The aurora made everyone's vision better, and also accelerated the speed of the three fools.

The sled dog's endurance is excellent, if you run happily, you will be fine for most of the day, in view of the load and number problems, two hours later, Bi Fang pulled the three fools, stopped the sled, ready to rest.

"In two hours, we ran at least 25 kilometers, which is much faster than I could go."

The normal speed of human snow walking is only about three kilometers per hour, in other words, without the help of sled dogs, Bi Fang would have walked for at least a whole day, but all this was done by the three guys in front of him in just two hours.

"Of course, this is the energetic pace at the beginning, and then it's not so fast, maybe it's going to be halved, but it's still much faster than walking on my own, maybe we'll be to the coast tonight."

Bi Fang touched the panting dog's eggs, took out the dog basin, poured some water and food for the three fools respectively, and then did it himself, enjoying the wonderful night view, and chatting with the audience.

Half an hour later, after the break, Bi Fang moved forward again, and it was not until the third break that the audience raised questions, because they found that Bi Fang's rest time was too regular, that is, running for two hours and resting for half an hour.

If it's usual, it's okay, but how does Bi Fang judge the time?

"Ah, this one, it's actually very simple." Bi Fang pointed to the sky.

Although there is no watch and no sun, Bi Fang still has many ways to judge the time, and it will not affect his actions because of the time, such as looking at the moon in the sky, or directly asking the audience in the live broadcast room.

Ahem, of course, the last one is suspected of cheating, unless it is an emergency, usually Bi Fang will still choose to judge in his own way.

"In the wilderness, judging time is usually not that important, because a lot of times you don't really need it."

Survival in the wild is no better than in the city, and there is no one who dictates what you have to do according to when, everything is up to you.

If you want to survive, all you need is food, water and fire.

The acquisition of the three is only a little related to the time when hunting food, but this relationship is not very much, as long as you avoid the time when predators are most frequent at dusk and night.

Bi Fang has never encountered the polar night phenomenon before, and it is based on the sunrise and sunset, but now due to the dog sled, it is necessary to decide the regular rest through time to improve efficiency.

"That's exactly what happened, so I never talked about how to tell the time, in fact, this is also very simple."

"The sun, the moon, and the stars rise in the east and set in the west, running endlessly. The rise and fall of celestial bodies is like a natural clock that shows the hour. In astronomy, using this natural phenomenon, it is possible to determine the exact time by observing the stars with precision instruments. ”

"But we can look at the stars in an easy way, and we can also set an approximate time. Although the exact procedures are different, the basic principles remain the same. Although not usually used in the wilderness, it is still useful for night walkers. ”

[Uh, the stars can also tell the time? 】

[I can understand the sun, even if it's the moon, but the stars are a bit exaggerated]

[I always thought that the stars could only be used to judge the direction, Lao Fang, are you confused, frozen and confused]

[It turns out that all those who doubt the old party have been slapped in the face in the end, so honestly take out your notebook and start studying! ] 】

Some people expressed doubts about Bi Fang's statement, the sun and the moon, the former is easy to judge the time, the latter is not impossible, but it is more difficult, but the stars are outrageous!

[Anyway, why is there no moon today, isn't it sunny?] 】

Speaking of the moon, many viewers suddenly noticed that it was a starry sunny day, but there was no moon in the sky?

"Of course not, when the 'Arctic Night' arrives. It is only for half a month that we can see the moon, round or absent, revolving around the sky all day. The other half a month is not even visible to the moon, obviously, now is the half month when the moon is not visible, otherwise I would not use the stars to judge the time. ”

[Talk, I want to learn]

Bi Fang freed up a hand and pointed to the sky: "Do you see the Big Dipper above?" ”

In the first person, the audience easily found the Big Dipper that Bi Fang was referring to, and responded again and again.

"As I said before, we face north, and then we take the two pole stars at the mouth of the Big Dipper, and imagine that they are more than five times longer, and we can find the North Star."

"Now we think of the North Star as the center of the watch surface, and the line that points to the Pole Star and the North Star as the hour hand. It is divided into twelve equal parts on the clock face: 12 on the top, 3 on the right, 6 on the bottom, and 9 on the left, and this is the Big Dipper clock. ”

Because the person's eyes are the same, what Bi Fang sees and refers to is completely consistent, so there is no misreading, and under the hand-in-hand identification, the audience can easily imagine a big clock.

[Big Dipper Star Clock, this name is so cool]

"Since the stars rise in the east and set in the west, the hour hand of the Big Dipper turns in the opposite direction to the hour hand of an ordinary clock. After 12 o'clock, it refers to 11 o'clock, then 10, 9, 8, 7...... Although the hour hand of a star clock rotates in a different direction than an ordinary clock, it is possible to get the same time as a regular clock. ”

"When observing, as long as you remember the local longitude, remember, here to express the longitude in units of time, because the earth rotates 360 degrees, it takes 24 hours, so you can use 15 to divide the local longitude degrees to find, recognize the 'hour' number pointed to by the star clock hand, as well as the month and day of observation, and finally use a constant to subtract and subtract, and the required time is immediately obtained."

"This method can be written down in a simple formula, that is, capital time = 36.4 - longitude - 2 (hour number + m)."

"m is the number of months from January 1 to the observation time. If you get a negative number, add 24 hours. As for the source of the number 36.4 hours, it can be simply understood as a constant in the formula, and there is no need to understand it. ”

[I don't know how to feel it, I don't know how to feel it]

[Understood, but didn't understand]

[What I understand is that Fang Shen is awesome, the difference is how to judge the time (dog head)]

"It's actually quite simple." Bi Fang said with a smile, "For example, on the evening of June 1 of a certain year, at the Capital Planetarium, when the longitude = 7:45, you saw that the hands of the Big Dipper were at 10, and what time was the current capital time?" ”

As a result, Bi Fang waited for a while, and only saw that he had an answer after chatting with a few, so he didn't sell it, and came out directly with branches on the snow.

"This kind of thing, in fact, you can do mental arithmetic, and now you know that June 1 is 5 months apart from January 1, so M is 5. At this time, the capital time is ......"

A simple pose appeared on the snow, which made the audience suddenly realize.

36.4 hours - 7.8 hours - 2 (10 + 5) hours = -1.4 hours.

-1.4+24=22.6 hours.

That's 10:36 p.m.

"Sometimes we can't see the Big Dipper, but when the constellation of Cassiopeia rises almost opposite it, we can also use it, and the connection between the β star and the North Star in Cassiopeia can also be used as a 'hour hand'. The division of the clock face and the direction of rotation of the clock are the same as those of the Big Dipper clock. ”

"When calculating, you have to replace the constant of 36.4 with 25.5."

"Of course, if you have a 'stellar indicator disk', then you can almost not calculate, just pull the astrolabe, and you will know the time immediately, this is more complicated, if you have time, you can make one when you return to the wooden house."

"How's that, easy?"

Bi Fang clapped his hands and said happily.

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