Brian Ventrudo

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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Secrets of Nightscape Imaging – Interview with Alan Dyer

May 28, 2015 by Brian Ventrudo Filed Under: Astronomy Images and Video

Nightscape of stargazers and the Milky Way through Scorpius and Sagittarius at the Texas Star Party in 2015 (by Alan Dyer)

I had the great pleasure of recently interviewing the master astrophotographer Alan Dyer of AmazingSky.com to discuss the basics of nightscape imaging with a digital camera. This sort of imaging, which combines elements of landscape photography and astrophotography, has become extremely popular over the last few years thanks to the advent of large, low-noise sensors in digital SLR cameras. Alan is the author most recently of the multi-media guide called Nightscapes and Timelapses which gives a comprehensive introduction to the art and craft of nightscape imaging.

As you listen to my interview with Alan, you will discover: [Read more…] about Secrets of Nightscape Imaging – Interview with Alan Dyer

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The Owl Nebula

May 28, 2015 by Brian Ventrudo Filed Under: Deep Sky

Northern stargazers in spring look out of the plane of the Milky Way in the night sky before midnight, so there are few bright stars and star clusters visible, and even fewer bright nebula. But there is a little gem under the bowl of the Big Dipper, the famous Owl Nebula, also known as M97. A young planetary nebula, M97 is a speeding cloud of glowing gas ejected by a small dying star. In a small telescope under dark sky, the nebula resembles the eyes of wise old barn owl gazing out of the interstellar darkness [Read more…] about The Owl Nebula

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Saturn at Opposition 2015

May 20, 2015 by Brian Ventrudo Filed Under: Solar System

Saturn at the 2014 opposition as imaged by Damian Peach (damianpeach.com)

The planet Saturn reaches opposition on May 22, 2015. It rises as the Sun sets and makes its closest approach to Earth this year. The planet is as bright as it’s been in eight years, with rings dramatically tilted towards our point of view. This is your best chance in many years to see this beautiful planet in a telescope and share a view of it with others.

Saturn lies well south of the celestial equator this observing season near the border between the constellations Libra and Scorpius in the southeastern sky (as seen from the northern hemisphere) and the eastern sky (as seen from the southern hemisphere). At magnitude 0.0 in late May and early June, Saturn is the brightest object in that part of the sky. It outshines even the brilliant red-orange star Antares to the east. By 10 p.m., you can see the planet low over the horizon, nestled near the three bright stars in the head of Scorpius. You can watch the planet’s motion relative to these stars from night to night over the next few months. It’s been moving ‘in retrograde’ a little westward each day, over and above its daily westward motion. It resumes its normal eastward motion relative to the background stars on August 2 [Read more…] about Saturn at Opposition 2015

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From the Observer’s Log: Four Great Globs

May 19, 2015 by Brian Ventrudo Filed Under: Deep Sky

Four globular clusters visible in the May sky as imaged with a Mallincam Xtreme camera, 30 s exposure, through a VRC-6 telescope.

While it may take a little practise to see the subtle differences in each of these balls of ancient stars, and despite claims of many beginning stargazers, all globular clusters do not look the same. The images above show four of the brightest globular clusters visible in a telescope this time of year. Each has a distinctive appearance, pattern, and brightness gradient. All images were taken with the same exposure and filter and with the same 6″ RC telescope so you can get an idea of their comparative appearance [Read more…] about From the Observer’s Log: Four Great Globs

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