Thirty years ago today, on July 23, 1995 (June 26, 1995), the end-of-the-century comet "Hale-Bopp" was discovered. Hale-Bopp's comet contrasts with the Northern Lights (April 1, 1997) On July 23, 1995, two amateur astronomers in the United States, Hale and Bopp, were observing the Sagittarius globular cluster M70 when they accidentally discovered a new comet. The calculation results of the preliminary observation data shocked astronomers: it turned out to be in a very special orbit, its orbit plane is almost perpendicular to the plane of the solar system, that is, it will go from south to north around the sun and then fly to the depths of space, so this comet will provide us with the physical state of the sun's poles and the edge of the solar system. What is more striking is its unusual brightness. When it was found, it was 1 billion kilometers away from the earth, and its brightness was already 10 degrees, 250 times brighter than Halley's Comet at the same distance when it returned in 1985. Later, astronomers calculated that when the comet passes perihelion, its brightness will reach -1.7 degrees, that is, brighter than Sirius, the brightest star in the sky, so it is called the end of the century comet. The comet Hale-Bopp lived up to expectations, and its morphological development and brightness were basically in line with estimates: the comet nucleus experienced at least five outbursts and had a short, thick dust tail. The gas tail appeared from January to February 1997, and it was longer at the beginning, and maintained two main tails, which remained the same until April. It passed perigee on March 23, 1997, and perihelion on April 1, reaching a magnitude of -0.8 at its brightest. "Hale-Bopp" is the first comet in human history to fully use CCD (electronic scanning system to record images) technology for long-term observations, and the quality of the photos has been greatly improved as a result. On March 4, 1996, the Hale-Bopp comet (locally enlarged) was photographed by a one-meter mirror with an enlarged field of view CCD device at the Yunnan Observatory in our country.