TERRESTRIAL OR EARTH BASED TELESCOPES
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- THE PRISM BINOCULARS
- THE MONOCULAR TELESCOPE
- GALILEI TELESCOPE
- NEWTON TELESCOPE
- CELESTRON REFRACTOR TELESCOPE
- DOBSONIAN REFLECTOR TELESCOPE
- LOOKING AT SUNSPOTS
- EUROPEAN GIANT TELESCOPE
Below described instruments exist out off a number of
binoculars and diverse sorts of telescopes.
We can study several astronomical phenomena, such as the sunspots, mountains and
craters on the Moon, phases of Venus, sand storms on Mars, four large moons of Jupiter,
rings of Saturn, double stars, stars and nebulae in our galaxy, comets, etc.
Look at a far object, e.g. a tower of a church. To get a sharp image with this binocular, you have to adjust the distance between the objective (object glass) and ocular (eyeglass) via middle rings.
The binoculars consists of a pair telescopes. The telescope is a Dutch invention made by two men in Middelbug in the Netherlands, namely Jansen and Lippershey (1608). This telescope was for Galilei the example for the construction of the first astronomical telescope (1609).
TECHNICAL DATA.
The represented binocular magnifies 10 times and has an objective with a diameter of 50 mm.
The field of vision of this binocular is 122. The field of vision is the number of meters, that you see around an object at a distance of 1 km of this object.
We calculate the illumination according to the formula: illumination = (diameter objective / magnification)². This binocular has a illumination of (50/10)² = 25.
By means of two light inverting prisms the image is represented for the eye in a
correct manner, for what concerns the objects at left and right, respectively above and
under in the picture.
Dutch => English
oculair => ocular
objectief => objective
de prismakijker => the binocular
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THE MONOCULAR TELESCOPE 20 x 50 mm.
Also named pirate spyglass, loved by one eyed pirate captains. Pull out the tube to full length and get a sharp image of a far object with the eyepiece ring.
With his by himself designed sort like telescope, which had a magnification of 30 x, Galilei discovered, except the mountains and valleys on the Moon, the sunspots and the four large moons of Jupiter, also that Venus as well as the Moon show phases and something particular (the ring) at Saturn. Galilei also discovered that in the telescope the galaxy dissolves itself in thousands of stars.
TECHNICAL DATA.
The represented telescope magnifies twenty times and has an objective with a diameter of 50 mm.
We calculate the illumination according to the formula: illumination = (diameter objective / magnification)². This telescope has a illumination of (50:20)² = 6.25.
Dutch
=> English
objectief => objective
oculair => ocular
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THE GALILEI TELESCOPE.
The design of this telescope is of Galileo Galilei (1564-1642). The refractor telescope consists out off an object glass (objective) and an eye glass (ocular) mounted in a tube. The picture formed by the object glass is examined with the eye glass, which works as a magnifying glass.
The astronomical telescope has an altazimuth mounting on a tripod, this means that it can be turned in an horizontal and vertical plane and for this reason also is extremely suitably for terrestrial vies of nature and the urban panorama.
Kepler improved the astronomical refractor telescope of Galilei by adding extra's, as a result of which measurements became more precise. On the basis of these measurements he reached the conclusion, that the planets move in elliptic and not in circular orbits around the sun.
TECHNICAL DATA.
The forming of the picture is based on refraction of light in lenses, therefore also the name refractor telescope.
The diameter of the objective of the represented amateur telescope is 50 mm. The length of the telescope is determinated by the focal distance of the objective and is 600 mm. More exactly said, it is the sum of the focal distances of objective and ocular.
The magnification is equal to the proportion of the focal distances of objective and ocular. With an ocular of 20 mm, resp. 6 mm we reach an enlarging of 30x, resp. 100x.
Close to the ocular is placed an inverting prism, as a result of which we can examine the erect image of objects outside the tube of the telescope.
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Dutch => English --------------------- oog => eye oculair => ocular objectief => objective licht => light |
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THE NEWTON TELESCOPE.
This reflection telescope has been designed by Sir Isaac Newton (1643-1727). The picture formed by the hollow mirror (objective) is examined by the eye glass (ocular), which works as a magnifying glass. The astronomical telescope has an equatorial mounting and as a result, it can be turned in the equator plane and an meridian plane of our earth. For this reason the telescope is extremely suitable to follow the daily celestial movements of the stars and less suitable for terrestrial observations.
Newton constructed the first mirror
or reflection telescope, which made possible a considerable larger aperture and as a
result a larger light receiving capacity. The refraction telescope of Galilei and the
reflection telescope of Newton, eventually extended with an Huygens ocular, still serve as
a main point for the construction of astronomical telescopes.
Also the laws of Kepler and Newton form still the first mental luggage of each
astronomer.
TECHNICAL DATA.
The forming of the picture is based here also on reflection in an hollow mirror, therefore also the name reflector telescope.
The diameter of the mirror of the represented amateur telescope amounts 114 mm. The focal distance of the mirror is 900 mm. With an eyepiece of 20 mm, resp. 6 mm we reach a magnification of 45x, resp. 150x. Close to the eyepiece is placed a flat mirror, which makes an angle of 45 degrees with the telescope axis, as a result of which the inverted image can be examined of the objects outside the tube of the telescope.
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Dutch => English --------------------- oog => eye oculair => ocular objectief => objective licht => light spiegel => mirror |
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Celestron NexStar 114 SLT Telescope Using Celestron's patented SkyAlign, simply input the date, time and location into the hand control then slew the telescope to any three bright celestial objects in the sky. And that's it - alignment so easy it's hard to believe! You'll spend your evening observing, not aligning your telescope!
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For more of these instruments visit Binoculars.com US and Telescopes.com US
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LightBridge Truss-Tube Dobsonian - Deluxe It's not just a big telescope. It's a big telescope that goes anywhere. New LightBridge Truss-Dobs from Meade take down and set up quickly, so you can take one of these massive windows on the universe out to your favorite dark sky location with ease. LightBridge Dobs gie you high quality Meade optics, premium components and ultra portability all for about the same price as an ordinary tube Dobsonian. So get a LightBridge Truss-Dob and prepare to cross the universe. |
For more of these instruments visit Binoculars.com US and Telescopes.com US
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The blindness of Galilei on later age is attributed to the fact, that he studied the sun with its telescope with naked eye. The ultraviolet radiation of the sun is to a great extent harmful for the retina of the human eye. Working with filters for sunlight at modern larger amateur telescopes is also discouraged, because these filters can crack by the heat of the joined sun rays (especially at high altitude of the sun) and the observer can loose an eye. More safely it is to make a image of the sun on a screen behind the eyepiece outside the telescope. Also we cannot use the viewfinder on the telescope, but the shade of this. We make this shade as small as possible, when we point the telescope to the sun.
You can also buy a solarscope to study the sun.
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ESO VERY LARGE TELESCOPE ARRAY (VLT)
The European
giant telescope (VLT) in Chile is at present the largest and most modern telescope in the world and exists off four large mirror telescopes (each 8.2 meters in diameter), which are at present fully in operation. The separate telescope entities have been linked to each other in a similar manner as our dutch Westerbork radio telescopes, on this way to produce a common image, what is much clearer and sharper than the image of each entity separate. The telescopes have Indian names, namely Antu (Sun), Kuyen (Moon), Melipal (Soutern Cross) and Yepun (Sirius).
Further technical information and pictures are
to find at the ESO site. ESO stands for European Southern Observatory. Back to MENU== 1 TERRESTRIAL TELESCOPES - EARTH BASED
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