Chapter 446: Set off again

In addition to observing the starry sky, it is also necessary to observe the sun, observing its angle of incidence to the local area at different times.

After ten years of continuous exploration and improvement, Su You ironically found that with glass lenses and a brass instrument panel with precise angles, the theodolite was transformed by Taoist priests to be closer and closer to the sextant of later generations, and even the black shading glass was installed, and it was divided into different layers to resist different periods of sunlight of different intensities.

No one is stupid! This is almost indistinguishable from the sextant of later generations!

As soon as the national statistics were summarized, Si Tianjian and Yujuguan found that at the same point in time and different positions, the angle of incidence of the sun was different! There is a difference between the time calculated according to the catalog and the time calculated according to the solar measurement!

For the lives of the people, this thing actually has no impact, just the sunrise and the daily income and rest.

But this is a very serious problem!

First of all, there is a question of legitimacy, where time is the standard?

This matter also attracted the gods and demons of all roads to tear up, from Yugong Kyushu, the world to the sunrise Fusang, and finally the boss of the Tianjian solemnly said, Your Majesty, the position of the Zichen Hall of the Bianjing Palace must be the only standard time observation point in the world!

Zhao Shu was stupid when he heard it, Aiqing, you are very reasonable, there is only one question, are you going to climb above my head to observe?

Fortunately, an important application method of science and technology is to be flexible, Si Tianjian replied: "This question is very professional, but after our observation, we have found that this time has a relatively large relationship with the east-west position of the region, and a small relationship with the north-south relation, so we can set up an observation point in the direction of due south and due north of the throne, and accurate measurement is enough." ”

Zhao Shu breathed a sigh of relief, it was so dangerous, but fortunately there was a perfect solution.

A few years later, the astronomical calendar with this point as the origin was made, and the Taoist priests made a new discovery, that is, the lines connected at the same point in time could not divide the earth on the map according to the normal straight!

One question after another, the people of Si Tianjian were about to cry.

Who can fix it? All thought of one person.

It's not Su You, it's Su You's brother, Su Song.

Su Song studied the map and the meridians on it, and came up with an idea.

"Huainan Zilan Spiritual Training": "In ancient times, the four poles were wasted, and Kyushu was divided; The sky is not covered, and the earth is not circumferential. So the female calamity refined the five-color stone to make up for the sky, and the broken ao was enough to set up the four poles. ”

Could it be that the earth is not completely flat? But it's like a back? So that the sun shines up, will there be such an effect?

My one goes! Su Zhihe is really powerful! This is the only explanation!

After such a pleasant decision, the Kyushu warp was introduced.

In ancient China, there has always been a theory of division, after the theodolite was used smoothly, the Taoist priests converted the geographical division corresponding to the stars into the scale division of the theodolite, so that the measurement is more accurate.

This also requires the measurement of latitude.

Latitude measurements are relatively simple, as there is a North Star in the Northern Hemisphere that astronomers have been using to locate the star Polaris.

The altitude angle of the North Star is the latitude.

As a result, under the guidance of all kinds of ghosts and gods, the longitude and latitude of the celestial sphere that had existed for a long time became the longitude and latitude on the ground.

As for the hourglass, the length of the day is measured, and then divided into 24 parts, so that the sand in the hourglass can be drained for exactly half an hour at a time.

The hourglass is glass, so you can easily see the sand leaking inside.

It is still fine and pure, and the time of each day of the sun is different, which is called the true solar day.

Therefore, it is necessary to take an annual average, which is called a mean solar day.

Zhang San understood the trigonometric relationship of mathematics and light refraction, but when Su You put this pile of things in front of him, he was still a little confused.

Little Brother Qi used to look at the moon with a peep mirror, but he caused a lot of trouble.

Su You patiently drew a picture and explained, the sextant is only easy to use on the sea, and there is really no way to play conveniently in Meishan.

Because of this thing, the horizon is needed.

However, the principle can be drawn, and it is not complicated at all, it is an angle ruler, and on one side is a horizon mirror, an indicator mirror, and a telescope.

When the indicator arm coincides with the zero degree of the angle ruler, the horizon mirror is parallel to the indicator mirror.

The observer observes the sea level with a telescope, and the gaze looks through the horizon mirror, which is half transparent and half mirror, and at this time, there is no sun in the mirror.

The telescope does not move, rotates the angle ruler, and the angle ruler drives the indicator mirror to adjust the angle, and gradually, the sun is reflected through the indicator mirror, appears on the horizon mirror, and finally tangential to the sea level.

Write down the angle readings on the sextant scale at this time, and through a series of calculations, you can get the angle of incidence of the sun.

The angle of incidence of the sun at noon is different at different latitudes, and this can be checked through the astronomical calendar, even if it is not within the statistical range of the Kyushu astronomical calendar, you can calculate the exact latitude of the location.

The calculation of longitude can be carried out by time difference.

Through the ephemeris, you can observe the standard time of Bianjing at night, then record this time with an hourglass, and then measure the sun at noon at the location of the ship during the day, you can get the time difference between the measurement point and Bianjing, and then calculate the longitude.

For Zhang San, this is a set of life-saving magic weapons.

There is nothing more important than knowing where the nearest port is and which direction to go on on the vast sea.

In addition, in the past, you could only sail along the coastline to find a land mark, but now you can adjust to take a shortcut.

What does the Meishan proverb say? Time is money, efficiency is life!

Of course, these are only feasible in principle, and through repeated measurements, experiments, and the combination of experience, a set of effective methods can finally be formed.

This task fell on Zhang San, compared with shipbuilding, this is the core technology that the Qian family can't master for a while.

Every time I go to sea in the future, I will gradually improve the nautical charts and route maps, and with the giant high-speed schooners and nautical surveys, the sea will no longer be a daunting path.

As for the human threat, even in a few hundred years, no nation's sea-going ships could be the enemy of armed schooners armed with ballistas.

In June, the renovation of the new sailboat was completed, and Su You began his tour in his own jurisdiction.

When people are old, they don't want to move their nests, Bagong has never been out of Kelongli in his life, Su You wants him to go to Bianjing to enjoy happiness, that is a luxury.

What's more, in Bianjing, it is not necessarily better than enjoying happiness in Meishan.

In the eyes of Hachiko, apart from being crowded and close to the official's house, what is better than Meishan?!

Even if he was reluctant, Su You could only wave goodbye to the eight princes and his party who saw them off, and many people, after this time, didn't know if they could see each other again.

Kind of math has improved by leaps and bounds, because interest is the best teacher.

The elite of the 6,000 Xia Army in Shuiluochuan was wiped out like butter by a knife with the help of grenades; A fire and explosion outside the city of Weizhou plunged the 70,000-strong army into chaos and left the dragon leaderless. completely overturned this baby's understanding of war.

The decisive force of future wars must be firearms!

In order to use ballistas flexibly, knowledge of mathematics and physics is indispensable, and any good artillery commander in later generations must first be a scholar who is proficient in mathematics.

Su oil is indispensable, math problems, ten years, translation and memory, as well as practical applications in science and engineering engineering, all accumulated one by one, that is sweat cows.

In the future, there may not be too many opportunities for him to lead the army, and these boys grow up, and they are the real minions of the Great Song Dynasty.

Cao boat along the newly rising river all the way east, everywhere to go, Su You summoned Yi Han, preached the new policy of the imperial court, verified the warehousing, roads, bridges, taxes, and listened to the work reports of the officials.

As the spokesperson of the emerging commercial financial consortium, it is needless to promote the use of Shu banknotes, and with the elite team of firm accountants as the statistical and verification force, it is almost impossible for the officials to get through the accounts in confusion.

The benign growth of the economic situation in Shuzhong for more than ten years has covered up the flaws in the governance of many places.

This trip to Suyou is aimed at these flaws.