Unknown Universe - Universe Still Need To Be Discovered

The Paradox Of The Great Acceleration Of Gravity On The Surface Of A Neutron Star

2018-06-08T14:25:00.000+05:30

In a neutron star with mass Mns = 1,4MS (MS = Solar mass) and radius Rns = 10 Km, the acceleration of gravity at the surface, of which comply with existing theory, is:

This means a body that performs free fall on the surface will change its speed during
ΔU = 1,85859 ∙ 10 ^ 12 m / s
at every second.
This speed but is much greater than the speed of light
C = 300000 Km / s = 3 ∙ 10 ^ 8 m / s
ΔU / C = 6000
But nothing can move with greater speed of light and here we see the weakness of the existing theory.

CALCULATION THE ACCELERATION OF GRAVITY ON THE SURFACE OF A NEUTRON STAR WITH THE USE THE NEW WORLD CONSTANT OF GRAVITY GN.

In a neutron star with mass Mns = 1,4MS and radius Rns = 10 Km, the acceleration of gravity at the surface gns, will comply with the

So that is the acceleration of gravity at the surface of the above neutron star and as shown is smaller than the Earth by 7.74 times.
Let us not forget that the Earth has as its core a neutron star with a radius of 1278 Km.

In a neutron star with mass Mns = 1,4MS and radius Rns = 10 Km, the acceleration of gravity at the surface gns, will comply with the new GN

So that is the acceleration of gravity at the surface of the above neutron star and as shown is smaller than the Earth by 7.74 times.
Let us not forget that the Earth has as its core a neutron star with a radius of 1278 Km.

So we see that the current world today gravitational constant

It can not be applied to the surface of a neutron star. So if we accept the existence of neutron stars as existent heavenly bodies according to the observations of astrophysical, then we need to look for a new global gravitational constant that applies to the entire universe.
The new universal constant of gravitation proposed here

believe that satisfies this condition.

Source : NEW COSMOS
By George Georgitzikis

The MOON core has a density similar to a Neutron Star

2018-06-07T11:08:00.002+05:30

CALCULATING THE MASS OF THE MOON WITH THE USE OF NEW

CALCULATING THE RADIUS AND VOLUME OF THE MOON BEFORE 4.6 BILLION YEARS.

CALCULATING THE EXPANSION OF THE MOON.

Accordingly, the Moon constantly expands for 4.6 billion years, the same procedure described for the Earth in a previous article, except that on the Moon, the volume rate of change per year per Kg initial neutron mass, appears to be greater than that of the Earth:

The MOON core Has a density similar to a Neutron Star

This is likely due to the lack of atmosphere on the moon resulting in faster cooling, unlike the earth, where the atmosphere acts as an insulating layer. Even thicker mantle Earth and the thicker crust together with the body of water of oceans is an additional insulating layer which slows down heat loss and cooling.

A further indication of the expansion Moon, are the dark areas of the surface, the so-called "seas", corresponding to the Earth's oceanic crust is obviously younger than the light areas of the surface.

Observing the photos below, we see that the number of craters in the dark areas of the surface is much smaller than in the light areas of the surface.

Source : NEW COSMOS

By George Georgitzikis

In The Center Of The SUN There Is a Neutron Star

2018-06-06T20:15:00.001+05:30

CALCULATION OF SOLAR MASS, CONSIDERING THE EXISTENCE OF A NEUTRON STAR IN THE CENTER.

For this calculation we will use the new constant universal gravitation GN, as calculated in the previous article.
The centrifugal force of the Earth due to the behavior around the Sun, is equal and opposite to the Sun-Earth tractive force.
Where:

This mass is also higher by 1,466940x10^12 times the current permissible mass of the Sun.

CALCULATION OF THE INITIAL VOLUME AND THE INITIAL RADIUS OF THE SUN AS A NEUTRON STAR.

If the above mass of the Sun turned into a neutron star with a density ρ =10^15 gr/cm3 , then 4.6 billion years ago the original volume of the Sun would:

This is approximately the current radius of the Sun's inner core, which retains the density of a neutron star.

CALCULATION OF CHANGES IN VOLUME OF THE SUN FROM THE DATE CREATION.

The expansion process then is similar to that of the Earth, only about rapidly in the Sun, due to the greater initial mass of the neutron star and the lack of insulating layers, which would prevent cooling.

Accordingly the Sun continually expanded for 4.6 billion years by the same procedure described for the Earth in the previous article, except that the Sun due to the greater initial mass of the neutron star, has created a liquid outer core comprising heavy metals in the inner layers and lighter non-metallic elements to the outer layers and then all of the above are surrounded by a gaseous crust mainly consisting of hydrogen and helium that is known photosphere.

Possibly in layers deeper the photosphere, occurring consecutive fusions, increasingly heavy elements until the iron level, while still deeper we found evidence even heavier, which will not now come from nuclear fusion, but by nuclear fissions super massive metals.

After a few billion years the Sun will have a structure similar to the Earth, that will create mantle and outer bark with oceans and atmosphere the composition of which will not necessarily be like the Earth.

And in this situation will remain for the next billion years as an "Old man Sun" until the next cosmic collision with another star and the creation of a supernova, where the cycle starts again from the beginning with the creation of a new solar planetary system.

Source : NEW COSMOS

By George Georgitzikis

NASA Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star

2017-02-24T13:55:00.000+05:30

NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.

The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system. All of these seven planets could have liquid water — key to life as we know it — under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

"This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life," said Thomas Zurbuchen, associate administrator of the agency's Science Mission Directorate in Washington. "Answering the question 'are we alone' is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal."

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. Assisted by several ground-based telescopes, including the European Southern Observatory's Very Large Telescope, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

The new results were published Wednesday in the journal Nature, and announced at a news briefing at NASA Headquarters in Washington.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them, allowing their density to be estimated.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces. The mass of the seventh and farthest exoplanet has not yet been estimated — scientists believe it could be an icy, "snowball-like" world, but further observations are needed.

"The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star," said Michael Gillon, lead author of the paper and the principal investigator of the TRAPPIST exoplanet survey at the University of Liege, Belgium. "It is also the best target yet for studying the atmospheres of potentially habitable, Earth-size worlds."

In contrast to our sun, the TRAPPIST-1 star - classified as an ultra-cool dwarf — is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other. If a person was standing on one of the planet's surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth's sky.

The planets may also be tidally locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong winds blowing from the day side to the night side, and extreme temperature changes.

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. In the fall of 2016, Spitzer observed TRAPPIST-1 nearly continuously for 500 hours. Spitzer is uniquely positioned in its orbit to observe enough crossing — transits — of the planets in front of the host star to reveal the complex architecture of the system. Engineers optimized Spitzer's ability to observe transiting planets during Spitzer's "warm mission," which began after the spacecraft's coolant ran out as planned after the first five years of operations.

"This is the most exciting result I have seen in the 14 years of Spitzer operations," said Sean Carey, manager of NASA's Spitzer Science Center at Caltech/IPAC in Pasadena, California. "Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets."

Following up on the Spitzer discovery, NASA's Hubble Space Telescope has initiated the screening of four of the planets, including the three inside the habitable zone. These observations aim at assessing the presence of puffy, hydrogen-dominated atmospheres, typical for gaseous worlds like Neptune, around these planets.

In May 2016, the Hubble team observed the two innermost planets, and found no evidence for such puffy atmospheres. This strengthened the case that the planets closest to the star are rocky in nature.

"The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets," said Nikole Lewis, co-leader of the Hubble study and astronomer at the Space Telescope Science Institute in Baltimore, Maryland. NASA's planet-hunting Kepler space telescope also is studying the TRAPPIST-1 system, making measurements of the star's minuscule changes in brightness due to transiting planets. Operating as the K2 mission, the spacecraft's observations will allow astronomers to refine the properties of the known planets, as well as search for additional planets in the system. The K2 observations conclude in early March and will be made available on the public archive.

Spitzer, Hubble, and Kepler will help astronomers plan for follow-up studies using NASA's upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone, and other components of a planet's atmosphere. Webb also will analyze planets' temperatures and surface pressures — key factors in assessing their habitability.

NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate. Science operations are conducted at the Spitzer Science Center, at Caltech, in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at Caltech/IPAC. Caltech manages JPL for NASA..

Credit : NASA and JPL/Caltech

Source : Hubble Site

Which Telescope Should I Buy?

2016-11-30T22:24:00.002+05:30

If you go out to any telescope store you will see many stores owner will try to sell you a small and cheap telescope by saying it has 600X magnification and it can show craters in moons, Jupiter's belt, Saturn rings, etc... not only this they will also show you the original box which has wonderful colored pictures of planets, galaxies, nebulae and much more. Beware of all these telescopes because the wonderful colored pictures that you saw in original box was all taken from Hubble Space Telescope. In real it will not look like the pictures you saw in original box. This will hurt your interest and curiosity of being a Amateur Astronomer. Due to this reason many new comers who comes to astronomy worlds get hurts and leave the wonderful astronomy world without knowing the real facts. So, always be aware not to fall into the trap of those telescope stores owners.

Before buying your first telescope keep in mind few things

1. Never buy any telescope without knowing anything about it. I suggest you to visit your nearest astronomy clubs. Look through different peoples telescopes with different eyepieces to know what eyepieces are and what they do. Discuss with them what you want to see they can help you out in getting a good telescope.

"For ex - Watching moons craters, planets, planetary details like watching Jupiter's belts, Saturn's ring or interested in Deep Space Objects (DSO's) like galaxies, nebulae, star clusters or something like this."

The best thing is that without wasting your huge money just buy a used telescope and learn something from it and plan for your future one which you really want and at best price.

2. Never buy your telescope from a toy store or from a un-reputable seller. You may get some telescope at cheaper price but their optics quality will be very very poor and this will disappoint you and nothing else. So, always select your telescope from a reputable dealer.

3. Never fall into the trap of a seller who is convincing you to buy a telescope which he is claiming to be of superior quality. Its always better to visit your nearest astronomy clubs. Look through different peoples telescopes with different eyepieces to know what eyepieces are and what they do. Discuss with them what you want to see they can help you out in getting a good telescope.

4. Always visit to reputable telescope dealer who has good knowledge about it. A good dealer will ask your requirements and he will give his best to choose a telescope you need.

All the informations mentioned above should be followed.

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Before buying any telescope you should know few important things about it. Without having proper knowledge it is foolish to buy any telescope.

Aperture

Aperture is the most most important part of any telescope. Get the bigger aperture till you can afford it. Aperture is the diameter of the mirror or lens that collects light. In simple words, just compare it with our eyes. We cant see much distant planets because they are far away and when it comes to galaxies, they the most far away objects. Our eye is unable to see them because the light coming from distant planets or galaxies is beyond our eye range. Our eyes can not collect enough light from distant objects as it is small. We need certain things that work as a bigger eye, which we call it as mirror or lens.

The bigger the diameter of mirrors or lens the more light it collects. Lens or mirrors works as a big eye and collects light from distant objects. The more light it collects the more details of that objects we can see.
Its simple!!!!

Magnification of any telescopes depends on its aperture. Large aperture collects more light and gives higher magnification and greater resolution(good quality images). So, those cheap telescopes offering high magnification will show some satisfactory view of nearer objects like Moon along with its craters, Jupiter along with its four moons, etc.... but those distant object will look fuzzy because these cheap telescopes aperture is not large enough to support high magnification and to show vivid details of that distant objects.

So, always keep in mind to go for larger aperture. Get the bigger aperture till you can afford it.

_________________________________________________________________________________________

Eyepiece

What is Pulsar?

2016-07-30T19:38:00.001+05:30

A pulsar is a highly magnetized, high speed rotating neutron star that emits a beam of electromagnetic radiation. Pulsar is a short word for pulsating radio star. Pulsars radiate two narrow beams of light in opposite directions but appear to flicker because they spin ( its similar the way a lighthouse is seen on the ocean by a observer).

From earth pulsar may look like its blinking but in reality its not. When pulsar rotates, the beam of light also rotates and during rotation the beam moves away from earth view and when it comes back again and point towards earth and makes it like its blinking. As mentioned above that its similar the way a lighthouse is seen on the ocean by a observer.

Pulsars pulses range roughly from milliseconds to seconds for an single pulsar. Most of the pulsars rotates at once per second and they are called as slow pulsars where as those pulsars rotates hundreds of times per second are known as milliseconds pulsars.

How a pulsar is formed?

The formation of a pulsar begin when the core of a massive star is compressed during a supernova, which collapses into a neutron star. it is formed with very high rotation speed. A beam of radiation is emitted along the magnetic axis of the pulsar, which spins along with the rotation of the neutron star. The magnetic axis of the pulsar determines the direction of the electromagnetic beam, with the magnetic axis not necessarily being the same as its rotational axis. The beam originates from the rotational energy of the neutron star, which generates an electrical field from the movement of the very strong magnetic field, resulting in the acceleration of protons and electrons on the star surface and the creation of an electromagnetic beam emanating from the poles of the magnetic field. This rotation slows down over time as electromagnetic power is emitted. When a pulsar's spin period slows down sufficiently, the radio pulsar mechanism is believed to turn off (the so-called "death line"). This turn-off seems to take place after about 10–100 million years, which means of all the neutron stars born in the 13.6 billion year age of the universe, around 99% no longer pulsate.

What is Nebula?

2016-07-17T16:03:00.001+05:30

Nebula is a beautiful objects in the universe which cannot be ignored when it comes to discuss about universe. What is it exactly?

In Latin word Nebula means "Cloud". It is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Nebula is not just a cloud of dust, hydrogen, helium and other ionized gases but it is also a "Stellar nurseries" i.e. the place where new stars are born. Most nebulae are of vast size, even hundreds of light years in diameter.

The Orion Nebula, the brightest nebula in the sky that occupies a region twice the diameter of the full Moon, can be viewed with the naked eye. A nebula that is barely visible to the human eye. Many nebulae are visible due to their fluorescence caused by the embedded hot stars, while others are so diffuse they can only be detected with long exposures and special filters.

Gas Pillars in the Eagle Nebula (M16) Pillars of Creation in a Star-Forming Region

Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter, and eventually will become dense enough to form stars. The remaining material is then believed to form planets and other planetary system objects.

Nemesis

2016-07-11T19:49:00.003+05:30

The Nemesis Star - Our Sun's Companion

2016-07-11T19:43:00.000+05:30

Scientists have been puzzled by an apparent cycle of mass extinctions that happen roughly every 26 million years (though some argue that it is more likely a 63 million year cycle). If the evidence holds true, and there are cycles of mass extinction on Earth, what could be the cause? Well some have suggested that there is a heavenly explanation. Specifically, our Sun might be in a binary system. And our Sun's companion -- deemed the Nemesis star -- is responsible for destroying life on Earth.

History of the Nemesis Star Theory

Analysis of the fossil record indicates that there are periods of time in history where a massive number of species, including all types of living creatures, become instinct. In 1984 researchers David Raup and Jack Sepkoski identified 12 such mass extinctions with each occurring roughly 26 million years after the previous event.
It should be noted that the accuracy of these claims has been widely challenged in the literature. At the very least, the 26 million year cycle length is often called into question, with periods closer to 63 million years often proposed. In either case, the last 25 years has seen a multitude of theories to try and explain this phenomenon.
In 1984 after the popularization of the mass extinction models two independent research groups (the first of Daniel Whitmire and Albert Jackson, and the second of Marc Davis, Piet Hut, and Richard Muller) devised theories for the cause of these mass extinctions that involved the presence of a companion star to our Sun. Essentially, each theory outlined how a star, yet to be detected, could disrupt the comets in the Oort Cloud and send them hurtling into the inner part of the solar system.
The logical question is, why is this theory any better than others that have been proposed? The main reason is that it provides a convenient explanation to observational data of the Oort cloud that scientists don't have an explanation for. Our Oort cloud has sharp, well-defined edges like those of Oort clouds around stars in other binary systems. Where as Oort clouds of isolated stars are far more diffuse. Additionally, researchers have noticed that most of the comet which make their way into the inner part of the solar system come from the same region of the Oort cloud. This indicates that there is some sort of gravitational disruption in that specific direction.
There was also recently discovered a dwarf planet, known as Sedna, that has a very unusual, and highly elliptical, orbit. At its farthest point it is nearly 1000 times further away from the Sun than the Earth is from the Sun. Scientists are baffled by its very existence, claiming that it could not possibly remain in its current orbit unless it is being influenced by another, massive object. So it would seem that even though no companion has yet been confirmed, it would seem likely given the observational data we have thus far.

What is the Nemesis Star and How Do We Find It?

There are two competing theories as to what the Nemesis star actually is. The theory put forth by Whitmire and Jackson stipulates that it is not a star at all, but rather a brown dwarf -- a protostar that never accumulates enough mass to ignite nuclear burning and become a star -- orbiting out in the Oort cloud. The typical mass of a brown dwarf is somewhere between that of a planetary gas giant (like Jupiter) and the lowest mass stars (about 8% the mass of our Sun).
Brown dwarfs are very difficult to detect since they are non-luminous -- since they do not readily radiate energy due to a lack of nuclear fusion or other exothermic reaction. Though, energy can be radiated due to their slow gravitational contraction heating the gas molecules within the object. For this reason, brown dwarfs should radiate light in the infrared.
Luckily a new infrared observatory, WISE, has been launched that should have the capability to detect such an object if it does exist. After WISE performs two complete scans of the sky researchers will be able to compile the data and map the positions and motions of all the nearby infrared objects, including Nemesis if it exists. However, it will take until at least 2013 to complete the scans and compile all the data.
But Richard Muller doesn't think that the Nemesis star is a brown dwarf at all. He and his colleagues have proposed that it is rather a small, cool star known as a red dwarf. These objects are typically much smaller than our Sun (though can be as much as half the solar mass). Muller argues that such a red dwarf is currently orbiting our Sun about 1.5 light years away (the Oort cloud extends roughly 1 light year from the Sun). But critics argue that there are problems with this theory.
If the Nemesis is a red dwarf, it would be much closer than the next closest star, Proxima Centauri (4.2 light years away). So first of all, we should have seen it already. And secondly, at 1.5 light years away it could not possibly be in a stable orbit so it could not explain the extinction cycle.
The first concern is completely valid and completely correct. We should have seen it. And actually, we may already have. There are many stars that we have observed and catalogued that we are still learning about. And given its proximity and slow proper motion, it would be difficult to determine its distance. So it may turn out that we detected the source long ago, but have only yet to realize it.
And Muller is quick to answer his critics on the second point and retort that a non-stable orbit is not a problem. In fact Nemesis has been spiraling out from our Sun for billions of years and will continue to do so. In fact, he predicts that within the next billion years or so it will no longer be bound by the Sun's gravity.

What Does This Mean For Us?

This is a question of great debate as well. There have been those that speculate that gravitational disruptions of the Oort cloud could cause comets to reign down on the inner solar system. While others believe that the Nemesis is innocuous. But we won't know for sure until we either find it or eliminate it as a possibility.

Formation of a Star

2016-07-08T18:14:00.000+05:30

Stars begin as vast clouds of dust mainly hydrogen and helium left over from the supernova and formed Nebula. A good example of such as a dust cloud is the Orion Nebula.
Far from active stars, these nebulae remain cold and monotonous for ages.

These vast clouds can be hundreds of light years across. When some disturbance overcomes this balance and causes the cloud to begin collapsing.

These disturbance may come from a shockwave from a nearby supernova explosion or a distant supernova explosion, collision with another gas cloud, or the pressure wave of a galaxy’s spiral arms passing through the region.

These force moves though the cloud, particles collide and begin to form clumps. Individually, a clump attains more mass and therefore a stronger gravitational pull, attracting even more particles from the surrounding cloud and gets compressed.

As more and more matter falls into the clump, its center grows denser and hotter. Over the course of a million years, the clump grows into a small, dense body called a protostar. It continues to draw in even more gas and grows even hotter.

When the protostar becomes hot enough 6999727ºC. Its hydrogen atoms begin to fuse, producing helium and an outflow of energy in the process.
Material continues to flow into the protostar, providing increased mass and heat.

Now, what type of star it will become depends on amount of matter present in it.

Some object does not have enough mass for stellar ignition and become brown Dwarfs.

If a star has enough material, it can generate enough pressure and temperature at its core to begin fusion "a heavier isotope of hydrogen".
If enough mass collapses into the protostar, a bipolar flow occurs. Two massive gas jets erupt from the protostar as hydrogen fusion begins and blast the remaining gas and dust clear away from its fiery surface.

At this stage newly born star stabilizes. It is the point where its output exceeds its intake. The outward pressure from hydrogen fusion now counteracts gravity's inward pull. It is now a new born star and will remain until it burns through all its fuel.

If a protostar contains the mass of our Sun, or less, it undergoes a proton-proton chain reaction to convert hydrogen to helium. But if the star has about 1.3 times the mass of the Sun, it undergoes a carbon-nitrogen-oxygen cycle to convert hydrogen to helium.

Q. What is the lifespan of newly born stars?

A. It all depends on mass and how quickly it consumes its fule i.e. Hydrogen.

Small red dwarf stars can last hundreds of billions of years, while large supergiants can consume their hydrogen within a few million years and die as supernova.

A star about the size of our sun takes roughly 50 million years to reach main sequence and maintains that level for approximately 10 billion years

This lifespan of sun began roughly 4.6 billion years ago, and will continue for about another 4.5 – 5.5 billion years, when it will deplete its supply of hydrogen, helium the elements will "swell" up, swallow Earth, and eventually die off into a small white dwarf.

What is Star ?

2016-07-08T17:57:00.000+05:30

A star is a luminous ball of plasma held together by its own gravity. The nearest star to Earth is the Sun. However, when Sun is compared with other stars in the universe it looks small dots and nothing else. In simple words Sun is very-very small when compared to other stars in the universe and known as Super Giants.

Many other stars are visible to the naked eye from Earth during the night, appearing as a fixed luminous points in the sky due to their immense distance from Earth but our Sun is close to Earth and due to this it looks very-very bright and makes DAY here at Earth. At the same time we get heat also.

Top 4 Biggest Stars In The Universe

2016-07-08T17:54:00.001+05:30

As we already know that Sun is not bigger as compared to other stars in the universe. Above image is clearly showing the comparison of stars.

So, lets see the top 4 biggest stars in the universe.

1. VY Canis Majoris

VY Canis Majoris is a red hypergiant star located in the constellation Canis Major. It is among the largest known stars in our galaxy and has a radius of approximately 1,420 solar radii (990,000,000 km; 6.6 au), and is located about 1.2 kiloparsecs (3,900 light-years) from Earth. VY Canis Majoris is a high-luminosity M star with an effective temperature of about 3,500 K.

VY Canis Majoris is surrounded by an extensive nebula, which contains condensations that were once regarded as companion stars. The nebula has been extensively studied with the aid of the Hubble Space Telescope.
It has a complex structure that includes filaments and arcs, which were caused by past eruptions.

2. VV Cephei

VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus, approximately 5,000 light years from Earth. It is both a B star and shell star.

VV Cephei is an eclipsing binary with the second longest known period. The supergiant primary, known as VV Cephei A, is currently recognised as one of the largest stars in the galaxy, with an estimated radius of 1,050 R☉.

VV Cephei experiences both primary and secondary eclipses during a 20.3 year orbit. The primary eclipses totally obscure the hot secondary star and last for nearly 18 months. Secondary eclipses are so shallow that they have not been detected photometrically since the secondary obscures such a small proportion of the large cool primary star.

VV Cephei A is fairly clearly identified as an M2 supergiant, and as such, it is given a temperature around 3,800 K. 5-8 times the radius of the Sun, 15-18 times the mass of the Sun, and around 25,000K.

3. Mu Cephei

Mu Cephei also known as Herschel's Garnet Star, is a red supergiant star in the constellation Cepheus. It appears garnet red and is located at the edge of the IC 1396 nebula. Since 1943, the spectrum of this star has served as the M2 Ia standard by which other stars are classified.

Mu Cephei is visually nearly 100,000 times brighter than the Sun, with an absolute visible magnitude of Mv = −7.6. Summing radiation at all wavelengths gives a luminosity of around 280,000 L☉. making it one of the most luminous red supergiants in the Milky Way. It is also one of the largest stars known at 1,260 R☉ (or 877,000,000 km).

The photosphere of Mu Cephei has an estimated temperature of 3,750 K. It may be surrounded by a shell extending out to a distance at least equal to 0.33 times the star's radius with a temperature of 2,055 ± 25 K. This outer shell appears to contain molecular gases such as CO, H2O, and SiO.

Mu Cephei is nearing death. It has begun to fuse helium into carbon, whereas a main sequence star fuses hydrogen into helium. When a supergiant star has converted elements in its core to iron, the core collapses to produce a supernova and the star is destroyed, leaving behind a vast gaseous cloud and a small, dense remnant. For a star as massive as Mu Cephei the remnant is likely to be a black hole. The most massive red supergiants will evolve back to blue supergiants or Wolf-Rayet stars before their cores collapse, and Mu Cephei appears to be massive enough for this to happen. A post-red supergiant will produce a type IIn or type II-b supernova, while a Wolf Rayet star will produce a type Ib or Ic supernova.

4. WOH G64

WOH G64 is a red hypergiant star in the Large Magellanic Cloud satellite galaxy in the southern constellation of Dorado. It is 168,000 light years away from Earth and is one of the largest known stars, with a radius of 1,540 solar radii, corresponding to a volume some 3.65 billion times bigger than the Sun. If placed at the center of the Solar System, the star's surface would engulf Jupiter.

WOG G64 varies regularly in brightness by over a magnitude with a primary period of around 800 days.

The Scope's Star Magnitude Limit

2016-07-07T10:04:00.001+05:30

Ok so we were supposed to be talking about your telescope so let's get back to that. We've already worked out the brightness increase we get from the scope as GL = (DO/Deye)², so all we need to do is take 2.5×log(GL) and we have the brightness increase of the scope in terms of magnitudes, so it's just Gmag = 2.5×log((DO/Deye)²).

We can take advantage of the logarithm in the equation to simplify it, by making use of the fact that log(x²) = 2×log(x). So then:

When you divide by a number you subtract its logarithm, so subtracting the log of Deye from DO , then substituting 7mm for Deye , we get:

Since log(7) is about 0.8, then 5×0.8 = 4 so our equation for the gain in star magnitude is

This represents how many more magnitudes the scope lets me see, over and above what my eye alone can see. Then to find the faintest magnitude I can see in the scope, we simply add Gmag to the faintest magnitude our eye can see, magnitude 6. This is the magnitude limit of the scope, Lmag:

Which simplifies down to our final equation for the magnitude limit Lmag of the scope

By the way did you notice through all this, that the magnitude limit of the scope — the faintest star I can see in the scope — depends only on the diameter of the objective? Interesting result, isn't it?

Aperture vs Magnitude

2016-07-07T00:44:00.000+05:30

Ever wonder how faint the objects you you can see with your telescope? Here is how you can tell, and how we derive the numbers. If you don't want to see the math, jump to the end of the article and check the tables.

The light grasp of a telescope is a function of its aperture squared. That means that a 10" telescope can see four times fainter than a 5" telescope. A 12" scope can see 9 times fainter than a 4" scope. Aperture really counts when the scope gets bigger. A 24" or 40" scope can see remarkably fainter objects than a 4" scope. The comparison is their ratios squared. For a 24" scope compared to a 4" scope, you would take 24 and divide it by 4, getting 6, and square that result to get 36.

Magnitudes are set up on a logarithmic scale. Each 5 magnitudes represent 100 times the light, each magnitude being the fifth root of 100, or about 2.51188 times. This means that a magnitude 8 star is 2.51 times brighter than a magnitude 9 star. A magnitude 12 star is 2.51 times another 2.51 times brighter than a magnitude 14 star, or about 6.3 times brighter.

Comparing magnitudes with aperture becomes a logarithm challenge. Let's start with the human eye. It has a 7mm entrance pupil and can see 6th magnitude stars. We'll use that as our starting point to calculate apertures with magnitudes. If I wanted to know what aperture optic would give me another magnitude, I'd have to calculate what the aperture would be to give me 2.51188 times the light. That means that the 7mm would increase by an amount that when squared gives me 2.51. The new aperture, A, divided by 7mm would have to be the square of 2.51. This gives us (A/7)2 = 2.51. Square rooting both sides gives us A/7 = 1.585. Multiplying both sides by 7 gives us A = 11.09mm, or 0.44 inch. If you had a 0.44" aperture telescope, it would be able to detect magnitude 7 stars.

The aperture A of a telescope divided by the diameter of the human eye's entrance pupil squared will give us the amount of light it could detect as compared to the human eye. This means that (A/7)2 = K where K is the number of times brighter the scope can see. This number K can be written as a magnitude in that M2.51188 = K. Therefore, (A/7)2 = M2.51188 where M is the magnitude difference from the human eye. Converting this to a log statement we get M = log 2.51188 (A/7)2 as being the increase of magnitude over the human eye, which is 6. So, the magnitude of the star a telescope can detect is M = 6 + log 2.51188 (A/7)2. Using the drop-down rule of logs, we can change this to M = 6 + 2log 2.51188 (A/7) . If we convert the 7 from millimeters to inches, we get M = 6 + 2log 2.51188 (A/.276). If we use the quotient rule for logs, we get M = 6 + 2log 2.51188 (A) - log 2.51188 (.076). This boils down to M = 6 + 2log 2.51188 (A) - (-)2.799, or

M = 8.8 + 2log 2.51188 (A).

Some folks don't like weird log bases, so we can fix that to either base 10 or base e. This gives us the two equations M = 8.8 +2[log 10 (A) / log 10 2.51188] and M = 8.8 + 2[ln (A) / ln 2.51188] which gives us M = 8.8 + 2[log 10 (A)/.4] and M = 8.8 + 2[ ln (A)/.921] which are

M = 8.8 + 5log 10 (A) and
M = 8.8+2.171ln(A) .

Let's try the same telescope using each formula. A 70mm scope is 10 times the aperture of the human eye, so it should give us 100 times the light grasp, which is 5 magnitudes past mag 6, so we should get magnitude 11 for an answer. Convert 70mm into inches by dividing by 25.4, that gives us 2.76 inches. In the log 10 equation we get M = 8.8 + 5log 10 (2.76) = 8.8 + 5 * 0.441 = 8.8 + 2.2 = 11.0 mag. Using the natural log equation we get M = 8.8 + 2.171* ln(2.76) = 8.8 + 2.171*1.02 = 8.8 + 2.2 = 11.0 mag. As you can see, both equations work.

If you like metrics, such as for using this equation with an 80mm refractor, then 25.4*A = D where D is the diameter of the optic in millimeters. Now we have M = 8.8 + 5log(D/25.4) = 8.8 + 5log(D) + 5log(25.4) = 8.8 + 5log(D) - 7 = M = 1.8 + 5log(D) . If you like metrics and natural logs, then it's M = 8.8 + 2.171ln(D/25.4) = 8.8 + 2.171ln(D) - 2.171ln(25.4) = 8.8 + 2.171ln(D) - 7 = M = 1.8 + 2.171ln(D) .

You don't really want to do all these calculations each time you look through a scope and want to know how deep it'll go, so here is the table:

Aperture in inches	Magnitude Limit	Light Grasp
1	8.8	13
2	10.3	52
2.4	10.7	75
3.1	11.2	126
4	11.8	210
4.25	11.9	237
5	12.2	329
6	12.6	473
8	13.3	842
10	13.7	1316
12.5	14.2	2057
16	14.8	3370
17.5	15	4032
20	15.3	5266
22	15.5	6372
24	15.7	7583
28	16	10322
30	16.1	11849
36	16.5	17063
40	16.8	21066

From the table you can determine how large of a scope you will need to observe certain objects. For example, Pluto is between mag. 14 and mag. 15. In May when it is about mag. 14.2 you can use a 12.5" scope, but later in October when it is mag. 14.7 you will need a 16" scope. Neptune is mag. 7, so you'll need a 1" scope or more (I suggest more).

There are errors in this formulation. Reflecting surfaces absorb some of the light, refracting surfaces reflect some of the light, secondary mirrors block light, glass in eyepieces take away a little, and there are others. The errors are usually in the 0.1 or 0.2 or less magnitude range, so I usually don't worry about them. The human eye can't detect light differences lower than 11%, or 0.11, which is a mag. difference of 0.1.

Juliano and I did visual magnitude tests on our scopes a few years back, and we found that we could see deeper with point source samples than this arithmetic shows. I've seen 17.1 with my 24" scope, and if the mirror had been figured a little better, I think I could have pulled more out of it, maybe as much as 0.5 more. Also, each eye is different, and each point of light has a peak frequency that it shines at, so a 13 mag. star may look like a 15 mag. star to your eye. The central star in M57 is the perfect example. Its magnitude implies that it can be seen easily, but it is very elusive.

Magnitude

2016-07-07T00:26:00.003+05:30

Q. What is Magnitude?

A. The degree of brightness of a celestial body designated on a numerical scale, on which the brightest star has magnitude −1.4 and the faintest visible star has magnitude 6, with the scale rule such that a decrease of one unit represents an increase in apparent brightness by a factor of 2.512. Also called magnitude.

The brighter an object appears, the lower the value of its magnitude, with the brightest objects reaching negative values.
The Sun has an apparent magnitude of −27, the full moon −13, the brightest planet Venus measures −5, and Sirius, the brightest visible star in the night sky, is at −1.5

There are two types of Magnitude, they are stated below just click on the appropriate link.

Apparent Magnitude
Absolute Magnitude

Power of Aperture

2016-07-07T00:21:00.003+05:30

How much you can see with a telescope has everything to do with the size of your aperture. Smaller telescopes (4 inches and under) will not reveal very much in the way of nebulas and galaxies. That being said, bear in mind that somewhere between 1750 - 1800, Charles Messier compiled a list of approximately 100 diffuse objects now known as the Messier Catalog. These objects were difficult to distinguish from comets through the telescopes of the day. So don't write off that small scope.

The chart below will give you a good approximation of the effect that aperture has relative to how much can be seen. I have used stars to demonstrate the increase in visible objects and have listed the naked eye for reference. Limiting Magnitude refers to the faintest object visible with a given size of aperture. Please bear in mind that this number is also affected by local seeing conditions, the quality of the telescope and eyepiece's optics as well as the eye of the observer. More information on magnitude can be found in the glossary.

Do Not worry about Magnitude, i will come to this topic later. Just see the chart and get to know what is written below:

Aperture inches	Aperture mm	Limiting Magnitude	Number of Visible Stars

Naked eye	Naked eye	6 (maximum)	approx 8,500
4	102	13	approx 15 million
6	152	13.5	approx 30 million
8	203	14	approx 45 million
10	254	14.5	approx 85 million
12.5	318	15	approx 130 million

Immune to Magnification

2016-07-07T00:19:00.003+05:30

Stars are so ridiculously far away that no matter how massive or blown out of proportion they may be, to us they look like points. Magnify a point, and it's still just a point.

That means that, unlike objects that cover an area, the light from a star does not get spread out as you magnify the image. All the light from the star stays inside the point.

However... as you increase magnification, the background skyglow does get spread out, which means the background gets darker and the star stays bright. This is a nice way of increasing the contrast on stars, and sometimes making fainter stars more visible.

Just remember, this works until you reach the maximum magnification of the scope, which is the same number as the diameter of the scope in millimeters. When you exceed that magnification (or the limits of the atmosphere), the stars start to spread out and dim down just like everything else.

Magnification

2016-07-07T00:14:00.004+05:30

Clearing up the myth about power (magnification).

It slices it dices it has 675 power!!!!

Over the years, magnification has been the most misleading specification printed on those glossy color boxes of many department store telescopes. Exaggerated claims of high power are almost always a sure sign of an inferior product. The real important specifications in no particular order are as follows:

Stability of the mount ... does not vibrate and moves smoothly

Size of aperture ... light gathering power

Quality of optics ... reflectivity and transmission of light

Ease of use ... point and look. The telescope needs a good finder and, in our opinion, especially for the beginner, it MUST have a reflex sighting device of some type. (see reflex sight in glossary)

Please understand, we are not saying that power is unimportant, but it should be one of the last criteria you consider.
The amount of power you can apply is dependent upon several factors such as:

Focal Length ... focal length is the distance that the light in the telescope travels from the objective lens or mirror to the point where that light reaches focus (the focal plane). To determine how much power a telescope can deliver with any eyepiece, simply divide the focal length of the telescope by the focal length of the eyepiece.

For example: If you have a telescope with a 1000mm focal length and a 20mm eyepiece, that eyepiece will deliver 50 power (1000/20). The same eyepiece in a 2000mm focal length telescope delivers 100 power (2000/20).

Focal Ratio ... telescopes are rated with an "f" number. As you look at the telescope market, the products are given specification like (6" f/5). This means the telescope has a 6" aperture and a focal ratio of 5. As with cameras, focal ratio simply represents the speed of the optics. The smaller the "f" number, the faster the optics. But how does this relate to magnification?
With any given eyepiece, fast focal ratios (f/3 to f/5) deliver lower power, wider fields of view and usually brighter images. Because of these brighter images and wider fields of views, fast focal ratios excel at deep sky observing and can deliver stunning wide-angle views. Conversely, slower focal ratios (f/6 and up) deliver higher power and increasingly narrower fields of views. Slow ratios excel at observing the moon, the planets and binary stars.

Types Of Telescopes

2016-07-06T23:05:00.000+05:30

There are three main optical types:

The refracting telescope which uses lenses to form an image.
The reflecting telescope which uses an arrangement of mirrors to form an image.
The catadioptric telescope which uses mirrors combined with lenses to form an image.

There is also different types of telescope like:

    Radio telescopes
    X-ray telescopes
    Gamma-ray telescopes
    High-energy particle telescopes

Those telescope mentioned above are used for studying different types of rays present in the universe. We dont use them for our satisfying purposes, only scientist present in NASA uses it.

So, by now you came to know that which telescope we generally use, but still i would like to mention them are:

    The refracting telescope
    The reflecting telescope
    The catadioptric telescope

Catadioptric Telescope

2016-07-06T20:39:00.003+05:30

Catadioptric or compound telescopes use both lenses and mirrors. The most popular design is the Schmidt-Cassegrain, which burst onto the market in the 1970s and quickly gained a place for itself alongside refractors and reflectors, which had been around for centuries. The following comments apply primarily to Schmidt-Cassegrains.

Advantages

The pluses of the "Schmidt-Cass" are in portability, convenience, and special options such as advanced tracking and electronics -- not visual performance. While most people can haul an 8" reflector in and out of doors, it is awkward and heavy. Most 8" Schmidt-Cassegrains come in a padded footlocker that can be hoisted with one hand. (The tripod is separate.) The footlocker can be stowed in a car trunk or closet like a large piece of luggage, whereas a reflector tends to displace everything around it.
A Schmidt-Cassegrain's relatively short tube allows a motorized mounting to track the stars more reliably, making astronomical photography less difficult (it's never easy). These are excellent photographic telescopes. Elaborate electronic drive controls are available as options on Schmidt-Cass mountings for photographers and CCD camera users. Some can be bought with robotic computerized pointing capabilities.

Disadvantages

The image formed by a Schmidt-Cassegrain will probably be a touch less sharp than the image formed by a good reflector of the same aperture. This is most noticeable when observing planets. The cost is higher than for a reflector of the same aperture. A right-angle mirror (star diagonal) is generally used at the eyepiece to provide a comfortable viewing position, and this means your view is mirror-reversed. The focusing mechanism can be a bit sloppy and imprecise. You can't take the scope apart yourself; major adjustments mean shipping it back to the factory.

Catadioptric telescopes are essentially a combination of a refractor and a reflector. There are 2 very popular flavors widely available in today's telescope marketplace. One is the Schmidt-Cassegrain, and the other is the Maksutov-Cassegrain (see images below). These telescopes fold the light path 3 times allowing for a much shorter tube. Because of their clever use of corrective lenses and lack of a spider to hold the secondary mirror, they are free of many of the optical defects present in refractors and reflectors.
Light enters the front of the tube through a corrective lens. The light then travels down the tube to the primary mirror. From there, it is reflected up the tube to a secondary mirror which in turn reflects the light back down the tube to the focal plane.

The focusing mechanisms of Catadioptric telescopes are different than in reflectors and refractors. Instead of moving the eyepiece in and out of the focal plane, the whole primary mirror is moved in and out. Because of their more complex design, their tube construction and mount are generally very well thought out and implemented. Most of them are wonderful telescopes.

Catadioptric telescopes can be very expensive, but a well-built Catadioptric telescope is quite simply a joy to own and use.

Refracting Telescope

2016-07-06T20:21:00.004+05:30

Refractor Telescopes

The refractor telescope uses a lens to gather and focus light. The first telescopes built were refractors. The small telescopes sold in department stores are refractors, as well as, those used for rifle scopes.

Advantages

Refractor telescopes are rugged. After the initial alignment, their optical system is more resistant to misalignment than the reflector telescopes.
The glass surface inside the tube is sealed from the atmosphere so it rarely needs cleaning.
Since the tube is closed off from the outside, air currents and effects due to changing temperatures are eliminated. This means that the images are steadier and sharper than those from a reflector telescope of the same size.

Though excellent refractors are still made, the disadvantages of the refractor telescope have blocked the construction of very large refractors for use in astronomical research.

Disadvantages

All refractors suffer from an effect called chromatic aberration (``color deviation or distortion'') that produces a rainbow of colors around the image. Because of the wave nature of light, the longer wavelength light (redder colors) is bent less than the shorter wavelength light (bluer colors) as it passes through the lens. This is used in prisms to produce pretty rainbows, but can it ruin an image!

There a couple of ways to reduce chromatic aberration. One way uses multiple compensating lenses to counteract chromatic aberration. The other way uses a very long objective focal length(distance between the focus and the objective) to minimize the effect. This is why the early refracting telescopes were made very long.

There a couple of ways to reduce chromatic aberration. One way uses multiple compensating lenses to counteract chromatic aberration. The other way uses a very long objective focal length(distance between the focus and the objective) to minimize the effect. This is why the early refracting telescopes were made very long.
How well the light passes through the lens varies with the wavelength of the light. Ultraviolet light does not pass through the lens at all.
How well the light passes through decreases as the thickness of the lens increases.
It is difficult to make a glass lens with no imperfections inside the lens and with a perfect curvature on both sides of the lens.
The objective lens can be supported only at the ends. The glass lens will sag under its own weight.

Reflecting Telescope

2016-07-06T18:49:00.003+05:30

Reflector Telescopes

The reflector telescope uses a mirror to gather and focus light. All celestial objects (including those in our solar system) are so far away that all of the light rays coming from them reach the Earth as parallel rays. Because the light rays are parallel to each other, the reflector telescope's mirror has a parabolic shape. The parabolic-shaped mirror focusses the parallel lights rays to a single point. All modern research telescopes and large amateur ones are of the reflector type because of its advantages over the refractor telescope.

Advantages

Reflector telescopes do not suffer from chromatic aberration because all wavelengths will reflect off the mirror in the same way.
Support for the objective mirror is all along the back side so they can be made very BIG!
Reflector telescopes are cheaper to make than refractors of the same size.
Because light is reflecting off the objective, rather than passing through it, only one side of the reflector telescope's objective needs to be perfect

Alas! Despite the advantages of the reflector telescope, astronomers must contend with some minor annoyances.

Disadvantages

It is easy to get the optics out of alignment.

A reflector telescope's tube is open to the outside and the optics need frequent cleaning.

Often a secondary mirror is used to redirect the light into a more convenient viewing spot. The secondary mirror and its supports can produce diffraction effects: bright objects have spikes (the ``christmas star effect'').

Summary of Telescope

2016-07-06T15:52:00.000+05:30

What exactly is a telescope?

The simplest definition is; an instrument that gathers light and focuses that light into an image. In turn, this image can be magnified. This instrument is also mounted in such a way that allows you to swing it from object to object. Let's break this down further.

A telescope's ability to gather light is dependent on:

Aperture ... the larger the primary optics (the largest lens or mirror) the more light is captured.

Optical quality ... the more reflective a mirror and the more a lens allows light to pass through it, the more light is transmitted to your eye.

Contrast ... the more absorptive the inside surface of the tube is, the less light will bounce around in that tube, which leads to improved contrast (darker backgrounds). A darker background means that you see more of the object you are looking at. An improperly designed optical assembly can also rob you of contrast.

Collimation (alignment) ... even if you have the best optics, if they are not properly aligned, your light gathering capacity will be diminished.

A telescope's ability to focus properly is dependent on:

Collimation ... how well the optics are aligned.

Optical quality of the eyepieces

Focusing mechanism ... a focuser that is smooth and allows for minute adjustments is necessary. This focuser must also be aligned properly to perform at its best.

A telescope's mount needs at a minimum the following characteristics:

Stability ... the telescope should not sway or bounce on the mount.

Rigidity ... when you move or focus the telescope, the stand should be solid enough to quickly dampen out any vibrations, otherwise these vibrations will be seen in the eyepiece. A poorly designed mount or a mount that is too small to handle the weight and size of a telescope can render even the best telescope useless.

Smooth motions ... the mount should move smoothly from object to object.

Telescope types and how they work

The Refractor

The refractor telescope has been around for centuries. In 1610, Galileo used a small refractor to watch the phases of Venus and observe craters on the moon. With it he discovered the first 4 moons of Jupiter and observed Saturn's odd shape. Galileo's telescope had a 2" aperture, quite small by today's standards, and was, shall we say, optically challenged. Because of this lack in optical quality, he could not resolve that Saturn's strange shape was actually caused by its rings. Approximately 50 years later, improvements in optical quality allowed observers to determine that Saturn's odd shape was actually a big ring (rings) around the planet.

To refract means to bend. Light enters through the lens at the front of the tube. This lens is called the objective. The light is refracted down the length of the tube where it eventually reaches its focal plane ( where the light becomes focused at a specific point). There, an eyepiece mounted in a focuser, allows that light to be magnified into an observable image. Simply put, the better the quality and alignment of the optics, the better the image produced by a refractor will be. Actually, this statement holds true for all telescopes.

Refractors are a very versatile instrument. With the right eyepieces, they can be used for both daytime and nighttime observing and given good optics, deliver superb detail. Small ones are also very portable. Unfortunately, high quality refractors tend to be very pricey due to the cost associated with producing high quality optics. One of the downfalls of inexpensive refractors is that for astronomical viewing, they have the tendency to add false color to images. This is called chromatic aberration. These colors usually take the form of a pale violet halo around the observed object. Don't let this scare you off though. There are many excellent entry level refractors that will perform beautifully. Many observers swear by their refractors and believe them to be unrivaled for sharp lunar, planetary and binary star observing.

The Newtonian Reflector

The reflector is a telescope design invented by Isaac Newton in the 1660s. Rather than lenses, the reflector uses 2 mirrors to bring light to the eyepiece. Light travels down the tube to the primary mirror, which is the larger of the 2 mirrors. The primary mirror is generally a paraboloid (concave) mirror. It reflects the light back up the tube to the secondary mirror. The secondary mirror is an ellipse with a flat surface which is mounted at a 45 degree angle on a device usually called a spider. The light is reflected from the secondary mirror to the eyepiece where it can be magnified into an observable image.

Dollar for dollar, reflectors offer the most aperture. They produce sharp images that are free of any added color. Optically speaking however, they have 2 things going against them:

1) The spider holding the secondary mirror forms a central obstruction that produces a diffraction pattern. This is most noticeable at high magnifications on bright objects. Look at the image below. Notice the 4 spikes coming away from the bright star in the center? This is the diffraction pattern caused by a 4-vane spider.

2) Because of the shape of the primary mirror, reflectors suffer from a condition called coma. This has the effect of making objects at the outside edge of the field of view to have the appearance of being wedge shaped or look like little comets. This really is not that big a concern for visual observation as the effect is most noticeable only at the outside most part of the field of view and not present at all in the central field of view which is where most of your observing is done anyway. Also, some eyepiece designs work well to counteract this effect.

Again don't let these characteristics scare you away from a reflector. Consider this, many big telescopes in observatories around the world are reflectors.

While there is no such thing as a perfect telescope, for visual observing a well designed 6" f/5 to f/7 reflector with good mirrors that are kept in alignment (collimated) on a Dobsonian mount (see mounts section bellow) is, in our opinion, a superb instrument that will give you years of use and not break the bank. It will deliver good views of the moon and planets and has enough light gathering power to reveal many deep sky objects given dark skies and good seeing.
Catadioptric telescopes are essentially a combination of a refractor and a reflector. There are 2 very popular flavors widely available in today's telescope marketplace. One is the Schmidt-Cassegrain, and the other is the Maksutov-Cassegrain (see images below). These telescopes fold the light path 3 times allowing for a much shorter tube. Because of their clever use of corrective lenses and lack of a spider to hold the secondary mirror, they are free of many of the optical defects present in refractors and reflectors.

Catadioptric Telescopes

Light enters the front of the tube through a corrective lens. The light then travels down the tube to the primary mirror. From there, it is reflected up the tube to a secondary mirror which in turn reflects the light back down the tube to the focal plane.

Catadioptric telescopes can be very expensive, but a well-built Catadioptric telescope is quite simply a joy to own and use.

What is Telescope?

2016-07-05T21:31:00.002+05:30

A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light). The first known practical telescopes were invented in the Netherlands at the beginning of the 17th century, using glass lenses. They found use in terrestrial applications and astronomy.

A telescope is an optical instrument comprised of a series of mirrors or lenses in order to gather more light, with a higher resolution and magnification than the naked eye. It's used to see distant objects from animals and landscape, to search space, planets, moons. Galileo used it very extensively. It primarily used by astronomers to seek out new planets, new stars, research the sun. For laymen it's a hobby to see beyond their normal vision. The simplest type is just 2 pieces of glass/plastic at the ends of a tube.