telescopes

The Five Numbers That Explain a Telescope

April 4, 2020 by Brian Ventrudo Filed Under: Astronomy Equipment

A 14" Schmidt-Cassegrain telescope (credit: Celestron). — A 14″ Schmidt-Cassegrain telescope (credit: Celestron).

Before we launch into the pros and cons of the types of telescopes available to stargazers today, let’s have a quick look at 5 key numbers that describe the operation and performance of every telescope, from the junk scopes in a department store to the venerable Hubble Space Telescope. Once you understand these 5 numbers, you will understand the similarities and differences between telescopes, and you will know how to choose the best scope for your own interests and budget [Read more…] about The Five Numbers That Explain a Telescope

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The Purpose of a Telescope

April 2, 2020 by Brian Ventrudo Filed Under: Astronomy Equipment

The 8.2-m primary mirror of Yepun, Unit Telescope 4 of ESO's Very Large Telescope, after its recoating in early March — The 8.2-m primary mirror of Yepun, Unit Telescope 4 of ESO’s Very Large Telescope, after its recoating in early March

Here we cover an essential but often overlooked point about telescopes. It may seem strange to cover this, but once you understand this point, you’ll understand the trade-offs involved in choosing a good telescope for stargazing. The fact is, most beginners believe the purpose of a telescope is to magnify objects, to make them appear bigger. This is not true. What, then, is the purpose of a telescope? [Read more…] about The Purpose of a Telescope

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How to Look Through a Telescope

December 21, 2017 by Brian Ventrudo Filed Under: Astronomy for Beginners

The art of looking through a telescope. Image credit: Brian Ventrudo

Newcomers to astronomy and casual stargazers are sometimes disappointed by their first glimpses through a telescope, especially when looking at deep-sky sights like star clusters, galaxy, and nebulae. They look through the eyepiece, see a dim smudge without much detail or any color, and conclude that one dim smudge looks like all the others. Some become disillusioned, wonder what all the fuss is about, and take up bird watching instead.

Like most activities, however, looking through a telescope takes a little skill and practice. But once you get the hang of it, you can learn to see an astonishing amount of subtle detail, even in a small telescope. The image of a distant galaxy or star cluster in your telescope will never rival the pro-quality photographs you see in books and magazines. But with a little practice, you’ll learn to observe subtle detail and structure in faint objects that even the best cameras will never capture. Here are a few tips to help you get the best view of ‘faint fuzzies’ through a telescope… [Read more…] about How to Look Through a Telescope

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Tele Vue DeLite Eyepiece Review

August 7, 2015 by Brian Ventrudo Filed Under: Astronomy Equipment

The Tele Vue DeLite line of eyepieces (credit: Bill Paolini)

Looking for an eyepiece that makes stargazing a little easier? The new Tele Vue DeLite series of eyepieces might fit the bill. These new eyepieces feature a modest 62º field of view, a far cry from the super-wide Nagler and Ethos line of eyepieces from Tele Vue, but the DeLites excel in one important feature: they’re easy to look through. Read this full review of the DeLite eyepiece line by William Paolini, author of the book Choosing and Using Astronomical Eyepieces. It’s available at the new astronomical community website called Astronomy Connect.

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World’s Biggest Telescopes

June 1, 2015 by Brian Ventrudo Filed Under: Science

Comparative sizes of the objectives of the world’s largest telescopes (completed and planned). Credit: Wikipedia

From its launch in 1948 until 1975, the largest telescope in the world was the Hale Telescope on Palomar Mountain in southern California, a giant Newtonian reflector with a mirror 200 inches (5 meters across). Even when Hale was displaced by the 6-meter Russian BTA-6 telescope, it remained the most effective large-aperture telescope in the world because the Russian behemoth suffered from many design flaws and operational problems.

But in the early 1990’s, Hale was bumped once and for all from the top of the telescope world. That’s when the first of the two Keck telescopes, each with 10-meter mirrors, became operational at an observatory on Mauna Kea. Since then, ground based astronomy has entered a new period of rapid innovation and growth as larger and more sophisticated instruments come online, most with adaptive optics and systems to combine the light from more than one mirror. The Keck scopes are still #2 on the list, and were only recently bumped by a slightly larger scope called the Gran Telescopio Canarias. If you are having trouble keeping track of the world’s largest telescopes, the infographic above will help you sort out which is which [Read more…] about World’s Biggest Telescopes

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