Choosing A Telescope 3

Catadioptric Telescopes Continued...

The Schmidt Cassegrain is the most popular type. The Maksutov is a variation with a differently shaped corrector. The 'Mak' offers excellent image quality - refractor like, although the thick corrector can cause thermal stability problems.

In the past, these have been expensive but now Meade and Russian-built versions have lowered the price greatly.

The catadioptric's drawbacks?…

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Choosing A Telescope 2

Telescope Types:

Achromatic Refractors

Achromatic refractors are those with two lens elements at the front of a tube.

They offer crisp, high contrast views due to their clear aperture; i.e. they have no central obstruction that reduces contrast.

They also have a high transmission of greater than 90%. The light travels down the sealed tube only once so the impact …

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Choosing A Telescope

Although it is possible to have many hours of pleasure observing the night sky using the naked eye or binoculars, at some point in every amateur astronomer's career the decision is made to buy a telescope.

The process of buying a telescope is a difficult one and mistakes can be expensive. Before you reach for your credit card, you really …

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Equipment for the Amateur Astronomer
Beginner's Telescopes

Binoculars and telescopes and other astronomy equipment and accessories are the meat and potatoes of amateur astronomy. A good pair of binoculars is what introduced me to the pleasures of stargazing many moons ago and only after a couple of years scanning the skies did I graduate to a telescope. That was one of the department store 60mm …

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ESA Gaia Colour Preview

While surveying the positions of over a billion stars, ESA's Gaia mission is also measuring their colour, a key diagnostic to study the physical properties of stars. A new image (above) provides a preview of Gaia's first full-colour all-sky map, which will be unleashed in its highest resolution with the next data release in 2018.

Stars come in a variety …

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Cassini Spacecraft

NASA’s Cassini mission will come to a spectacular close on September 15, 2017 at 5:07 a.m. PDT after almost two decades in space since its launch in 1997. The spacecraft has been orbiting Saturn and studying that system for 13 years. It’s now checking off items from a daring bucket list as it makes the most of its final months.…

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Saturn's Moon Titan

Saturn’s giant, hazy moon Titan has been essential to NASA’s Cassini mission during its 13 thrilling years of exploration there.

Cassini and the European Huygens probe have revealed a fascinating world of lakes and seas, great swaths of dunes, and a complex atmosphere with weather – with intriguing similarities to Earth.

Titan has also been an engine for the mission, …

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A partial solar eclipse seen from space

Thanks to a quirk of our cosmos, the Moon’s average distance from Earth is just right for it to appear as the same size in the sky as the significantly larger Sun. Once in a while the Moon slides directly between Earth and the Sun such that it appears to cover our star completely, temporarily blocking out its light and …

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Cosmic Rays

Hold out your hand for 10 seconds. A dozen electrons and muons just zipped unfelt through your palm. The ghostly particles are what scientists call "secondary cosmic rays" -- subatomic debris from collisions between molecules high in Earth's atmosphere and high-energy cosmic rays from outer space.

This daily shower, which never stops, is a sign of violent events in deep …

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Asteroid 2012 TC4 will fly past Earth in October 2017

A small asteroid flying past Earth on 12 October will provide scientists with a valuable opportunity to learn more about its orbit and composition. The campaign will exercise the international network of observatories and research organisations working on planetary defence.

Astronomers recently spotted asteroid 2012 TC4 under a collaboration between ESA and the European Southern Observatory (ESO) to locate faint …

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