Chapter 19 V variable star

Ancient Chinese astronomers emphasized the observation of the positions of stars, but did not pay attention to the quantification of the brightness of stars. Some descriptions, such as bright, bright, and small, have vague concepts, and their understanding varies from person to person.Only variable stars, and those that vary in brightness between the visible and the invisible, are noted by astronomers and recorded. "Historical Records Tianguan Shu" records: "There is a saying that the fifteen stars of the circle [huanhuan] belong to the dipper, which is called the prison of the bitch. The stars in the prison are actually many prisoners, and the empty ones are released." The last two sentences are very important, meaning That is, if the "prison" is full of stars, there will be more prisoners, and if the "prison" is sparse, the prisoners will be pardoned.Sometimes there are many stars, sometimes there are few stars, which means that the brightness of some stars is changing.When they become stars of the sixth magnitude or above, they will be seen by people, otherwise, they seem to disappear.The slut's prison mentioned by Sima Qian is the later Qigong Xingguan and Guansuo Xingguan. Compared with the modern star map, this part of the sky is equivalent to the Northern Corona.There are indeed three variable stars in Coronae Borealis, α Coronas Borealis, T Coronas Borealis and R Coronas Borealis, and the brightness fluctuations are 2m-9.m5, 5.m8-12.m5 and 6.m1-12m respectively, all of which change Between the visible and the invisible, the observations of the ancients are confirmed to be correct.

There are still many astrological texts about the changes in the brightness of stars, which will become rare research materials after eliminating the false and preserving the true.