Here again are some telescope trivia for you guys!
1. Hey, did you know that telescopes were not discovered up until the 1600's. And so, before this time -- our ancient sciencists and astronomers have to make astronomical observations with their eyes, unaided by any gadgets except measuring devices. Such devices are helpful when they measure the planet's position against the background of the Stars.
So, thanks to Galileo Galilei, astronomical observations and pursuits became much easier.
2. The Hubble Telescope is the most expensive, and one of the most important telescopes created by man.
Since its creation in 1990, the Hubble Telescope has been circling the the Earth. One of Hubble Telescope's importance is providing man with vivid optical images of the space, of the planets and stars, and the Earth itself.
The Hubble Telescope was created by astronomer Edwin Hubble, whose important contribution to astronomy is the Hubble Constant.
The Hubble Constant determines the relationship between the distance of a galaxy from the Earth and the speed at which the galaxy is moving away from the earth. This constant gives a description of the rate the universe is expanding.
So, thanks to Edwin Hubble, we all know now that the galaxies are moving and moving apart, and the universe is forever expanding.
4. The Hubble Telescope is the most powerful telescope because it is stationed outside of the Earth's atmosphere. But if we are going to talk about Earth-based telescopes, the most powerful has to be the Keck Telescope in Hawaii. The Keck Telescope collects light from a number of mirrors controlled by computers. One important use of the Keck telescope is the observation of asteriods, meteors and other astronomical objects with superior carity.
Tuesday, April 18, 2006
Telescope Trivia Part 1
So, have you gotten your starter telescope yet?
Like my advise, go for the starter telescope that's light, portable, easy to set up, easy to maintain, ready for upgrading, and light on the budget.
There are many starter telescope stores in the country which offers the one that's right for everybody such as Scope City and Orion Telescopes. Why don't you check them out?
Now, let's have some bit of trivia about the telescope:
1. The smallest telescope is created by Carl Zeiss Optical. This telescope is just 4.5 inches by 1 inch in diameter - no one would notice you have it in your pocket!
Features: 10-mm lens
5x long-range magnification
10x short-range magnification
Plus feature: also serves as magnifying glass. However tiny, the telescope is magnificent in its own right!
2. The early large reflecting telescope were built by George Ellery Hale which is found in Southern California. Currently the Keck II Telescope is the world's largest reflecting telescope, which is 4 times better then Hale's reflecting telescopes in terms of gathering light.
Keck's primary mirror is 10 meters in diameter, as against Hale telescope's 5 meter primary mirror.
3. The largest refracting telescope was also build by George Ellery Hale. It is a 40-in refractor, and is housed in the Yerkes Observatory. This telescope has an aperture of 102 cm./ 40 in.
4. The most expensive telescope is the HubbleTelescope. Launched in April 25, 1990, the Hubble telescope has since then gave mankind awesome space photographs. The price of the Hubble Telescope is estimated at 7 Billion US dollars. The Hubble Telescope will remain in its orbit until the year 2010.
Like my advise, go for the starter telescope that's light, portable, easy to set up, easy to maintain, ready for upgrading, and light on the budget.
There are many starter telescope stores in the country which offers the one that's right for everybody such as Scope City and Orion Telescopes. Why don't you check them out?
Now, let's have some bit of trivia about the telescope:
1. The smallest telescope is created by Carl Zeiss Optical. This telescope is just 4.5 inches by 1 inch in diameter - no one would notice you have it in your pocket!
Features: 10-mm lens
5x long-range magnification
10x short-range magnification
Plus feature: also serves as magnifying glass. However tiny, the telescope is magnificent in its own right!
2. The early large reflecting telescope were built by George Ellery Hale which is found in Southern California. Currently the Keck II Telescope is the world's largest reflecting telescope, which is 4 times better then Hale's reflecting telescopes in terms of gathering light.
Keck's primary mirror is 10 meters in diameter, as against Hale telescope's 5 meter primary mirror.
3. The largest refracting telescope was also build by George Ellery Hale. It is a 40-in refractor, and is housed in the Yerkes Observatory. This telescope has an aperture of 102 cm./ 40 in.
4. The most expensive telescope is the HubbleTelescope. Launched in April 25, 1990, the Hubble telescope has since then gave mankind awesome space photographs. The price of the Hubble Telescope is estimated at 7 Billion US dollars. The Hubble Telescope will remain in its orbit until the year 2010.
Monday, April 17, 2006
Starter Telescope: Important Advice Before Buying
If you are into amateur astronomy, of course, one indispensable tool of the trade is the telescope.
So you are off to find and get yourself a starter telescope. You can choose between a reflector telescope and a refractor telescope, but be sure that your first starter telescope is the one that is perfect for you.
Before you get enticed by the numerous telescope retailers in the market and get pretty confused with all the varieties of starter telescope available, let’s get down to business and look to several factors that you must consider before buying your starter telescope.
First of all – is the starter telescope easy to set up? That’s one major thing to consider. Went you go out on your balcony or in the open field, you want to go out immediately and observe the skies. The last thing that you want to do is spend precious time setting up the starter telescope.
The starter telescope must be portable. It must be easy to transport from one place to another, especially if you have to bring the telescope to high places.
Of course, excellent quality of views should be delivered by your starter telescope. We all want to see vivid details of the planets and the moon, don’t we?
Even if we love our starter telescope as they are, it will come to a point that we would want a more powerful telescope. So you must make sure that your starter telescope is ready for upgrading.
We don’t pour much of our savings for a starter telescope – most are inexpensive anyway, but are still excellent in quality.
So, what are you waiting for? Check out one of those telescope retailing stores – with all these important factors in mind.
Have a great stargazing with your very own starter telescope!
So you are off to find and get yourself a starter telescope. You can choose between a reflector telescope and a refractor telescope, but be sure that your first starter telescope is the one that is perfect for you.
Before you get enticed by the numerous telescope retailers in the market and get pretty confused with all the varieties of starter telescope available, let’s get down to business and look to several factors that you must consider before buying your starter telescope.
First of all – is the starter telescope easy to set up? That’s one major thing to consider. Went you go out on your balcony or in the open field, you want to go out immediately and observe the skies. The last thing that you want to do is spend precious time setting up the starter telescope.
The starter telescope must be portable. It must be easy to transport from one place to another, especially if you have to bring the telescope to high places.
Of course, excellent quality of views should be delivered by your starter telescope. We all want to see vivid details of the planets and the moon, don’t we?
Even if we love our starter telescope as they are, it will come to a point that we would want a more powerful telescope. So you must make sure that your starter telescope is ready for upgrading.
We don’t pour much of our savings for a starter telescope – most are inexpensive anyway, but are still excellent in quality.
So, what are you waiting for? Check out one of those telescope retailing stores – with all these important factors in mind.
Have a great stargazing with your very own starter telescope!
Friday, April 14, 2006
Types of Telescopes for Astronomy
Basic Telescope Designs
The job of a telescope is to collect light, not to magnify an image (the eyepiece does that job). The larger the objective (the part that collects the light) whether it be a lens, in refractors, or a mirror, in reflectors, the more light the telescope will collect. The more light you can collect, the more detail you will be able to capture, and also important for astrophotography, the shorter your exposures will need to be to capture this detail.
Refractor Telescopes
The type of telescope most people visualize when they hear the word telescope is the 'Refractor'. This is what Galileo used for his break-thru discoveries. A refractor has an objective lens at the front which passes the light straight through to the back of the tube, focusing this light at an eyepiece or for astrophotography a camera.
Advantages:
-No central obstruction (see more in the reflecting scopes), giving higher contrast.
-Due to the simple design they require little maintenance.
-Excellent for planetary and lunar viewing and photography.
-Excellent for wide field viewing and astrophotography especially in shorter focal lengths (more on this later).
-Because the objective is permanently mounted and aligned there is no need for collimation (again more on this in another article).
-Excellent color in apochromatic and ED (Extra Dispersion) designs.
Disadvantages:
-Costlier per inch of aperture (objective) than reflectors and catadioptric telescopes.
-Can become bulky and difficult to manage, especially in larger lens designs.
Newtonian Telescopes
This design was invented by Sir Isaac Newton (he of the apple on the head fame). Instead of a lens at the front of the tube this telescope design uses a concave, parabolic mirror to collect light reflecting it back towards the front of the tube to a flat diagonal mirror which reflects the light out the side of the telescope to the eyepiece or camera for astrophotography.
Advantages:
-Lowest cost per inch of all the telescope designs.
-More light gathering power per dollar because of the lower cost design.
-Absolutely perfect color rendition.
-More compact design compared to a refractor of similar light gathering ability.
-Excellent contrast for planetary and lunar astrophotography and viewing in longer focal lengths.
-Can get excellent wide-field astrophotos and short exposures in shorter focal lengths.
Disadvantages:
-Slight loss of contrast due to the central obstruction (the flat secondary mirror) as compared to a refractor.
-Requires more maintenance, such as collimation (discussed in another article) which is vital for great results in your astrophotography, although you will learn how to do this quickly with practice.
Schmidt-Cassegrain Telescopes
This is a very popular design, with a high tech look. Also known as a CAT (Catadrioptics). They use a combination of lenses and mirrors to collect and focus the light onto the eyepiece or camera. The light enters the telescope through a thin 'lens' called a schmidt corrector plate, goes to the back of the scope to a spherical primary mirror which reflects the light back towards the front. Here the light strikes another mirror, the secondary mirror which is mounted on the corrector plate. This secondary mirror then reflects the light back towards the back where it is focused onto a hole in the primary mirror where the light is collected by an eyepiece or your astrophotography camera.
Advantages:
-Compact and portable.
-Low maintenance although once again collimation is required for top performance.
-Many, many astrophotography accessories available.
-Cheaper per inch of aperture as compared with refractors.
-Excellent all-round telescope, good to very good for both visual and astrophography.
-Very good for planetary and lunar viewing and astrophotography.
-Very good to excellent for DSO (Deep Space Object) astrophotography with a caveat (see the disadvantages).
-Very good to excellent optics, both Meade and Celestron are putting out excellent optics on a consistant basis.
Disadvantages:
-Costlier per inch of aperture as compared with Newtonian telescopes.
-Loss of contrast due to the central obstruction which is even larger than that in the Newtonian scopes.
-Due to their longer focal lengths the field of view is smaller and longer exposures are required for astrophotography, although a lens known as a focal reducer is available which minimizes or removes this problem. The longer focal length is actually an advantage in planetary and lunar photography.
Maksutov-Cassegrain
The Maksutov-Cassegrain telescope design is basically the same as the Schmidt-Cassegrain design except it uses a meniscus lens at the front instead of a Schmidt corrector plate. The main advantage to the Mak telescope design is you will get sharper higher contrast planetary and lunar images when compared with the Schmidt design.
Carl Gilbertson has been involved in amatuer astronomy for over 30 years and astrophotography for over twenty-five years. Learn more at his site: Telescopes For Astrophotography
Article Source: http://EzineArticles.com/?expert=Carl_Gilbertson
The job of a telescope is to collect light, not to magnify an image (the eyepiece does that job). The larger the objective (the part that collects the light) whether it be a lens, in refractors, or a mirror, in reflectors, the more light the telescope will collect. The more light you can collect, the more detail you will be able to capture, and also important for astrophotography, the shorter your exposures will need to be to capture this detail.
Refractor Telescopes
The type of telescope most people visualize when they hear the word telescope is the 'Refractor'. This is what Galileo used for his break-thru discoveries. A refractor has an objective lens at the front which passes the light straight through to the back of the tube, focusing this light at an eyepiece or for astrophotography a camera.
Advantages:
-No central obstruction (see more in the reflecting scopes), giving higher contrast.
-Due to the simple design they require little maintenance.
-Excellent for planetary and lunar viewing and photography.
-Excellent for wide field viewing and astrophotography especially in shorter focal lengths (more on this later).
-Because the objective is permanently mounted and aligned there is no need for collimation (again more on this in another article).
-Excellent color in apochromatic and ED (Extra Dispersion) designs.
Disadvantages:
-Costlier per inch of aperture (objective) than reflectors and catadioptric telescopes.
-Can become bulky and difficult to manage, especially in larger lens designs.
Newtonian Telescopes
This design was invented by Sir Isaac Newton (he of the apple on the head fame). Instead of a lens at the front of the tube this telescope design uses a concave, parabolic mirror to collect light reflecting it back towards the front of the tube to a flat diagonal mirror which reflects the light out the side of the telescope to the eyepiece or camera for astrophotography.
Advantages:
-Lowest cost per inch of all the telescope designs.
-More light gathering power per dollar because of the lower cost design.
-Absolutely perfect color rendition.
-More compact design compared to a refractor of similar light gathering ability.
-Excellent contrast for planetary and lunar astrophotography and viewing in longer focal lengths.
-Can get excellent wide-field astrophotos and short exposures in shorter focal lengths.
Disadvantages:
-Slight loss of contrast due to the central obstruction (the flat secondary mirror) as compared to a refractor.
-Requires more maintenance, such as collimation (discussed in another article) which is vital for great results in your astrophotography, although you will learn how to do this quickly with practice.
Schmidt-Cassegrain Telescopes
This is a very popular design, with a high tech look. Also known as a CAT (Catadrioptics). They use a combination of lenses and mirrors to collect and focus the light onto the eyepiece or camera. The light enters the telescope through a thin 'lens' called a schmidt corrector plate, goes to the back of the scope to a spherical primary mirror which reflects the light back towards the front. Here the light strikes another mirror, the secondary mirror which is mounted on the corrector plate. This secondary mirror then reflects the light back towards the back where it is focused onto a hole in the primary mirror where the light is collected by an eyepiece or your astrophotography camera.
Advantages:
-Compact and portable.
-Low maintenance although once again collimation is required for top performance.
-Many, many astrophotography accessories available.
-Cheaper per inch of aperture as compared with refractors.
-Excellent all-round telescope, good to very good for both visual and astrophography.
-Very good for planetary and lunar viewing and astrophotography.
-Very good to excellent for DSO (Deep Space Object) astrophotography with a caveat (see the disadvantages).
-Very good to excellent optics, both Meade and Celestron are putting out excellent optics on a consistant basis.
Disadvantages:
-Costlier per inch of aperture as compared with Newtonian telescopes.
-Loss of contrast due to the central obstruction which is even larger than that in the Newtonian scopes.
-Due to their longer focal lengths the field of view is smaller and longer exposures are required for astrophotography, although a lens known as a focal reducer is available which minimizes or removes this problem. The longer focal length is actually an advantage in planetary and lunar photography.
Maksutov-Cassegrain
The Maksutov-Cassegrain telescope design is basically the same as the Schmidt-Cassegrain design except it uses a meniscus lens at the front instead of a Schmidt corrector plate. The main advantage to the Mak telescope design is you will get sharper higher contrast planetary and lunar images when compared with the Schmidt design.
Carl Gilbertson has been involved in amatuer astronomy for over 30 years and astrophotography for over twenty-five years. Learn more at his site: Telescopes For Astrophotography
Article Source: http://EzineArticles.com/?expert=Carl_Gilbertson
Reflecting Telescope
The reflecting telescope is an optical type which employs both curved and flat mirrors to create an image, as opposed to the refracting telescope with uses lenses to bend light to create an image.Originally an idea of the Italian religious Niccolo Zucchi, the first reflecting telescope was invented on 1670 b y Sir Isaac Newton. Because of the inferior quality of the refracting telescope, Newton designed the reflecting telescope, which is traditionally double-mirrored.
Focus designs of reflecting telescopes:
1. Newtonian focus - by Newton, is the focus for reflecting telescope for which the focal point lies to the side of the telescope. The reflecting telescope receives the light and is reflected from the first mirror to a second mirror midway the telescope tube. The second mirror of the reflecting telescope directs the light to the side of the telescope.
Nowadays, this focus design by Newton is only popular in amateur and hobby astronomy.
Professional astronomers and scientists prefer to ulitize the Cassegrain focus and Prime focus designs of the reflecting telescopes.
2. Cassegrain focus - has a parabolic first mirror, and a hyperbolic second mirror that bounces off the light back to the hole in the first mirror.
3.Prime focus - here, the observer sits inside the reflecting telescope, at the focal point of the reflected light.
4. Coude focus - is quite the same as the Cassegrain, except that there is no hole in the primary mirror, and there is a third mirror that reflects the light to the side, and other optics deliver the light to a fixed focus point. The Coude focus design as utilized on observatory telescopes.
Source: Wikipedia - License: GNU FDL
Telescope: An Introduction
The partnership between astronomy and the telescope goes a long way.
Few facts and trivia on the telescope:
1. Dutch eyeglass maker Hans Lippershey was credited as the inventor of the first telescope and is also sometimes credited with the invention of the compound microscope.
2. The telescope as first used in the field of astronomy by Galileo Galilei. Through his crude telescope, Galileo became the first scientist of observe the moons features, particularly the craters and mountains and other planets in our solar system.
3. Sir Isaac Newton invented in 1704 a telescope which used a curved mirror designed to collect the light coming in and bounce it back to a focused point. Called the reflector telescope, it magnifies objects a million times better than an ordinary lens used by Galileo.
4. There are two types of telescopes:
a. The Optical telescopes, which are of two kinds:
i. Galilean refracting telescopes - works under the refractive properties of light. Refracting telescopes are made of lenses.
ii. Newtonian reflecting telescopes - employs light's reflective properties. Reflecting telescopes on the other hand uses are made of lenses and mirrors. These telescopes are more used for astronomical purposes and studies.
b. The Radio telescopes - are sensitive to radio waves given off by radio sources. Radio telescopes are in the form of huge disk antenna.
Whether you are a scientist, an astronomy hobbyist or a kid interested in studying the planets and stars up the heaven, then the telescope is a must intrument to own. From the simple to the complicated telescope equipment, everyone has a particular and unique telescope that fits one's needs.
Few facts and trivia on the telescope:
1. Dutch eyeglass maker Hans Lippershey was credited as the inventor of the first telescope and is also sometimes credited with the invention of the compound microscope.
2. The telescope as first used in the field of astronomy by Galileo Galilei. Through his crude telescope, Galileo became the first scientist of observe the moons features, particularly the craters and mountains and other planets in our solar system.
3. Sir Isaac Newton invented in 1704 a telescope which used a curved mirror designed to collect the light coming in and bounce it back to a focused point. Called the reflector telescope, it magnifies objects a million times better than an ordinary lens used by Galileo.
4. There are two types of telescopes:
a. The Optical telescopes, which are of two kinds:
i. Galilean refracting telescopes - works under the refractive properties of light. Refracting telescopes are made of lenses.
ii. Newtonian reflecting telescopes - employs light's reflective properties. Reflecting telescopes on the other hand uses are made of lenses and mirrors. These telescopes are more used for astronomical purposes and studies.
b. The Radio telescopes - are sensitive to radio waves given off by radio sources. Radio telescopes are in the form of huge disk antenna.
Whether you are a scientist, an astronomy hobbyist or a kid interested in studying the planets and stars up the heaven, then the telescope is a must intrument to own. From the simple to the complicated telescope equipment, everyone has a particular and unique telescope that fits one's needs.
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