Visible light, as perceived by the human eye, is only a small part of the electromagnetic spectrum.  And those invisible light is everywhere around us, we just can’t see them.  For different bands of light or electromagnetic waves, need to use different telescopes to detect, used for astronomical observation telescopes collectively known as astronomical telescopes.  

Perhaps you also fantasize about observing the stars in the sky in the past. You are also curious about astronomy, so a pair of telescopes is essential. Learn this article, let us step into the world of telescopes.  

1. The principle of astronomical telescopes  

Telescopes detect electromagnetic waves.  Optical telescopes detect visible light, which is called seeing the stars themselves;  Radio telescopes detect radio waves, which are a type of radio wave, and radio waves have lower frequencies than visible light.  However, the specific detection methods are also different.  

Optical telescopes look at light from stars, but many of those stars are long gone, and we see light from billions of years ago.  An optical astronomical telescope is divided into reflection, reflection, and refraction reflection astronomical telescope.  As the name suggests, refracting telescopes use the imaging principle of a convex lens to see a real image;  The principle of the reflective telescope is to use the reflection of a plane mirror to see a virtual image;  A trans telescope combines the two and sees a virtual image.  

The radio telescope, it belongs to the astronomical telescope used by professional observatories, receives the radio waves from the stars, and then records the key data, including the intensity, spectrum, polarization, etc., at the same time, it is also equipped with professional information processing system to process the collected information.  Under such conditions, stars that cannot be observed with ordinary optical telescopes can be observed.  

2. Classification of astronomical telescopes  

An astronomical telescope consists of an objective lens and an eyepiece. The convex lens or concave reflector near the object is called an objective lens, and the one near the eye is called an eyepiece.  The astronomical telescope can be divided into refraction astronomical telescope, reflection astronomical telescope, refraction astronomical telescope, and radio astronomical telescope.  

When we talk about telescopes, we usually refer to optical telescopes, that is, telescopes that can be used to detect visible light, but they cannot be used to detect other wavelengths of electromagnetic waves.  In appearance, a refracting telescope looks more like what you might think of as a telescope, while a reflecting telescope looks like a big barrel.  In simple terms, refracting telescopes are better suited for observing objects in the solar system (moon, moon, earth), while reflecting telescopes are better suited for observing objects in deep space.  

3. Types and structures of astronomical telescopes  

An astronomical telescope consists of a primary mirror, a star finder, a zenith mirror, an eyepiece, an equatorial apparatus, and a tripod.  The primary tube is the main body of an astronomical telescope, and the objective lens and the tube are integrated.  The length of the lens tube determines the focal length of the telescope, and the diameter of the objective lens determines its diameter.  

Star finder is used to find objects because the telescope has a very small field of view, it is very difficult to find objects through the star finder, but the larger field of view, it is easier to find objects, similar to the “gun aim” of a sniper rifle.  After the mirror is calibrated, the target is positioned right in the middle of the mirror, and then the target can be seen through the telescope.  

A zenith mirror is an accessory of a refracting telescope for easier observation of celestial bodies near the zenith.  Because the objective lens of a refracting telescope is in line with the eyepiece, if we want to observe a planet near the zenith, the barrel will be up and the eyepiece will be down, making it extremely inconvenient for us to observe.  A zenith mirror uses a 90-degree prism to align the eyepiece with the barrel, making it easier to observe objects near the zenith.  

The eyepiece is mounted on the zenith mirror. The eyepiece and objective can be combined to see the distant stars. Moreover, the focal length of the eyepiece determines the multiple of the telescope, so each telescope usually comes with at least two eyepieces with different focal lengths.  

The equator can be used to overcome the effect of the earth’s rotation on stargazing, and it is also the base of a fixed astronomical telescope.  The equator allows the telescopic tube to be rotated up, down, left, and right so that the movement of the tube can be more accurately controlled during continuous observation of a certain celestial object.  There are several levels of the equator and the higher the level, the more accurate and carrying capacity it has.  

The tripod plays the role of supporting the astronomical telephoto. The multiple of the astronomical telescope is high. The stable tripod can avoid shaking and make the observation effect better.