Telescopes
History:
The credit for the invention of the first telescope has most sources pointing to Hans Lippershey, a Dutch optition (maker of spectacles). These were seen as a type of spyglass and consisted a convex objective lens and concave eyepiece. It focused by sliding simply into itself. These first telescopes were refracting telescopes. The first person to use the telescope for astronomical observations was Galileo Galilei. In 1609, the beginning of what would become the basis to observing the universe began. Galileo's first improved telescope design brought objects being viewed twenty times closer, with this he was able to view mountains and craters on the moon, plus a hazy silver line that was later named the Milky Way. These were also refracting telescopes, only larger. They also consisted of a tube with a glass lens and eyepiece at either end. As the quality of glass improved over the years, so did the images from the telescopes, but it wasn't until 1688 that the next renowned telescopic design was created. This was when the reflecting telescope came into use, which was invented by Sir Isaac Newton. With this new design, clearer images and closer magnification were available to view the stars, planets and other heavenly bodies. Nowadays, most professional observatories hold reflecting telescopes. In fact, the famous Hubble Telescope is a reflecting telescope. The Hubble telescope was a much awaited dream for astronomers for many years before it was actually initiated. The idea of having a telescope not held back by the haziness from the Earth's own atmosphere was intoxicating. Dreams were made real when in 1990 the Hubble telescope was placed approximately 600km above the Earth.
Refraction:
Refraction is the distortion of light making an image appear to the human eye as larger, in a different place, or have different qualities than its original form. It is the bending of light or sound waves. Refraction occurs when the light waves move through a medium to another medium which causes a change of speed, this is what creates visual illusions of an image.
A common example of refraction is when a straw is put into a cup of water. The end of the straw that is in the water appears to be larger and not able to fit onto its other end out of the water, giving the straw the appearance that it is broken. This is due to the light waves passing through the glass cup and further through the water, when it hits the straw the light causes distortion of the appearance of the straw.
Refracting telescopes consist of a convex objective lens at the end of a hollow tube to diffract or change the path of incoming light waves. This lens is used to collect more light than the human eye is capable of. It also has a smaller eyepiece at the other end for the light wave information to be received by us as a larger image than our naked eye can see. When light passes through the objective lens, it is refracted or bent. The light waves that enter this lens at a parallel, end up crossing over each other or meeting at a focal point. Light which enters at an angle, combines on the focal plane. It is a combination of both directions of light waves that give an image further refraction and magnification through the eyepiece (see below). The extend of the magnification itself depends on how large the telescope and lenses are. The larger the objective lens, the more light can be gathered. When the light has reached through the eyepiece, due to the converging of the light beams, the image may appear backwards or upside-down.
Reflection:
Reflection is described as the act of light rays hitting a surface and bouncing back into the same medium. This can occur on almost all surfaces with some able to reflect more light than others. The size of the angle that the light ray hits a surface is the same as the angle when it reflects off of it.
The most common and known instance of reflection is looking in a mirror. A mirror has the most reflective surface of all known surfaces on Earth. The image produced is an exact replica of what ever is being projected by the light waves. Symmetrical in every way. The distance that the object being reflected is from the mirror, is the same distance away in the reflected surface. This is caused from the light rays bouncing off of the surface of the mirror and back into the medium, sending the image directly to the eye.
A reflecting telescope involves the use of curved, angled and straight mirrors to transfer light from the entry point to the eyepiece while keeping a clear image of an object or objects. It uses these mirrors to gather light and return it along an optical point to the focus point (eyepiece). The amount of mirrors, depends on the size and quality of the telescope. A reasonable reflecting telescope will consist of a large concave mirror (primary mirror) at the opposite end of the point of light entry and an angled mirror in the central bottom end of which reflects the light through the eyepiece (see below). When light hits the primary mirror, it bounces back to a focus point called the focal plane. Due to the concave surface of the primary mirror, the light rays are angled and sent to the opposite angled mirror where they hit at a closer angle to that which they hit the primary mirror. This straight but angled mirror send the image up to the eyepiece which is then registered by the eye. Other, larger or more complicated reflecting telescopes may have the primary mirror, an angled mirror and a convex mirror, which would help gather and pinpoint the light. The point of focus in a reflecting telescope comes in when the angled mirror aims the light at the eyepiece.
The credit for the invention of the first telescope has most sources pointing to Hans Lippershey, a Dutch optition (maker of spectacles). These were seen as a type of spyglass and consisted a convex objective lens and concave eyepiece. It focused by sliding simply into itself. These first telescopes were refracting telescopes. The first person to use the telescope for astronomical observations was Galileo Galilei. In 1609, the beginning of what would become the basis to observing the universe began. Galileo's first improved telescope design brought objects being viewed twenty times closer, with this he was able to view mountains and craters on the moon, plus a hazy silver line that was later named the Milky Way. These were also refracting telescopes, only larger. They also consisted of a tube with a glass lens and eyepiece at either end. As the quality of glass improved over the years, so did the images from the telescopes, but it wasn't until 1688 that the next renowned telescopic design was created. This was when the reflecting telescope came into use, which was invented by Sir Isaac Newton. With this new design, clearer images and closer magnification were available to view the stars, planets and other heavenly bodies. Nowadays, most professional observatories hold reflecting telescopes. In fact, the famous Hubble Telescope is a reflecting telescope. The Hubble telescope was a much awaited dream for astronomers for many years before it was actually initiated. The idea of having a telescope not held back by the haziness from the Earth's own atmosphere was intoxicating. Dreams were made real when in 1990 the Hubble telescope was placed approximately 600km above the Earth.
Refraction:
Refraction is the distortion of light making an image appear to the human eye as larger, in a different place, or have different qualities than its original form. It is the bending of light or sound waves. Refraction occurs when the light waves move through a medium to another medium which causes a change of speed, this is what creates visual illusions of an image.
A common example of refraction is when a straw is put into a cup of water. The end of the straw that is in the water appears to be larger and not able to fit onto its other end out of the water, giving the straw the appearance that it is broken. This is due to the light waves passing through the glass cup and further through the water, when it hits the straw the light causes distortion of the appearance of the straw.
Refracting telescopes consist of a convex objective lens at the end of a hollow tube to diffract or change the path of incoming light waves. This lens is used to collect more light than the human eye is capable of. It also has a smaller eyepiece at the other end for the light wave information to be received by us as a larger image than our naked eye can see. When light passes through the objective lens, it is refracted or bent. The light waves that enter this lens at a parallel, end up crossing over each other or meeting at a focal point. Light which enters at an angle, combines on the focal plane. It is a combination of both directions of light waves that give an image further refraction and magnification through the eyepiece (see below). The extend of the magnification itself depends on how large the telescope and lenses are. The larger the objective lens, the more light can be gathered. When the light has reached through the eyepiece, due to the converging of the light beams, the image may appear backwards or upside-down.
Reflection:
Reflection is described as the act of light rays hitting a surface and bouncing back into the same medium. This can occur on almost all surfaces with some able to reflect more light than others. The size of the angle that the light ray hits a surface is the same as the angle when it reflects off of it.
The most common and known instance of reflection is looking in a mirror. A mirror has the most reflective surface of all known surfaces on Earth. The image produced is an exact replica of what ever is being projected by the light waves. Symmetrical in every way. The distance that the object being reflected is from the mirror, is the same distance away in the reflected surface. This is caused from the light rays bouncing off of the surface of the mirror and back into the medium, sending the image directly to the eye.
A reflecting telescope involves the use of curved, angled and straight mirrors to transfer light from the entry point to the eyepiece while keeping a clear image of an object or objects. It uses these mirrors to gather light and return it along an optical point to the focus point (eyepiece). The amount of mirrors, depends on the size and quality of the telescope. A reasonable reflecting telescope will consist of a large concave mirror (primary mirror) at the opposite end of the point of light entry and an angled mirror in the central bottom end of which reflects the light through the eyepiece (see below). When light hits the primary mirror, it bounces back to a focus point called the focal plane. Due to the concave surface of the primary mirror, the light rays are angled and sent to the opposite angled mirror where they hit at a closer angle to that which they hit the primary mirror. This straight but angled mirror send the image up to the eyepiece which is then registered by the eye. Other, larger or more complicated reflecting telescopes may have the primary mirror, an angled mirror and a convex mirror, which would help gather and pinpoint the light. The point of focus in a reflecting telescope comes in when the angled mirror aims the light at the eyepiece.