Will Kalif asked:




The Telescope turns 400 years old this year and in four century period astronomers and telescope makers have been continually making larger and larger telescopes in order to peer deeper and deeper into the mysteries of the universe. There are currently quite a few enormous instruments in use and there are several next generation telescopes being developed that will dwarf anything currently in use. This article takes a look at some of these magnificent monsters of astronomy.

The largest Refractor telescope

Refractor telescopes are renowned for their absolute sharpness of image because they are composed of very large lenses of compounds of glass which gives them crystal clear images. But they are extraordinarily difficult to make in a large size. Their own weight distorts their shape and makes them unusable above a certain size.

The largest refractor in the world is the Yerkes telescope which has a primary lens that is 40 inches in diameter. It was completed in 1897 and was built by the famous master optician Alvan Clark. It represents the pinnacle of refractor telescope making and no larger one has since been built in the hundred years since. Reflectors are much more feasible for larger sizes and there are many of this type that are extraordinarily large. It is with reflectors that we achieve very large instruments.

Reflector Telescopes

Reflector telescopes come in two different types. The first type is the single mirror type where a single piece of glass is cast and polished to make the primary mirror. The second type is the segmented mirror where a series of hexagonal mirrors are assembled together into a single large mirror. This type of mirror looks much like the honeycomb from a beehive and this new technology is allowing telescope makers to make instruments larger than ever imagined.
The largest single piece of glass telescope in the world is the Large Binocular Telescope (LBT) in Arizona. It is a telescope composed of two separate mirrors that are side by side and work in tandem. The light from both of them are blended into one single image. Each mirror is 8.4 meters (330 inches) in width and when used together they create the equivalent of a mirror that is 11.8 meters (464 inches) across which is currently the largest light collecting size on Earth. It is located in Mount Graham International Observatory in Arizona.

Segmented mirrors pose technology challenges that have been overcome in the past decade and now these multiple mirror scopes are being built in extremely large sizes that cannot be rivaled by single piece mirrors. Of the segmented telescopes where a series of honeycomb shapes are assembled together into a single telescope there are three different observatories with these largest of mirrors.

The South African Large Telescope (SALT) is the largest primary mirror scope in the world and it has a segmented mirror that is 11 meters (433 inches) across.

The Gran Telescopio Canarias or GTC is located on the island of LaPalma Spain and it has a segmented primary mirror that is 10.4 meters in diameter (409 inches) which makes it the single largest mirror in the world.

The Keck Telescopes are a pair of telescopes located at the Keck Observatory in Hawaii. Each mirror is ten meters (400 inches) in diameter.

Bigger Telescopes to come

There are even larger telescopes currently in the proposal, development, or construction stage. Technology improvements over the past decade have made a new scale of telescope possible and this new scale is referred to as ELT or Extremely Large Telescopes and it is the next generation to come. ELT’s are telescopes that are more than twenty meters in diameter which is double the size of existing telescopes. And this doubling of size gives significantly more than double the light gathering power. Most of these scopes will be of the segmented mirror type but one notable exception is the Giant Magellan telescope which will be composed of seven spherical mirrors constructed together so they act as a single mirror. This project is scheduled for completion in 2016. It will be located in Las Companas Observatory, Chile.

The Thirty Meter Telescope (TMT), which is currently in development, will be thirty meters across and composed of segmented mirrors. It is expected to be a telescope of unmatched performance and is predicted to be able to image planets circling other stars. The current time line for this project is for it to be completed somewhere around 2017 – 2018.

What about the Famous Hubble Telescope?

The primary mirror in the Hubble is 2.4 meters across (94.5 inches) which makes it rather small compared to some of the giants listed in this article. So then why is it the most spectacular telescope ever created? The big advantage the Hubble has over all the other telescopes is that it doesn’t have to peer through the soup of Earth’s atmosphere. And this advantage is staggering. That is why the Hubble has brought us some of the most extraordinary images ever recorded.
What comes after the Hubble?

NASA is currently working on its next generation space telescope. It is called the James Webb Space Telescope (JWST). The primary mirror will be 6.5 meters (21.3 feet) in diameter. Launch is planned for 2013.

Since the invention of the first telescope 400 years ago man has been building ever larger telescopes. The telescopes to come will bring us images of planets around other stars and who knows, they may bring us images of the very birth of the universe we live in.

asked:






If you’ve found the webpage due to the fact that you’re interested in a “solar system for dummies” guide, get set to be surprised! I’ll share several constructive tips on how you can get up and running with a limitless source of free energy, and even…get paid for it. Am i dreaming? Just wait and see for yourself – keep reading this quick review.

Why make the power company richer while you count pennies if clean, green (and free) energy can be yours with a simple solar set-up, easy to build, easy to install, and quick to provide benefits? I’m please to report that it’s not costly; solar was most common on luxury homes in the “dark ages” (a couple of years ago!), but times have changed.

You may be wondering how i found all this out. I started out by doing what you’re doing – surfing the web for a “solar system for dummies” guide and i realized that while it was fairly new to me, there were many who had already “seen the light” and have been enjoying the rewards of a system which gives them the power to turn sunshine into electricity in just a couple of days. A little more research on the subject showed me that this can become a reality at what i would call a bargain basement price we can all afford (who can’t afford to save money?). Former restrictions like accessibility and cost have been removed and we can benefit from technology which gives us the ability to have plenty of clean, green energy for as long as we live.

Even if you are just interested about a “solar system for dummies” guide, take a few moments to get proof that this is all true – with solar power, you can have as much electricity as you want, at no charge, and your monthly power bill will be a thing of the past. you won’t need the electric company to supply electricity to your home. Yet another benefit of this – it’s possible to make money from the power company in your area for any surplus energy over and above what you require. And last, but certainly not least, is the fact that by generating your own energy the final reward is that you’ll be helping to improve the planet now and for centuries to come.

asked:


The first thing you might ask – what is solar radiation and how does it related to solar generated electricity? That is a good question and a topic discussed in our next article in our series dedicated to home solar power. This article, on the other hand, explains how kilowatts are calculated based upon the energy output of your solar array. We will also highlight the difference between solar cells connected in parallel versus in series.

The average American home uses about 25 kWh of electricity per day. The following example illustrates how to calculate the power produced by a residential solar energy system. Looking over a solar radiation grid, we can determine that a residence gets five daylight hours of solar radiation in one day which is then averaged out over the entire year.

Solar radiation maps are highlighted on may websites throughout the Internet. You can do a quick search for “solar radiation” to find one. In any area across the entire United States, they detail out the amount of sunshine hitting a given location based upon the time of year and its address.

Calculating the power from a solar energy system

Divide the average kWh per day by the average sun hours per day. For this example, we take 25 kWh divided by 5 hours of sun per day = 5 kW system This 5 kW system will generate 25 kWhs under optimal conditions in direct sunlight for 5 hours, or 25 kWh on an average day with some at peak production and most of the sunlight at less than optimal angles.

Future articles related to solar energy will continue to explain the effects of sun angle, reflection, and refraction on the design, output, and installation of solar panels.

Energy as it Pertains to Solar Modules

Individual solar modules that are measured in watts have a particular voltage (around 40 volts) and a particular amperage (around 5 amps). A solar module with 40 volts and 5 amps is called a 200-watt module, which means that it has the potential to produce 200 watts of electricity when in direct sunlight, away from trees or shading, and clear of snow or debris. Since most electrical components around your house are only rated for 600 volts DC, it is rare to see a solar array with a string larger the 15 solar modules. On the other hand, since inverters need a minimum voltage or pressure to turn them on, you will seldom have a solar array with a string solar modules with a size smaller then 6.

Duane Brown asked:




Ever since Galileo, people have been pointing telescopes to the heavens and expanding their view of this world by looking outside of it into other worlds. It can be a fascinating and rewarding endevour. You can even meet some very good friends this way as there are usually local star-gazing clubs within reach of almost anywhere in the country that offer plenty of companionship when using your telescope.

But how do you choose from the wide array of telescopes that are being sold today? Well, first of all you need to understand just a couple of basic points about telescopes. One is that magnification is not really the most important characteristic of a telescope. That may seem very strange, but the truth is that the most significant capability of a telescope is it’s ability to gather light. After all, what good is a large image that you can barely see?

The light gathering capability of a telescope is usually in direct relation to the size of it’s aperture or it’s light gathering lens or mirror. Now, you are probably thinking that you just need to get a telescope with the largest aperture possible then, but that is not the case. Somewhere along the line there will be a tradeoff between the size of the aperture and portability. So if you want to transport your telescope at all, you will want to make sure that it is not too heavy and bulky to be mobile. Remember that you will also most likely have to set up and adjust your telescope in the dark if your transport it, so having one that is very large can be a daunting task when you can’t see what you are doing very well.

On the magnification factor, you can adjust the magnification of almost any telescope through the use of different eyepieces, so that is not a really important consideration when buying.

It’s also important to know that there are three different kinds of telescopes, the reflector, refractor and catadioptric.

The refractor is the kind of telescope that most people think of when they think of telescopes. It essentially has a large lens on the end of a barrel that focuses an image on an eyepiece at the back of the barrel. It’s actually a very simple design, but it can also be more costly and bulky than the other styles of telescopes available. It’s good for viewing the night sky and long range here on earth, but again, it gets very expensive to produce when you want to see deep space objects.

The next kind of telescope is the reflector, and it uses mirrors to gather the light and focus it on a small eyepiece that is usually located on the side of the barrel. Mirrors are much less expensive to produce than the lenses used in refractors, so the reflector telescope is usually much less expensive as well. It is not suitable for terrestrial viewing here on earth though and it does lose a little light due to the use opf mirrors in it’s design.

The final style of telescope is the catadiaoptric which is really a blend of both refractors and reflectors, essentially taking the best of both designs with few of the drawbacks. It is a good all around selection for telescope usage as it is a good choice for both terrestrial and astronomical viewing. They may not be what you expect a telescope to look like but their design is very modern and durable.

Choosing any of these types and styles of telescopes will work depending on what you plan to use your telescope to do, and your budget. The important choice is to embark on a discovery of parts of the universe that you have never seen before.

John B Mayall asked:




Telescopes are of two main types – reflectors and refractors. The fundamental difference between both types is the kind of glasses used for light collection. Refractors use lenses while reflectors use mirrors. Going back to school physics, it is obvious that light from distant bodies, like celestial objects, comes at us as a parallel beam. Due to this parallel nature of the light rays, reflector telescopes use parabolic mirrors.

Such a parabolic mirror focuses each ray of light it receives from the original parallel beam at one single point. Because of this nature of the mirror, a reflector type telescope is far more advantageous in comparison to a refractor. A singularly important point to be noted is that reflectors do not suffer from chromatic aberrations which are a common problem for refractors. This is because, unlike refraction which alters the way in which different wavelengths are refracted, mirrors do not affect the wavelengths at all.

A second advantage is that they are relatively less expensive for the same quality of magnification. Furthermore, since light is reflected, only the reflecting surface needs a perfect finish. In the case of refractors, light has to pass form one side of the lens to the other, as a result of which both refracting surfaces need to be perfectly polished.

Astronomers generally prefer reflecting telescopes; however, even these have some disadvantages. The most glaring of these is the difficulty faced in correct alignment of the mirrors. Reflectors are equipped with an open tube, thus the inner optical elements require regular maintenance and cleaning. Without this care, images produced by the telescope end up blurred and indistinct. There are also instances of requiring secondary mirrors to correctly focus light at particular spots. These secondary mirrors can also adversely affect the image quality.

The major disadvantage faced with both refractors and reflectors is that the final image is an inverted image. An easy solution for this fault is the placement of a relay or prism in the passage of light, so that an already inverted image reaches the eyepiece, which again inverts it to produce an erect image. This is because the relay or the prism as the case may be, acts as a light ray inverter resulting in a final upright image.

The above paragraphs mention the use of secondary mirrors in reflectors to change the spot of light focus. These secondary mirrors are smaller than the primary mirror. According to historical accounts, Sir Isaac Newton used a mirror that was flat and inclined at 45 degrees as a secondary mirror. The purpose of this mirror was to shift the reflected light to an eyepiece at the side of the upper portion of the tube. This arrangement is now known as the Newtonian design and still finds takers.

There is another special design used in reflector type telescopes known as the Cassegrain design. This gives the light from the subject a specific path to reflect it better on the primary mirror. With this design it is possible to position the eyepiece at one’s own convenience. Even modern telescopes like the great Hubble Space Telescope make use of this design, and for the advantages discussed above, astronomers lean towards the reflector, and not the refractor.

CoconutScienceLab asked:

Visit my website at www.junglejoel.com – You can see Rachel at the Chabot Science Center in Oakland, California; USA. Please rate and comment, thanks!

oriontelescopes asked:

www.telescope.com In this video, the staff of Orion Telescopes & Binoculars describe how to assemble the Orion Observer 70mm AZ Refractor Telescope which works well for both daytime terrestrial viewing and nighttime astronomical use. This video also includes a comparison with the Orion Observer 60mm AZ Refractor Telescope. Visit http to find high quality products for amateur astronomers.

asked:




The federal government of Australia has established the Australian Government’s National Solar Schools Program (NSSP) to assist schools across the country to reduce their environmental impact by installing solar PV panels and solar hot water together with other sustainability measures.

The program will grant eligible schools up to $50,000 to fund the installation of solar PV panels, solar hot water systems, rain water tanks, and other energy efficient equipment. Schools who have applied before September 30th of this year will be qualified for the 2011-2012 financial year, and those who missed the application deadline can still apply for the 2012-2013 round early next year.

The program aims to deliver three major goals; reducing energy bills and saving schools money, reducing the schools environmental impacts, and to teach our children how to value the environment and how renewable energy will be a key factor in their future.

Since the commencement of the program in 2007 more than 7000 schools have registered for the program (nearly 2000 applications for 2010-2011round alone) and about 2000 schools have their new system fully installed and functional. A total of $128 million dollarshas been spent as of April 2011 for program, which will continue until June 2013.

Gundamortal asked:

unboxing telescpe from cvs

Jim Samposzi asked:




Scientists as well as hobbyists think of our galaxy as fascinating and extraordinary. The only way to view all of this astonishing creation is to view it using a telescope. This is the only one that allows for enough magnification to make planets and other things in space able to be viewed by the human eye. Some objects in space are so distant that they get classified as a distance in light years, or amount of years it takes for the seeing of this image at any given time on mother earth.

Telescopes, by design, take in light through a tube and then focused so it can be magnified. Therefore, because there are 3 methods in this, there are different telescopes that produce images in different ways. The main types of telescopes are:
Refractor – This kind is a long tube-like telescope that contains a large lens on the end called an objective lens. This kind uses a series of lenses to refract the light as it comes into the telescope where it can be viewed by the eyepiece. The objective lens on the end can be made of two or more lenses combined in just the right way for strong magnification. These telescopes are simple to keep up with and are very reliable for seeing a slough of planetary objects, stars, and galaxies. The refractor though has its limitations; one cannot view distant galaxies because the refractor is limited in ability. And, the refractor type telescopes are typically more expensive than the others. Newtonian Reflector – This type of telescope is completely different than the former in that it takes light into the lens, send it to an opposite side mirror and the reflection is focused and then sent back to the eyepiece for magnification. This type is much stronger than the others and can make it possible to see other galaxies. But, this kind needs a lot of tuning and adjustments. The Newtonian reflector, though, is known to be a bit less expensive than refractors or Catadioptric telescopes. Catadioptric – This style includes an arrangement of mirrors and lenses to manipulate beams of light onto a primary mirror and then back to the viewing lens. There is no other telescope stronger than the catadioptric. This kind can magnify pretty much any space object, galaxy, or matter. They are perfect for picking up faraway galaxies, terrestrials, and are powerful enough for terrestrial viewing and photography. This type of telescope can carry a heavy cost and look very different than Newtonian reflectors and refractors. These instruments are a fascinating piece of technology that makes it possible to see things not of this world. For centuries, people have been fascinated with space and other galaxies and universes. Telescopes make it possible for us to look up at the sky and imagine what it is like light years into the sky.