astrophotography

Eclipse-Mania!

The October 8, 2014 total lunar eclipse.

The October 8, 2014 total lunar eclipse.

By Jim Haklar

I love eclipses. I mean, I really love eclipses! I love eclipses so much that two years ago, I flew to Albuquerque for the weekend to see a solar eclipse. But more about that later…

An eclipse happens when the Earth, Moon and Sun all line up. Technically, this is called syzygy (try to form that word in a game of Scrabble). A lunar eclipse happens when the earth is between the Moon and the Sun. When the Moon is between the Sun and the Earth you get a solar eclipse. Lunar eclipses happen when the Moon is full and solar eclipses occur when the Moon is new. So, why don’t we have an eclipse twice a month? Well, the Moon’s orbit is tilted by a little over five degrees. So most of the time there isn’t perfect alignment and you don’t have syzygy.

From any given location on the Earth, lunar eclipses are more frequently seen than solar eclipses. That’s because the Earth casts a bigger shadow on the Moon than the Moon does on the Earth. The shadows consist of two parts. There is a smaller, darker umbra surrounded by the lighter penumbra. If you are in a location where the Moon’s umbra passes through, you will see a total solar eclipse. Otherwise the solar eclipse will be partial (since you will be in the penumbra). For lunar eclipses, the situation is a little different. The Moon can completely or partially pass through the Earth’s umbra (resulting in a total or partial lunar eclipse) or just pass though the penumbra (called a penumbral eclipse).

Now for my Albuquerque story. Two years ago the Moon’s umbra passed directly in front of the Sun and this was visible in many cities including Albuquerque (I went to Albuquerque because of the clear weather). But since the Moon was at a point in its orbit when it was farther away from the Earth, it didn’t completely block out the Sun. Instead, an annulus or ring of light from the Sun’s disk encircled the Moon. This is called an annular solar eclipse.

On August 21, 2017 there will be the first a total solar eclipse visible from the contiguous United States in over 30 years. Information on the best places to see the eclipse is already on the Web, so start think about taking an eclipse vacation!

About the Author: Jim is an environmental engineer at the EPA’s Edison, New Jersey Environmental Center. In his 28 years with the agency he has worked in a variety of programs including Superfund, Water Management, Public Affairs, and Toxic Substances. He has been an amateur astronomer since he was a teenager, and can often be found after work in the back of the Edison facility with his telescope.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Saturn’s Moons – A Few Great Places to Visit

This image of Saturn and four of its moons was taken by the author on April 12, 2012 from EPA’s Edison, New Jersey facility. The moons are (from left to right): Titan, Dione, Tethys and Rhea.

By Jim Haklar

As an EPA employee, I’m reminded every day how fragile our environment is.  But when I take my telescope outside on a clear, calm night and point it skyward, I can see a place that may have environments that are just as special as our own.  And this place is Saturn.  You’ve heard of Saturn – the planet with the rings.  While most people think the rings are what makes Saturn unique (and they really are unique, being less than 1 mile thick but up to 175,000 miles across), to me it’s Saturn’s moons that make it a really special place.

Saturn has over 60 moons, 53 of which have names.  The names typically come from Greek mythology, and most of the moons are named after Saturn’s brothers, the Titans, and Saturn’s sisters, the Titanesses.  In mythology, these were giants who ruled before being conquered by Jupiter.

A while back I took a picture of Saturn with four of its moons: Titan, Dione, Tethys, and Rhea.

Titan is considered to be the most Earth-like world that has been discovered (it’s actually a frozen version of how Earth looked like billions of years ago).  Titan is the second largest moon in the solar system and has rivers and lakes made up of chemicals like ethane and methane.   Imagine being stuck in a “rain” storm on Titan!

Dione has a lot of craters (just like on our Moon) but it also has bright walls of ice that form canyons.   A very fine powder of ice from one of Saturn’s rings constantly rains down on Dione.

Rhea is a small (about 950 miles in diameter) , cold moon with no atmosphere that is similar to Dione. It has been described as a frozen dirty snowball!

Tethys is also small (less than 700 miles in diameter) and it is closer to Saturn than our Moon is to the Earth.  It is made up of mostly water ice with a little bit of rock.  It has two huge features; a giant crater called Odysseus and a valley called Ithaca Chasma.

Right now Saturn is visible, for most of the night, in the constellation of Virgo.  Take a few minutes and look up at the night sky, and think about all the strange environments that are waiting to be explored.

About the Author: Jim is an Environmental Engineer out of EPA’s Edison, New Jersey facility, where he manages PCB cleanups.  On clear nights he can frequently be seen with his telescope spying on our planetary neighbors.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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The Fun of Solar Imaging

This image of the Sun was taken by the author using a hydrogen alpha filter.

By Jim Haklar

A lot has been written about the benefits of solar power as a “green” source of energy.  But have you ever wondered what that source of energy actually looks like?  While we can’t look directly at the Sun without protection for our eyes, we can use special equipment to see the Sun in all its glory.

Astrophotography is one of my hobbies, and often on a clear day I’ll take my telescope and camera out at lunchtime and take pictures of the Sun.  I have special filters that allow me to see the different types of light that the Sun gives off.  One type of light is called “hydrogen alpha,” and with my hydrogen alpha filter the Sun really looks alive!  Just like all of us, the Sun goes through periods when it is more active and less active.  For the Sun, these periods come in 11- year cycles and scientists are predicting that in the current cycle the Sun will be most active next year.  But even now many solar features can be seen.

Loops of gas called prominences are present at the edge of the Sun; when prominences cross over the face of the Sun they look like ribbons and are called filaments.  Sometimes huge surface explosions called solar flares can also be seen, as well as sunspots.  The Sun is so big (over 800,000 miles across) that all of the features I’ve described are usually larger than the Earth.  Talk about solar power!

About the Author: Jim is an Environmental Engineer out of EPA’s Edison, New Jersey facility, where he manages PCB cleanups.  Over the last 27 years he has worked in a number of different programs within EPA, including Superfund, water management, and public affairs.   He has been an avid amateur astronomer for over 30 years.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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