How can a concave mirror and a convex mirror form a simple telescope?

The two mirrors have different functions, one concentrating and one astigmatism, one zooming in and the other zooming out, so that the image of the panorama is reduced to the telescope, and people can see the distance clearly.

Because the telescope is to magnify the distant scene through the concave and convex mirror, and the near scene is reduced, and the concave mirror plays the role of shrinking, and the convex mirror plays the role of magnification, so a concave mirror and a convex mirror can form a simple telescope.

Whether a telescope is composed of a convex lens or a concave lens depends on the situation.

A refracting telescope is made up of two convex lenses; The objective lens of the reflecting telescope is a concave lens, and the eyepiece is a convex lens; Catadioptric is made up of two convex lenses and two concave mirrors.

A telescope is an optical instrument that uses lenses or mirrors and other optical devices to observe distant objects. Light rays that are refracted through a lens or reflected by a concave mirror allow them to enter a small hole and converge for imagery, and then pass through a magnifying eyepiece to be seen.

The first purpose of a telescope is to magnify the opening angles of distant objects, so that the human eye can see details with smaller angular distances. The second function of the telescope is to feed the beam of light collected by the objective lens that is much thicker than the diameter of the pupil (up to 8 mm) into the human eye, allowing the observer to see faint objects that were previously invisible.

Categories: Education Science >> Admission >> High School Entrance Examination Question Description:

Can you make a telescope with a concave lens and a convex lens? Which lens is the eyepiece and how does it work optically!

Analysis: Yes.

Homemade telescopes with two configurations.

One is the Kepler structure: it is two magnifying glasses, the objective lens is small magnification, and the eyepiece is large magnification. This structure has a wide field of view, the multiples are easy to size, and the materials are easy to find. But if you don't have a prism, then it's like it's upside down.

The other is the Galilean structure: a magnifying glass, with a small multiple, is the objective. A concave lens, with a large power, is an eyepiece. The advantages are like positive. Disadvantages – The advantages of the above methods correspond to each other.

The Galileo structure is actually obsolete for now, and is only used on toy telescopes, and the material is not particularly easy to find (there are many more convex lenses than concave lenses in life, right?). So if you're just looking at astronomy, you're going to make an astronomical telescope (you don't care about inverted images), then you can make a Kepler structure.

The important thing you need to know is that the flatter the objective lens and the more concave (or convex) the eyepiece, the greater the magnification of the telescope. However, it is not recommended to be very large.

Of course, the two I am talking about are just the simplest models, the real regular telescope, or more complicated in fact, not only the material is optical glass, but also the lens is also very complex From the introduction to the production of your professional telescope, you may already know - the so-called "convex lens" in it - in fact, the real production, with a complex design of the lens group - as if you know that the lens of the camera is a convex lens - the real professional camera lens, inside is a complex lens group. ）

Finally, just experience the fun of hands-on, don't spend too much energy, you can play by yourself, experience the fun of hands-on, but don't expect too much from the effect.

The principle of the optical telescope is to magnify the angle of view, that is, to make the object with a smaller angle in the line of sight, after optical refraction, the angle of view becomes larger, so that the object is larger in the eyes of people, and it seems to be closer to the person, plus its aperture is large, and the light captured is more, so that people can see more details, but also make people see clearly.

When the ordinary convex lens is used as a telescope, it is generally composed of two pieces, namely the eyepiece and the objective lens, of which the focal length of the objective lens at the front end should be as long as possible and the aperture is large, and the focal length of the objective lens at the back should be short, so that the imaging multiplier will be high and clear. The eyepiece can be adjusted from front to back so that you can see images at different distances.

What is the principle of myopia glasses?

Incorrect. The telescope introduced in the textbook is only one type of telescope, which uses two sets of convex lenses. And the objective lens is a convex lens. Whereas, large astronomical telescopes are usually reflective, and the objective lens is made of concave mirrors.

An objective lens is a lens group that combines several lenses. The purpose of the combination is to overcome the imaging defects of individual lenses and improve the optical quality of the objective lenses.

The magnification of the microscope mainly depends on the objective lens, the quality of the objective lens directly affects the quality of the microscope image, it is the main component that determines the resolution of the microscope and the clarity of the imaging, so the calibration of the objective lens is very important.

1.The objective lens of a refracting telescope is a convex lens. There are two types, one is the Galilean telescope: the objective is a converging lens (convex lens) and the eyepiece is a divergent lens (concave lens). The second is that the Kepler telescope consists of two convex lenses.

2.A reflecting telescope is a telescope that uses a concave mirror and a crop mirror.

Not necessarily, for example, Newtonian reflecting astronomical telescopes are composed of convex and concave lenses, and the objective lenses of the early Galilean astronomical telescopes were also made of concave lenses.

This is the case with ordinary optical telescopes, but not necessarily with large astronomical telescopes.

Both the microscope eyepiece and the objective lens are convex lenses. The microscope consists of two convex lenses (converging lenses), and the optical path diagram is shown in the figure below. The object AB is magnified into an inverted real image A1B1 through the objective lens, A1B1 is located on the inside of the object focal length of the eyepiece, and after passing through the eyepiece, it becomes a magnified virtual image A2B2 at the photopic distance.

The picture above shows the optical path diagram of the Kepler telescope. Parallel rays of light from celestial bodies, after passing through the objective lens, form an inverted scale-out image a b at a very close distance from the focal point. The front focus of the eyepiece and the focus of the objective lens coincide, so the real image A B is located very close to the focal point between the eyepiece and its focal point, and the eyepiece forms an enlarged virtual image ab with A b as the object.

When we look into the eyepiece, the light entering the eye seems to be coming from AB. Obviously, the angle of view of AB in the diagram is much larger than the perspective of viewing the object directly with the eye, so the object seen through the telescope makes the person feel closer to him and see more clearly.

The figure below shows the optical path diagram of the Galilean telescope's principle. The convex lens, which is the eyepiece, is changed to a concave lens, so that the human eye receives an upright virtual image. The Galilean telescope is an ancient telescope for viewing drama.

The eyepieces of telescopes have convex lenses as well as concave lenses.

The eyepieces of astronomical telescopes and Kepler telescopes are convex lenses. Whereas, the eyepiece of the Galilean telescope is a concave lens.

Working principle: Whether it is a convex lens or a concave lens, the eyepiece is to magnify the inverted and reduced real image of the objective lens into an upright virtual image. The eyepiece acts as a magnifying glass. The objective lens produces a solid image that is within the focal point of the eyepiece.

Basics: The objective lens collects the incident light, concentrates it to a point near the bottom, and then magnifies the image by the eyepiece.

Kepler: convex lens objective lens + convex lens eyepiece, inverted image, the angle of view is larger than that of Galileo, and it is most modern refractive telescopes.

Parallel rays of light from celestial bodies, after passing through the objective lens, are inverted and zoomed out of the focal point very close to the focal point. The front focus of the eyepiece and the focus of the objective lens coincide, so the real image is located very close to the focal point between the eyepiece and its focal point, and the eyepiece is inverted to reduce the real image to form a magnified virtual image. When we look into the eyepiece, the light entering the eye seems to come from a virtual image.

Obviously, the perspective of a virtual image is much greater than the perspective from which a celestial object can be viewed directly with the eyes, so a celestial object seen through a telescope makes a person feel closer to himself and see more clearly.

Galilean type: convex lens + concave lens eyepiece, upright image.

The eyepiece is a concave lens, which allows the human eye to receive an upright virtual image. The Galileo telescope is an ancient telescope for viewing dramas, which can directly establish a positive image, but the field of view is small, and now it is generally used in toy telescopes, as well as beautiful telescopes for viewing dramas, high-powered monoculars, etc., which are more inclined to be telescope products as craft gifts.

I hope the landlord can read it carefully.

Two convex lenses are required. One as an eyepiece and one as an objective. Objective focal length (how do I determine the focal length?)

Place the mirror in the sun, adjust the position, find a minimum and brightest point below, and measure the distance from the point to the center of the lens, that is, the focal length) should be large, and the aperture should be large enough, the focal length of 60cm and the aperture should be 40cm (because you are using ordinary glass, not special glass, in order to get enough light, so the aperture should be large).

Okay, the objective lens is over for now, and now let's talk about the eyepiece.

The focal length of the eyepiece should also be large (using the principle of magnifying glass), but it should not be too large, it should be smaller than the focal length of the objective, about 20cm (the smaller the magnification, the stronger the magnification, pay attention to the focal length should not be too small). A diameter of 5cm is sufficient.

The most important thing is the position relationship between the objective and eyepiece. Objective imaging uses the camera principle of a convex lens, and the image of the object is between the double focal length and the double focal length, and the image is inverted and reduced. The eyepiece is then placed between one and twice the focal length of the objective, i.e. between 140 and 180 cm.

When you're done, center the objective and eyepiece in the same position, and then select the appropriate material to assemble.