Articles of Science

Surprise Factor in How Stars Die: Sodium

noreply@blogger.com (Unknown) — Thu, 30 May 2013 09:56:00 +0000

The sodium content of sunlike stars determines if they skip a phase of death.

Scientists studied the sodium content of stars in the cluster known as NGC 6752.

Image courtesy ESA/NASA

The way that stars spend their last years is largely shaped by their sodium "diet," according to a surprising new study published on Wednesday.

The study could upend current theories about how some stars that are similar to our sun die and become the basic building blocks for the next generation of stars and planets.

According to existing stellar evolution models, sunlike stars—those that are similar in size and chemical composition to our sun—swell to become so-called red giants in their final stage of life, before losing their atmospheres in a spectacular bubble of gas and dust.

This fate awaits our own sun in 4 to 5 billion years, scientists say.

The final period in a sunlike star's life, when stars make their greatest contribution to the universe, is known as the asymptotic giant branch (AGB).

"They puff off all their outer layers of gas and dust, enriching and polluting the surrounding space," said Simon Campbell, an astronomer at Monash University in Australia and the co-author of the new study published in the journal Nature.

"This gas and dust gets recycled and goes into the formation of the next generation of stars, planets—and possibly even life."

But now astronomers have found that not all sunlike stars follow the same rules when it comes to the end of their life cycles, and that some can skip the AGB phase altogether.

Chemical Fingerprints

Campbell and his team studied a giant ball of stars known as NGC 6752, one of the sky's brightest globular clusters. The collection of about one million stars sits 13,000 light-years from Earth in the southern constellation Pavo.

Globular clusters are considered the perfect cosmic laboratories for studying stars and testing stellar computer models because they have so many stars, in all phases of life.

Campbell's team used the European Southern Observatory's Very Large Telescope in the Atacama Desert of Chile. The giant telescope was equipped with a spectrograph—a prism used to break starlight into its colors—which allowed the researchers to obtain the chemical fingerprints of 130 cluster stars at once.

The team immediately noticed that the cluster is home to both a first generation of stars, at least 10 billion years old, and a second generation that is billions of years younger—and that the two groups appeared to contain different amounts of sodium.

"It's a bit like using sodium as a chemical 'tag' to follow each population of stars," said Campbell.

By tracking the sodium levels, the researchers were able to identify which stars would undergo the AGB phase at the end of their lives.

"We suspected sodium might be a good 'tracer' because it cannot be altered by the stars themselves because they are too low mass, and not hot enough to create or burn sodium," Campbell said.

His team quickly realized that some members of the cluster didn't appear to follow accepted theories when it came to undergoing the final burn stages, or AGB, when they were dying. Some skipped this final burst of nuclear burning entirely.

All the AGB stars in the study were first-generation stars with low levels of sodium, while none of the higher-sodium second-generation stars had become AGB stars.

It turns out that up to 70 percent of the stars in the NGC 6752 cluster were not undergoing the final "nuclear burning and mass-loss phase so indicative of sunlike stars," said Campbell.

Stellar Mystery

Exactly why there are two broad groups of stars with starkly different sodium levels in globular clusters is still unknown, Campbell said, and is a hot topic in stellar research.

How the newfound breed of sodium-rich, sunlike stars ultimately die is still something of a mystery. Campbell suspects they may directly evolve into small-Earth-size white dwarf stars that gradually cool over many billions of years.

But he said that one thing's for sure: Existing computer models of how sunlike stars die will need to be adjusted.

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Acrotholus, New Dinosaur Species Amounting Dog

noreply@blogger.com (Unknown) — Thu, 30 May 2013 09:28:00 +0000

Illustration Acrotholus audeti. (Julius Csotonyi / Phys.org)

With a length of about 1.8 meters and weighing 40 kilograms, this dinosaur is a dinosaur skull hard oldest in North America

Scientists finally give a name Acrotholus audeti on pachycephalosaur, or species of dinosaur skull hard origin Alberta, Canada. Certainty Acrotholus a new species was confirmed from the latest fossils were found and which has been obtained so far.

With a length of about 1.8 meters and weighing 40 kilograms, this plant-eating dinosaur is hard oldest dinosaur skulls that were found in North America, and possibly also the oldest in the world. Full details of audeti own Acrotholus published in the journal Nature Communications.

"Acrotholus presenting new information related to the evolution of dinosaur skull hard. Although he is one of the oldest members of this family, surprisingly, that thick skull dome has developed very well in the geological era, "said David Evans, head of the research team.
Evans says, the more important of these findings is that the track record of fossils obtained, these animals showed that we are just beginning to understand the diversity of small plant-eating dinosaur.

Acrotholus name itself means "high dome", which follow the shape of his skull like a dome. The skull consists of dense bone with a thickness of more than ten centimeters. The audeti taken from the name Roy Audet, landowners where specimens of dinosaur fossils were first discovered in 2008.

Acrotholus walking on two legs. Dome-shaped skull above the eyes of these animals may be used to compete with each other head during his lifetime. Expected, Acrotholus alone lived about 85 million years ago.

"We predict that there will be many other such small dinosaur species found Acrotholus in the future if researchers want to sort the bones of animals that they find in the field," said Michael Ryan, curator of the Cleveland Museum of Natural History.
These findings, says Ryan, also emphasized the importance of landowners like Roy Audet allow their land to be studied by scientists in order to generate a lot of important findings. Fossils Acrotholus Audeti itself began on public display at the Royal Ontario Museum,
Canada, in May 2013 this month.

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Why Penguins Can not Fly?

noreply@blogger.com (Unknown) — Tue, 28 May 2013 21:54:00 +0000

Penguin wings have been converted, which is used as a tool to bring to swim rather than taking off. Penguins have lost their flying ability eons ago. Why?

Recent studies have assumed that the penguin sea birds stop flying as a result of evolutionary processes, which make the penguin must adapt to the environment, which is a master swimmer. According to a study published in the Proceedings of the National Academy of Sciences May 20 issue, the penguin needs to swim in the middle of a competitive environment.

May fly, for some aspects, is an advantage for the penguins who live at the South Pole, for example when escaping predators or when the parade emperor penguin colony that can be up to many days.

However, reiterated by Katsufumi Sato, an expert in the field of behavioral ecology Ocean Research Institute-University of Tokyo, this happens because of evolution. Penguins evolved into a larger body sizes that need a crutch when diving in the water.

For the sake of this important reason, experienced reduced progressive wing, which makes swimming more efficient and when used to fly instead. This could be the answer to why it was then that the ability of penguins to fly gradually disappeared.

Sato is an ecologist at the National Geographic Society Emerging Explorer is also explained, the larger body allows them to dive longer. When opportunities in transition where the wings used for flying or diving, which occurs even harmful to penguins due to waste energy and can not last long.

Julia Clarke, a researcher who focuses on the evolution of birds from the University of Texas at Austin, revealed no differences were found in penguins in origin. However, little relevant data that can be used to develop it. This latest discovery could be a key in the explanation of the transition from the model of "wings" to the "fin" penguin.

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In Earth's Layers Temperature Equivalent Surface of the Sun

noreply@blogger.com (Unknown) — Tue, 28 May 2013 21:50:00 +0000

Layer in the Earth's temperature 1,000 degrees celsius apparently higher than previously thought. Based on the latest measurements, the surface temperature in the only planet that can support life proved equivalent to the complex surface of the Sun, 6,000 degrees celsius.

The measurement results obtained by the research team of French scientists Sciences Institute (CNRS) and several other institutions. Temperature in the layer, on the border of the inside and outside of the Earth, estimated from measurements of the melting point of iron.

Through these measurements, researchers actually want to shed light on the formation of the Earth's magnetic field. To have a strong magnetic field, there must be a difference in the temperature of 1500 degrees Celsius between the inner and outer layers.

Researchers are already making measurements boundary layer temperature inside and outside the Earth before. However, the measured temperature differences previously showed no significant difference. Through this study, researchers conducted repeated measurements.

Measurements of the melting point of iron in the study done by exploiting the properties of diffraction (spreading) X-ray When mashing the X-ray iron, then there will be a "sign" that the heated iron.

From these measurements, as reported by LiveScience, Friday (26/04/2013), showed that the melting point of iron is 4,800 degrees Celsius, the pressure is 2.2 million times greater than the pressure above the Earth's sea level.

Based on these results, the estimated temperature of the layer that limits the inside and outside of the Earth is 6000 degrees celsius. The results published in the journal Science on Thursday (04/25/2013). The research results useful for seismologists to estimate plate motions Earth.

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Scientists Will Use Boats To Explore the lake on Titan

noreply@blogger.com (Unknown) — Tue, 09 Oct 2012 23:01:00 +0000

Composite photograph Titan taken by the Cassini spacecraft. Image credit: NASA

When ground vehicles ideal for the exploration of Mars, the ship or boat is the best means to explore Titan, the largest moon of Saturn. Scientists have recently submitted a proposal on a new mission to explore the lake on Titan.

Titan is one of the 60 months that is owned by the Planet Saturn. Titan has a wide range of things that are not owned by months or even other planets in our solar system. It is like the ocean, lakes, and streams consisting of methane, and it has a thick atmosphere that makes Titan an object in the solar system most similar to Earth. Smaller size of the Earth but larger than Mercury.

Until now, scientists do not know whether there is life on Titan, because there are very cold temperatures reaching minus 178 degrees Celsius. But there can be no life on underwater micro-organisms. That's what makes scientists very curious and wanted to explore Titan's picture in recent years often perpetuated by the Cassini spacecraft orbiting Saturn. ESA's Huygens orbiter spacecraft ever landed on Titan also had to submit photos Titan's surface before it lost contact.

From the information that was obtained from the Huygens spacecraft, it is known that Titan has lakes, rivers, and oceans of hydrocarbons are very abundant. From there scientists proposed Titan Lake In-situ Sampling Propelled Explorer (Talise) in the form of a boat driven by a kind of "windmill" to float on the lake Ligeia Mare, the largest lake in Titan's north pole located on Saturn's largest moon is. Once relegated to the lake, then Talise will move to the edge of the lake. Here is a picture of the vehicle design Talise:

Draft Talise vehicle used to explore the lakes on Titan. Image credit: SENER

Talise itself is gambungan project with Centro de Astrobiología SENER of Spain. New concept in the early stages and was presented by scientists on the 27 September 2012 and at the E uropean Planetary Science Congress held in Madrid, Spain. (SP, Adi Saputro / www.astronomi.us)

The U.S. flag was still there on the Moon

noreply@blogger.com (Unknown) — Tue, 09 Oct 2012 22:05:00 +0000

Extraordinary! The phrase was uttered spontaneously after LRO satellite images in a resolution never before obtained a resounding success reveals one of the great puzzles of the saga of human landing on the Moon: the fate of the flag planted on the ground Month. Throughout human landing on the Moon missions that have lasted up to six times in the period 1969 to 1972 in the form of missions Apollo 11 through Apollo 17, except for Apollo 13 oxygen tank explosion that had the command module so that the moon landings were canceled, there is also a six flags has been plugged in every point landing. Overall is the U.S. flag.

U.S. Flag on human landing on the Moon, the Apollo missions 15 (left) and Apollo 17 (right), taken at nearly the same distance. Sources: NASA, 1971 & 1972.

Flag to be one of the hot topics in the discourse of human landing on the Moon. The skeptic presents flag "fly" (while true form of static stretching flag) as one reason for the denial of landing humans on the Moon and considered nonsense and deception model of the Cold War. Instead the optimists think the flag poles live without fabric. For the base material of nylon, it is difficult to imagine how the fabric flags can survive in harsh environments month. Over the past four decades, cloth flags are in vacuum conditions with exposure to extreme heat as high as 100 degrees Celsius during the month (over 14 Earth days) and then followed by exposure to very cold freeze (as low as minus 180 degrees Celsius) at night the Moon (all 14 days Earth too) with exposure to excessive ultraviolet rays sun, cosmic rays from the Sun and from across and micrometeorites. With such a harsh environment, it's no wonder many are meranmalkan cloth flag on the Moon has terkelantang, degraded, torn, or even terdesintegrasi so that it crumbled to dust.

Condition flag carried in the human landing on the moon mission in folded condition two before installed. On the right top is the top of the flagpole with a folded-over penyiku and already terpasangi flag. Meanwhile, at the bottom is the bottom of the flag pole driven into the ground wishing Month with two notches markers indicating a limit to how far this can go in part to the ground Month. On the right is a hinge lock for penyiku-up, while on the left is the key liaison for the top and bottom of the flag pole. Sources: NASA, 1969

Is this true?

Satellite launch moon probe LRO (Lunar Orbiter Reconaissance) on June 18, 2009 offers the opportunity to analyze how the fate of flags planted on the lunar surface indirectly. The satellite is intended to map global topography of the Moon, characterize the space radiation in lunar orbit and explore the moon's poles to look for the possibility of the existence of water on the Moon brings a very high resolution camera that is able to identify objects up to the size of 0.5 meters in height thanks to the Moon orbit ( which is only 50 km from the surface of the Moon) and the nature of its orbit (orbit polar / polar). These capabilities make the LRO satellite for the first time been able to identify the traces left in the program four decades ago human landing on the Moon. The trail includes the rest of the modules Month, the scientific investigation, footprints of astronauts and furrows moon rover vehicle wheel.

Flag of the Moon really is not a target of the investigation LRO, because the flag pole diameter is only 2 cm, it is difficult to identify in the LRO images. The only way possible is to detect shadow flag cloth under the hot sun. With a cloth flag size 1.5 meters x 1 meter for Apollo 11 through 15, then the shadow of the flag fabric can be detected LRO satellite cameras. By taking a number of images in any lighting condition the Sun, for example, since after sunrise, low altitude of the Moon in the eastern sky, low altitude in the western sky moon up ahead of the sunset, the shadow of the flag followed how the dynamics can be studied so that the location of the flag can be ascertained. Of course with a note if cloth flag was still there.

In addition it should be noted also notes Edwin Aldrin, Apollo 11 astronauts. In his book Return to Earth as thick as 239 pages, Aldrin said that upheld flag with Neil Armstrong on Mare Transquilitatis, with a flag pole along the 2.7 meter by 0.6 meter plugged them into the land of the Moon, has collapsed due to its position so close to the moon module. So that when the module is turned back (to return to Earth), powerful bursts gasbuang cause fabric flag with pole crashed to the ground. LRO satellite imagery is indeed confirmed Aldrin records.

So the only remaining five-point just where the flag may still remain. From the fifth point, LRO is brilliantly able to identify the flag (actually a shadow flag) at three points, namely at the landing site of Apollo 12, Apollo 16 and Apollo 17.

On the Apollo 12 landing site, a flag planted with locking hinge mechanism on penyiku-up was damaged, so the fabric flags became limp, not stretched as well as the flag on the Apollo 11 landing point. Still in the land of the shadow of the Moon flag fabric printed clearly. Based on the image of the Apollo 12 astronauts, high at the sun 10 degrees above the eastern horizon, the shadow of the flag fabric stretches as far as 2.8 meters up to 12 meters from the base of the flagpole. With land at Moon landing site tend to be flat, shade cloth flag on the Apollo 12 landing site is quite clearly seen in the LRO images. By the time the sun just rising (high sun only 8 degrees above the eastern horizon), shade cloth banner stretched up along the 15 meters to the west. Similarly, when the sun goes down approach (high sun 6 degrees above the western horizon), shade cloth flags stretching up to 20 meters, this time to the east.

Animation Apollo 12 landing site and shade cloth flag, composed by five LRO satellite images, each taken in different lighting, ie when the sun high above 8 degrees east horizon, 32 degrees above the eastern horizon, 59 degrees above the western horizon, 9 degrees above the western horizon and 6 degrees above the western horizon. Sources: NASA, 2012.

While the Apollo 16 landing site, the locking hinge mechanism works well so that the fabric can be stretched like a flag should have been. However, due to the module is installed too close to the Moon, gasbuang bursts when the module restarts cause flagpole tilted up to 30 degrees. Thus, the shadow of the flag of the resulting fabric is not as long a shadow cloth flag at the landing site of Apollo 12. However LRO satellite able to identify it properly.

Animation Apollo 16 landing site and shade cloth flag, composed by seven LRO satellite images, each taken in different lighting, ie when the sun high above 8 degrees east horizon, 10 degrees above the eastern horizon, 43 degrees above the eastern horizon, 69 degrees above the eastern horizon, 61 degrees above the western horizon, 7 degrees above the western horizon and 2 degrees above the western horizon. Sources: NASA, 2012.

It is also common at the Apollo 17 landing site. Flag cloth size 20% larger than the other with a flagpole stuck deeper, so that they can survive without shifting / tilt modules when exposed to bursts gasbuang month when switched on again. This makes satellite LRO was able to identify the flag with fabric shade well.

Animation Apollo 17 landing site and shade cloth flag, composed by six LRO satellite images, each taken in different lighting, ie when the sun high above 8 degrees east horizon, 11 degrees above the eastern horizon, 35 degrees above the eastern horizon, 68 degrees above the eastern horizon, 26 degrees above the western horizon and 5 degrees above the western horizon. Sources: NASA, 2012.

What about the fate of the flag at the landing site of Apollo 14 and Apollo 15? The photos of the Apollo 14 astronauts indicates flag is mounted in place pushed it into the stretched condition when the moon module restarts. Even in the case of Apollo 15 landing site. But could not identify the LRO satellite shadow cloth flag in both the landing site. What cause is still unclear, although allegations have been degraded to the flag off of the pole or the lighting conditions when the Sun is less support LRO to image.

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Why Kuiper Belt Object Observed More Difficult?

noreply@blogger.com (Unknown) — Tue, 09 Oct 2012 21:53:00 +0000

Illustration of Objects in the Kuiper Belt. Credit: UCLA

It seems strange not, really see distant stars and even galaxies far away it could be done but to find and identify celestial bodies in the Kuiper Belt was difficult. Lest astronomers had only made it up. Logically it seems odd that we are only based on the distance of an object. Is not it easier to find items close than far away? But in fact if traced further, it is not strange. Because the same thing could happen in everyday life on Earth.
To observe objects in the universe, distance is not the main issue. In everyday life, how can we see an object? Using the eye is not? So to be able to see an object the cornea must receive light from the light source and then forwarded to the pupil of the eye to the retina. Without sunlight will not be able to identify an object.
The same thing happens in observing celestial objects. But, to make observations of celestial objects, our eyes have limited and only able to see objects up to a 6 magnitude brightness. That requires tools such as the telescope was first used by Galileo to look at the heavens 400 years ago.
Telescope into a tool that can bring people see things - a very distant celestial bodies. But it must be remembered that the function of the telescope with the eye. The telescope is essentially a tool for gathering light, strengthen, and collecting it in one place. Although the word "telescope" can be broken down into "tele" meaning "far" and "scope" means "look" or less meaning is "to see [the objects] away", but the main function of an astronomical telescope is not to look up to distance.
Why we are "easier" to see stars that are very far while the Kuiper belt objects in the Solar System is difficult to identify?
The answer lies in the source of light.
Star is located very far from Earth. Nearest star from Earth is the Sun and stars near the Sun next 4 light years away. There are even further and can be observed using a telescope. This is because the star has its own light source that despite being away can still be seen. So although distant objects but emits its own light source (and strong), it will be easy to spot, than close, but dim and does not emit its own light.
In the solar system, planets and other objects orbiting the Sun does not emit its own light. They receive light from the sun and then reflect it. That is why we can see the planets in the Solar System. But, the farther an object is from the light source the less that can be received and reflected back. That's what happened with the objects in the Kuiper Belt. Its location on the outer area of the solar system clear away from the light source (the Sun) that there is no light that can be collected to be seen. Or in other words in the Kuiper Belt objects are very faint.
Like when the power goes out when we're at home, then the objects around us we can not see but a very distant object on the other side of the road we can see even though only a dim lit.
Kuiper Belt over the years into an area that is only in theory, and only discovered in 1992. The objects in the Kuiper Belt is 30 AU from the orbit of Neptune and has more than 70,000 objects trans-Neptnunian with a diameter of more than 100 km. The discovery of an object in the Kuiper Belt is believed to be a high priority because the objects in the Kuiper Belt are still storing the material forming the solar system, so we can know how the beginning of the solar system before the planets formed.
Currently, in order to study the area in the Kuiper Belt Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) PS1 did a survey in the area to be able to find very faint objects in the area that is located 50 AU from the Sun. Pan-STARRS telescope is 1.8 meters by 1.4 giga pixel kamer (1400 mega pixels).

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Crows can distinguish Friends and Enemies

noreply@blogger.com (Unknown) — Fri, 05 Oct 2012 08:31:00 +0000

Brain scans show how the crow distinguish friend from foe. You learn from the crow that you have done wrong, but you can not hide from them.

Wild crows remember the human face in the same way mammals do. American crow Corvus brachyrhynchos distinguish human faces and remember how different people treat them.

John Marzluff, environmentalists University of Washington in Seattle, and colleagues used a latex mask while catching 12 liarCorvus brachyrhynchos crow.

Crow learns to associate the mask kidnappers with a traumatic experience. While in captivity, the ravens fed and see people wearing different masks.

After 4 weeks of brain scans done when they saw the kidnapper or mask feeding. The pattern looks similar to the mammalian brain.

Mask feeding area event trigger motivation and reward. Meanwhile, kidnappers stimulate display area associated with fear.

Tips to Buying a Telescope

noreply@blogger.com (Unknown) — Tue, 25 Sep 2012 11:51:00 +0000

Buying a telescope is certainly a lot of his or her choice. Starting from the telescope that cost hundreds of thousands to hundreds of millions. Before unpacking more about tips on buying a telescope, will advance in the mentioned restrictions on telescope that will be purchased include:

Decent telescope for astronomical observations.
Telescopes bought in intended for users with beginner to intermediate level.

Telescope, For What?

Did not know it was love. That is the most fitting expression when we are dealing with something that we have. Before we buy a telescope, it would be better we know in advance what it is about telescopes. Instrumentation astronomical telescope is used to view celestial objects at great distances. Celestial objects could be the moon, stars, galaxies, star clusters and nebulae. The telescope is generally known as binocular telescopes nevertheless also allows you to see objects that exist on the surface of the earth as seen the mountain top, the bird perched in a tree and shoot a tiger at a distance of 100 meters. The telescope that we use have two types namely the type refractor telescope that uses a lens or as a light collector and reflector type of telescope that uses a mirror as a light collector. Both types of telescope has advantages and disadvantages. Type refractor telescope is perfect for observation planetary sky objects such as the moon, planets (Mercury, Venus, Mars, Jupiter and Saturn), and the star was a reflector telescope is perfect for observing objects that have sky lights dim as the galaxy, star clusters and nebulae. Well after we know the types of telescopes and its advantages, now you want to know what type of telescope? Refractor telescope suitable for planetary object or reflector telescope suitable for observation of faint celestial objects (galaxies, star clusters and nebulae)

Telescope tube

Such as motorcycles, the telescope tube is the engine of the motorcycle. In general the telescope tube is already contained several components such as lenses (refractor), mirror (reflector) and focusser. Her bad either a telescope in displaying an object is determined by the quality of the light collecting media (read: the lens or mirror). At refractor telescope, the lens will be a very vital when you do not notice. One just choose the lens you choose the quality of the resulting picture will be different. Good lens is a lens made of glass and has been coated with the coating (Coating). Decent lens coatings or coating for his general observations have been using magnesium fluoride coating materials so that the coating is the quality of the resulting picture will be sharper and better than lenses that are not in the coating. If your funds allow, choose a telescope that has been using this type of lens Apocromatik or often called ED lens (his regular on a series of such brands telescope ED120). ED lenses or extra dispersion Low quality lenses that can divide three types of waves generated colors so images are very sharp and clear than the telescope that is still using cromatik lens which can only divide the two waves of color.

In a telescope lens coating greenish color

Diameter of the light collectors

Both lenses and mirrors, her large diameter is one of the light gathering power of the telescope. The larger the diameter of the lens or mirror, the greater the light collected. Many of his light that we can gather through a telescope will clarify the shape of the image celestial objects. Celestial objects have a weak magnitude as nebulae and galaxies requires a large enough diameter. In reflecting telescope, the mirror diameter is generally larger due to light-functionalized weak light can be caught. But there are also refractor telescope that has a large diameter. For comparison a very sharp, when you have money 2.5 Million, you will be able to have a refractor telescope with a diameter of about 80 mm but if you buy you will get a reflector telescope reflector telescope with a diameter of approximately 130 mm.

F the caretaker enlargement

F or focal length or more popularly as the focal length is a power of two telescopes after diameter. The longer the larger F magnifying. Sentences just have a general formula in the world of astronomy. The meaning of the sentence is longer exposed lies the focal point of the lens or mirror the greater the enlargement resulting from a telescope when we look at using the eyepiece. Magnification telescope has a formula, magnification = F Objective: F eyepiece. Enlargement will be generated when the focal length of the objective lens divided by the focal length of the eyepiece. Focal length has units of millimeters (mm), but there is also a mention of his like F / 4 which means that F is generated has a length of four times the length of the diameter of the objective lens.
If we compare between refractor and reflector, refractor his general long-term F is greater than the reflector. F refractor has a longer, that's why refractor is very suitable to be applied to planetary objects such as the moon, planets, and stars a strong magnitude. Planetary objects has a magnitude that is strong enough so that the light gathering is not so noted and the observation magnification planetary objects are more dominant than light gathering.
Broadly speaking, I formulated in choosing a telescope. Good telescope is a telescope that has a large diameter and has a long F. But again I say, If you want to buy a telescope object first decide what you want to observe more dominant? If it is a planetary objects such as the moon, planets (Mercury, Venus, Mars, Jupiter and Saturn), and air-magnitude star options are powerful refractor telescope, but if you want to observe objects such deepsky Galaxies, nebulae and star clusters reflector telescope is a great choice appropriate. You need to know refractor telescope can also be used to view galaxy, nebula and star clusters although not as good as the reflector so its reverse reflector telescope also allows you to view the moon, planets (Mercury, Venus, Mars, Jupiter and Saturn) and the stars.

Mounting telescope

Mounting or better known as the cradle familiar telescope is divided into two types: type mounting equatorial and altazimuth mounting types. Mounting Equatorial works using 3 pieces axis is the axis of RA, Declination and the Equator. 'm Using 2 pieces altazimuth mounting axis is the x axis or altitude (up and down) and the Y or the azimuth (left-right). For operation of an altazimuth mounting is much easier than the equatorial mounting. When you next want to seriously study astronomy the equatorial mounting option is the right choice.

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Gaby - pernah ada

noreply@blogger.com (Egi) — Sun, 03 Jun 2012 12:15:00 +0000

Before i had, the feeling of love, between us is now a distant memory...
I want to forget, all about you...
But no again, she will be like you, oh my star...

Reff:
Away you go, you go without myself..
I am here, I always miss yourself...
I want to try to find a replacement you...
But no again, she will be like you, oh my lovely...

to: the moon between millions of stars in the sky