Brief introduction of astronomical telescope

Lead: According to the different structures, optical astronomical telescopes can be roughly divided into three categories: refractive telescopes with lenses as objective lenses; Using a mirror as the objective lens is called reflecting telescope; It contains a lens and a mirror, which is called a catadioptric reflecting telescope. Refractive astronomical telescope is widely used and convenient to use, which is more suitable for astronomical popularization. In addition, there are radio telescopes and space telescopes used for scientific research.

Introduction to the performance of astronomical telescope

1, magnification

Looking at the scenery on the ground or on the moon through an astronomical telescope, it seems that objects have become very close. At the same time, many potholes can be seen on the surface of the moon. This is because the telescope has a magnifying function.

How is the magnification of the telescope calculated? Magnification is the focal length of the objective divided by the focal length of the eyepiece.

In the calculation of magnification, the focal length of the objective lens is usually fixed. By changing different eyepieces, we can observe the stars and seasons with many different magnifications. The larger the magnification, the smaller the visual range.

2. Light-gathering ability

Another important performance of a telescope is its ability to concentrate light. Concentrating light is the ability of a telescope to collect light. The concentrating power is determined by the aperture of astronomical telescope. The bigger the mouth, the stronger the light gathering ability, and the darker the stars you can see.

3. Analytical ability

Resolution is the ability to distinguish whether an object is clear or not, which is related to the aperture size. The larger the aperture of the telescope, the better the resolution.

4. Extreme magnitude

The larger the magnitude, the darker the star. There is a limit to how dark the stars can be seen by astronomical telescopes, so every astronomical telescope has a limit magnitude. For example, a telescope can only observe stars such as 13, but cannot observe stars such as 15.

5. objective lens

The larger the diameter of the objective lens, the darker the magnitude that can be seen. Small aperture objective lens is suitable for observing planets, and different stars need astronomical telescopes with different apertures.

Structural main lens barrel of astronomical telescope

The main lens barrel is the protagonist who observes the starry sky. With different eyepieces, we can look at the stars at will.

Star detector

The main lens barrel usually observes the stars at a magnification of several tens times or even higher. When looking for stars, if it takes dozens of times to find them, it is not so simple for Shanghai Observatory to find stars with the main lens barrel. Because the field of view is small, we use a small telescope with only a few times magnification, and use its function of large field of view to find out the position of the star to be observed first, so that we can directly observe the stars with low magnification in the main lens barrel.

eyepiece

If an astronomical telescope lacks an eyepiece, there is no way to see the stars. The function of the eyepiece is to enlarge. Usually a telescope should be equipped with three kinds of eyepieces: low, medium and high power glasses.

equatorial telescope

The equatorial telescope is a device that can track stars and observe them for a long time. There are many forms of declination instruments. We often see declination instruments in Germany, which are divided into declination axis and declination axis, among which declination axis is the most important. When in use, the axis of the right ascension axis should first be aligned with the north pole of the celestial sphere. After finding the star, start the tracking motor and lock the clutch to track the star. In order to align the right ascension axis with the north star, the Beijing Planetarium installed a small telescope in the center of the right ascension axis, called the polar axis telescope. On the right ascension axis and the right declination axis, there are big and small fine adjustments, and their function is to help find the stars.

Tracking motor

Right ascension tracking motor can drive the right ascension axis to rotate reversely at the same angular velocity as the earth's rotation, tracking the stars and keeping the stars in sight for a long time. In addition, we can find the stars to be observed at a faster speed, and increase or decrease the weather in Shanghai to do the function of astrophotography. The function of declination tracking motor is to adjust and correct the observed stars when they deviate from the center of the field of view, and to find the stars and astrophotography. Magnetic declination meters generally need magnetic declination motors. If astronomical images need to be photographed for a long time, both magnetic declination motors and magnetic declination motors are needed.

Tripod table and tripod

The tripod table is use for receiving a tripod connecte with that equatorial telescope and the lens barrel, and the tripod is used for bearing the telescope and the equatorial telescope and is use as a pillar. A tripod is generally used for small equatorial glaciation 3 instruments, and a single column foot is used for heavier equatorial glaciation instruments.

Control box and power supply of magnetic declination meter

In order to run the equatorial telescope, a power supply is needed to drive the tracking motor. Generally, portable red plum rain songs and musical instruments need to buy dry batteries or storage batteries, which are suitable for use in wild mountainous areas. The control box design of equatorial telescope has many functions to meet the needs of observing stars, searching for stars and engaging in celestial photography.