Seven young people from the two academies, plus Sun Yunqiu who was called to accompany them, gathered in distinct groups during the break.
There are four Hanlin academies in one pile and four Qintian academies in one pile.
Li Quan, a sunny boy, sat down on the ground and asked: "Brother Yuan Jing, haven't you built your navigation clock yet?"
Wang Su, named Yuanjing, is a graduate student at Jinling University and a disciple of Fang Yizhi of Qintian Academy. He majors in physics, minors in astronomy, and is proficient in mechanics. His appearance is not impressive.
Appearance is the key. Even if they are not married, they are already engaged, so it is difficult to find someone who meets the emperor's requirements, so Wang Su, who is relatively ugly, is also brought in to fill the role.
Wang Su complained endlessly: "Brother Yuheng, the precision you require is too high. How can I make it? I have been struggling for more than three months, and I have only reduced the clock error by 3%-8%. I will probably die of old age."
On that day, I couldn’t even build a marine clock for you.”
"Try again, haha, you can definitely do it." Li Quan was not discouraged and gave Wang Su a shot of chicken blood with a smile.
Tian Yang said: "Brother Yuheng, if you want to measure longitude at sea, why do you have to use the clock method? Can't you use the lunar distance method?"
Li Quan shook his head: "The shortcomings of the lunar distance method are too obvious. First, it cannot be used on rainy days or during the day; second, there are always a few days in each month when measuring longitude using the lunar distance method will produce deviations; third
Third, the calculation amount of the lunar distance method is too large, and it may be difficult for the star guide on the ship to master it."
Tian Yang looked dull in front of the princess, but he spoke very eloquently at this moment: "The ocean voyage lasts for a year and a half. The first and second shortcomings you mentioned can be completely ignored. As for the calculation amount that is too large, we can make the lunar distance
Tables are used to prepare a lot of data in advance. The star guide can calculate according to the tables, which can greatly reduce the amount of calculations. By then, only high school graduates will be able to do it."
Sun Yunqiu listened for a while and asked curiously: "Are you talking about sailing?"
Sun Yunqiu is a master's degree from Qintian Academy, while the other three are not even bachelors, but are just graduate students affiliated with Qintian Academy.
Li Quan was still sitting on the ground, cupped his hands and said: "Master Sun knows that the three of us are discussing how to solve the longitude measurement during navigation. Today's maritime latitude measurement technology is very mature, but the longitude measurement has not been solved. If
If a ship cannot dock for a long time, it must calculate its longitude, otherwise it can only sail forward by chance."
"Tell me what you think." Sun Yunqiu became interested.
Li Quan said in detail: "There are two theories now, one is the clock method and the other is the lunar distance method. Let's talk about the clock method first. According to the movement of the earth around the sun, the time at different longitudes is different. The Qintianyuan Planetarium has
Set the longitude of Nanjing as 0 degrees. By calculating the time difference between the location of the ship and Nanjing, the specific longitude of the ship can be calculated."
Sun Yunqiu also knows how to make clocks. He immediately shook his head after hearing this: "The clock method is temporarily impossible to implement. The error is too large. The current clocks are simply not accurate enough."
Li Quan said: "My idea is to improve the accuracy of clocks as much as possible and build more marine clocks. Put ten or twenty marine clocks on the ship, and when measuring longitude, take the average of these marine clocks."
"No, no, you are trying your luck." Sun Yunqiu shook his head.
Li Quan added: "Then we can only use the lunar distance method. Use the position of the moon in the starry sky, treat the starry sky as a clock face, and use the moon as a pointer. Then through calculation, convert the moon's position into the time of the ship's location.
This method requires comparing star catalogs and relying on long-term observation data from observatories. Starry sky observation data is our strength. There are hundreds of years of data from Nanjing and Beijing. But the shortcomings are also obvious. It cannot be measured on cloudy and rainy days.
The error is very large in a few days. The main reason is that the amount of calculation is too large, which is difficult for ordinary navigation star guides to complete."
Wang Su added: "The shaking of the ship's hull also greatly interferes with the lunar distance method."
"It's not very big, it's very big, so I prefer the watch method." Li Quan said.
Wang Su said: "We plan to improve the celestial ruler and the cross to create more precise navigation instruments. But no matter how we improve it, if we want to measure longitude, we must know where the ship is."
To use a sextant to measure longitude, the prerequisite is to know the local time.
The European side is also thinking of ways. Since their astronomical observation data is insufficient, they have adopted the clock method for a long time. Since the error of marine clocks is too large, they should bring more marine clocks.
But marine clocks are precision instruments. Even in a few decades, the cost of each marine clock will be more than 500 pounds. Twenty marine clocks will cost 10,000 pounds.
Therefore, after the astronomical data in Europe matured, with the invention of the sextant and the accompanying "Lunar Distance Table", marine clocks were eliminated. Even so, measuring longitude took several hours. Until 1766, Mascarene
Hire a large number of "human computers" to list the relationship between lunar distance and longitude, and then shorten the longitude measurement time to 30 minutes.
"Are you planning to explore the ocean?" Sun Yunqiu asked.
Tian Yang pointed at Li Quan: "I don't want to go, but he wants to go."
Li Quan chuckled and said, "I can't wait any longer. I'm going to sail around the world."
Even if you are sailing around the world, there are mature routes now, and it is not necessary to calculate the longitude. Only when exploring around the world, calculating the longitude is necessary to cope with unexpected events.
Sun Yunqiu said: "I really can't help with other things. But to improve the cross, I have an idea, which is to install a telescope on the cross. Well, if you want to make more precise measurements, a cross will definitely not work.
.If you still want to use the lunar distance method, the measuring range of the instrument must be above 90 degrees. Then make the instrument 60 degrees and the measuring range 120 degrees. It is better to call it a 'sextant'."
Li Quan was very interested and asked: "What is the use of installing a telescope on an instrument?"
Sun Yunqiu said: "My idea is to use a telescope instead of naked eye observation, and then make a translucent mirror to make it a fixed horizon mirror, and then make a movable reflector. Rotate the reflector to make the celestial body align with the horizon or sea level.
The lines coincide. In this way, the angle of the reflector can be read to read the altitude angle of the celestial body..."
As soon as these words came out, the three of them suddenly became enlightened.
Tian Yang exclaimed: "Why does Master Sun have such wonderful ideas?"
Sun Yunqiu said: "I often use telescopes to observe stars. Many times I don't want to make calculations too troublesome, so I just think about some instruments that can simplify it."
The sextant was not originally used for navigation, but for observatory observations. The concept was proposed by Hooke and Newton. Because this thing was easy to use, it was shrunk by navigators and used on ships.
Li Quan belongs to the kind of activist who will do whatever comes to his mind. He actually assigned tasks on the spot: "In this way, I teamed up with Brother Ang Qi (Tian Yang) to calculate and produce a more precise lunar distance table. Master Sun and Yuan
Brother Jing (Wang Su) and his team invented and made the sextant. With the combination of the lunar elongation table and the sextant, ocean exploration will definitely be successful!"
"Okay, I'll do it with you." Sun Yunqiu smiled.
Zhao Han and Li Zicheng did not go hunting, but rode horses in the racecourse.
When he came back now, Zhao Han smiled and asked, "What are you talking about?"
Everyone stood up and saluted.
Feng Qizhi took the lead and said: "Reporting to Your Majesty, students and colleagues from the Hanlin Academy are discussing the doubts about oracle bone inscriptions. I deeply feel that our knowledge is insufficient and we need to be more diligent."
Zhao Han looked at the ground in front of them and saw several oracle bone inscriptions, as well as bronze inscriptions, seal inscriptions and other changes. He immediately nodded in approval: "Not bad, keep up the good work."
"Thank you for your encouragement, Your Majesty!"
The four young people from the Hanlin Academy bowed and saluted with excitement.
Zhao Han asked Qintianyuan again: "Where are you?"
Li Quan replied: "Reporting to your Majesty, the students are discussing navigation matters. It has been agreed that the students and Tian Yang will improve the lunar distance table, and Master Sun and Wang Su will make a sextant. As long as these two are done well, we will be in the vast ocean.
The longitude and latitude of the sea can also be measured quickly."
"Sextant?" Zhao Han smiled and nodded, "Very good, Dashan!"
Li Quan suddenly knelt down and said: "Your Majesty, the student has a heartfelt request."
Zhao Han said: "Let's talk."
Li Quan said: "I learned about the stories of Magellan and other navigators from Western scholars at Qintianyuan. We have great unity in China, but there are still no navigators, let alone sailing around the world. How could the Huanghuang Dynasty lag behind the Western barbarians?
?Your Majesty, please give me five ships, equipped with experienced captains, star pilots, sailors and soldiers. I want to start from Shandong, cross the ocean eastward, and explore America for my kingdom first!"
At this time, the starting point of the Pacific route in Asia was the Balintang Strait, between Taiwan and Luzon. Even hundreds of years later, it was the most important waterway to Japan.
In view of the development level of Nanyang in the 17th century, the best starting point for the Pacific route should be in northern Taiwan.
Therefore, Spain would colonize Keelung in the first place. As long as Keelung Port is developed and Chinese goods can be obtained nearby and shipped directly to the American colonies, Spain can even abandon Manila by that time.
However, the Spaniards think too simply and do too many tricks.
First, the Han people were not allowed to help develop Keelung, so the port and city never prospered, and the food Keelung needed had to be shipped from Manila. Second, due to the lack of Spanish troops, the Taiwanese natives bullied them miserably, and even the castle
All were breached at one time.
In desperation, Spain had no choice but to abandon the colony of Keelung.
Spain's current Pacific route starts from the South Philippine Islands, passes through Manila and goes to the Balintang Strait. Then it goes along the Ryukyu Islands, from the southern waters of Japan to the east, and follows the ocean current to the Americas. In the Americas, it follows the ocean current and returns in a straight line.
Balintang Strait, and then southward through Manila to the Southern Philippine Islands.
Luzon, Taiwan, and the Ryukyu Islands have all been controlled by China. The Balintang Strait has almost become China's internal sea, directly cutting off the Asian starting point of the Pacific route.
In such a situation, Spain would not dare to have a conflict with China. If a war did break out, the Chinese navy would not need to do anything else but block the Balintang Strait, and Spain's galleon trade would be declared over.
Li Quan's idea was to start from Shandong, use Japan as a springboard to go to America, and open up a "Shandong-America" route.
This route is of little use now, but if Chinese maritime merchants want to do business in the Americas in the future, they will have two routes to choose from: one is Taipei-America, and the other is Shandong-America.
Zhao Han showed a pleased expression and asked: "Walking thousands of miles across the sea, narrowly escape death, do you know the dangers involved?"
Li Quan answered categorically: "Even though I died nine times, I have no regrets!"
This man definitely couldn't be a consort, Zhao Han didn't want his daughter to be a widow in ignorance.
(Thanks to Magic Cultivation Essentials, enter the nickname of the leader who already has the reward, thank you two brothers.)