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Astronomical telescopes or astronomical binoculars are the optical instruments used to help the eye see celestial objects such as stars, planets, satellites, etc. Although the size of celestial objects is huge, the distance of celestial objects is so far that when observed using the eyes, celestial bodies appear small. Astronomical telescopes function to enlarge the image of celestial objects so that they can be seen using the eyes.
Article about the Equation of microscope
Angle determines the size of the image of the object formed on the retina of the eye. As shown in the figure on the side, the smaller the size of the object, the lower the angle and hence the lower the size of the image formed on the retina. The small size of the image on the retina is the reason the eye is difficult to see small objects clearly, even though objects are viewed from a near point, a distance of 25 cm.
A microscope is an optical instrument used to help the eye see minimal objects, where the tiny objects are difficult to observe directly using eyes or loupe.
There are two types of the microscopes, namely light microscope and electron microscope. This lesson discusses the light microscope, and the way it works about the topic of geometry optics includes refraction of light, the formation of images and the magnification of images of an object using a lens.
As explained in the topic loupe (magnifying glass), an object appears small when viewed from a great distance and looks great when viewed at close range. The difference in the size of the object seen by the eye is caused by the difference in angle between the eye and the object. When an object is very far away from the eye, the angle between the eye and the object is smaller so that the image formed on the retina of the eye is also smaller. Conversely, when the object is close to the eye, the angle between the eye and the object is larger so that the image formed on the retina of the eye is also more significant. The closer to the eye, the higher the angle between the eye and the object, so that the image that forms on the retina is also getting bigger. Kindly note that the average human eye has a near point is 25 cm so that the distance between the eye and the object cannot be smaller than 25 cm. It can be concluded that the angle between the normal eye of an average human and an object is maximum when the distance between the eye and the object is 25 cm.
A loupe or magnifying glass is a convex lens that is used to help the eye see an object that is difficult to observe directly using the eye. The loupe is called a simple magnifier because it has limited ability to magnifying the image of an object. In the next lesson, you will learn about non-simple magnifiers such as microscopes, etc.
Nearsightedness eyes can be normalized using eyeglass lenses and contact lenses. Eyeglass lenses are affixed to the eyeglass, while contact lenses are attached to the eyeball. Eyeglass has a certain distance from the eye, while contact lenses stick to the eye so that the distance between the contact lens and the eye can be ignored.
An example of problems experienced by a person with nearsightedness and farsightedness is explained, what types of lenses are used to normalize the eyes, what is the focal length and power of the lens. This focuses on the use of contact lenses in normalizing nearsightedness and farsightedness.
Nearsightedness can be normalized using eyeglass lenses and contact lenses. Eyeglass lenses are affixed to the eyeglass, while contact lenses are attached to the eyeball. Eyeglass has a certain distance from the eye while the contact lenses stick to the eye so that the distance between the contact lens and the eye can be ignored.
In this paper, we explain examples of problems experienced by sufferers of nearsightedness and farsightedness, the type of lens used to normalize the eye, and the focal length and the power of the lens. This focuses on the use of glasses to normalize nearsightedness and farsightedness.
Definition of the nearsightedness eye
Nearsightedness or hyperopia is an optical eye abnormality in which the eye cannot see the near point or the near point looks blurred. The average normal-eyed human has a near point of 25 cm.
The cause of the nearsightedness eye
Based on the previous explanation, it can be concluded that the cause of farsightedness is the cornea and the lens of the eye is less curved,
so that the focal length of the cornea-eye lens system is more significant, causing the beam of light from the near point to be focused behind the retina.
Definition of the farsighted eye
Nearsightedness or hyperopia is an optical eye abnormality in which the eye cannot see a near point clearly, or the near point looks blurred. Although it is difficult to observe a near point, people with nearsightedness can see the far point. The near point is the closest distance that can be seen by the normal eye. The average normal-eye has a point near 25 cm. The far point is the farthest distance that can be seen by normal eyes. The average normal-eye person has an infinite point. Infinite is a term used to describe the length of a very distant object.
Article Optical instrument human eye
Parts of the eye
The cornea is a transparent, hard membrane covering the front of the eye. The cornea refracts the beam of light entering the eye.
The pupil is black parts of the eye. The pupil is black, therefore absorb almost all the light. A pupil is a hole through which light passes into the eye. The larger the diameter of the pupil, the more light enters the eye and the smaller the size of the pupil, the less light comes to the eye.
The iris controls the size of the pupil. When the environment around the eye is very bright, the iris minimizes the pupil. Conversely, when the environment around the eyes is less bright, the iris enlarges the pupil so that the amount of light entering the eye is large. If you have observed the difference between the cat’s eye during the day and night, then you can easily understand the function of the iris.
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