreseen something.
"You will surely live a long life," Kepler flattered him.
"Because astrology yielded results, and constellations affect my lifespan, I changed Cancer to Taurus. I don't know if that will work," Rudolf II seemed to be asking Kepler, and also talking to himself.
"Well, since I'm already here, help me with an astrological reading. What will be the outcome of our war with the Ottoman Empire?"
Kepler himself did not believe in astrology, a pseudoscience. In his book "On the More Reliable Foundations of Astrology," published in 1601, he disagreed with the idea that celestial bodies determine human destiny and was skeptical of astrology: "If astrologers sometimes get it right, it should be attributed to luck."
However, forced by necessity and to cater to the Emperor's preferences, one of his main tasks was to perform astrological readings for the Emperor, a profession he pursued throughout his life. Over 800 astrological charts were preserved in his posthumous papers, making Kepler a true astrologer.
After some operations, Kepler confidently told Rudolf II, "Your Majesty, I have just performed an astrological reading, and we will definitely achieve ultimate victory!"
"Really? That's wonderful! Then I must withstand the pressure, ignore those cowardly fellows, and persist in continuing the war! The Ottoman Empire is under attack from both front and back, and the Pope's reinforcements will arrive soon. Victory must not be far off! Kepler, don't you agree?" Rudolf II asked excitedly.
"It will certainly be so, Your Majesty."