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Solar Eclipse in Retrospect

Solar Eclipse in Retrospect

 

The two minutes and six seconds of totality I experienced were otherworldly. Time had paused and I was submerged into an ethereal reality. I had spent so much time preparing for this, and yet it passed by so quickly. As the Moon’s shadow had approached from the west, an irrational fear took hold of me and I felt as if I were supposed to resist the imminent darkness but was powerless to do so. Intellectually I knew that was false, and I soon returned to peace once totality began. It was as if a gaping hole in the sky suddenly opened, surrounded by the solar corona. Stars and planets became visible. Was I dreaming? No, this was the awe-inspiring experience of a total solar eclipse.

Here is a two-minute summary video of what I captured:

The first half is simply the eclipsed Sun. The second half is a view of the west to see the approaching shadow along with a sheet spread out in the foreground to display shadow bands in the seconds before and after totality. No video can do justice to a total solar eclipse. It’s the experience of a lifetime.

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Solar Eclipse, Part 6 of 6: How I’ll Spend My Two Minutes of Totality

Solar Eclipse, Part 6 of 6: How I’ll Spend My Two Minutes of Totality

This will be my first total solar eclipse. What I am planning on doing is not necessarily what I would recommend everyone to do. Nevertheless, perhaps these plans can inspire some ideas and spark conversation.

I’ll be in the path of totality somewhere near the Oregon-Idaho border.

Busy testing new equipment, I was caught unaware by this selfie.

The first thing to do at C2 (the second point of contact), which marks the beginning of totality, is remove your eclipse glasses. It’s safe. I will probably spend most of my time just staring at the eclipsed Sun in awe. Sticking out from behind the Moon will be the Sun’s corona and chromosphere. I’ve never seen these before.

Totality is supposed to be as dark as twilight. Some stars and planets will be visible. I will definitely take a few seconds to locate Mercury for the first time (see part 2 for where to look). I’ll have my small pair of binoculars strapped around my neck in part just to make sure I don’t miss this chance to see that elusive innermost planet. Another extra measure I’m taking is wearing an eye patch from twenty minutes before C2 until C2 in order to adapt one eye to the dark. That way, one eye will be more sensitive to dimmer stars and planets, as well as the corona. Ahoy!

At some point during totality, I’ll look around at the horizon, which is supposed to resemble a 360-degree sunset. If there are any animals in my surroundings, this would also be the time I’d take a look at them and examine their reactions to the sudden darkness.

Before you know it, it will be time to count down to C3 (the third point of contact), which marks the end of totality. I’ll want to get a nice last glimpse of the eclipsed Sun before it’s over. Be sure to put your eclipse glasses back on before the blinding brightness of the Sun re-emerges from behind the Moon.

What I won’t be doing during totality

I won’t be looking at my watch or my phone. I downloaded the Solar Eclipse Timer app ($2) that will count down aloud and tell me what to look for during the crucial moments of totality. By listening instead of looking, my eyes will be free to enjoy the event.

I won’t be taking pictures. Actually, I’m setting up my tripod with a super lens attached to a DSLR camera (see picture above) in order to take a 7-minute video. I’ll start recording a couple of minutes before totality, with the Sun in the lower left corner of the field of view (because it’s before local noon for me; otherwise, I’d want the Sun to start in the upper left corner). I’ve tested the magnification; it’s zoomed out enough that even with the Sun’s motion during those seven minutes, it will still be in view until a few minutes after totality. That way, I don’t have to touch the camera or tripod during totality. Since the camera is not a human eye, I can even remove the solar filter a little before totality begins and put it back a little after it ends.

I may sneak a peek at my air thermometer, but I don’t plan on reporting an official datum for the citizen science experiment (see part 5) during totality, just during the partial phases of the eclipse.

I hope the best for everyone attempting to view the eclipse! Clear skies!

 

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Solar Eclipse, Part 5: Temperature Drop

Solar Eclipse, Part 5: Temperature Drop

Bring a sweatshirt with you on August 21! During the eclipse, the temperature may change 1/2 or 3/4 as much as it regularly does at night, based on your location and climate. This will likely be 10-15 degrees, but it could be more.

When the Moon blocks sunlight from reaching Earth, Earth’s temperature drops. Since we want to understand this phenomenon better, NASA has invited eclipse observers around the country to take part in an experiment. In order to become a citizen scientist and participate, all you need is the free GLOBE Observer app and a thermometer.

Image of the GLOBE observer app you can download for free and contribute to science during the eclipse.

You don’t have to be in the path of totality. You don’t even need good weather. As long as you are in North America, NASA can use the cloud and air temperature data you collect. If you are committed to observing the eclipse from beginning to end, this is a productive task you can perform during the stages of partial eclipse, and I would encourage you to do so.

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Solar Eclipse, Part 4: To Scale and Not To Scale

Solar Eclipse, Part 4: To Scale and Not To Scale

To scale or not to scale, that is the question;

Whether ’tis nobler in the mind to suffer

The slings and arrows of disproportions

Or to take a ruler to that sea of troubles

And, by measuring, correctly depict them.

…                      Aye, there’s the rub.

Shakespeare aside, when you see a diagram depicting an eclipse, a caption oft accompanies it, clarifying that it’s not to scale. Why? Here’s why. Look at this diagram. This one is to scale.

This diagram of the Sun, Earth, and Moon is to scale. The night-time side of the Earth is not darkened in this diagram.

Look how much space there is between the Sun and the Earth! Can you even see the Moon? I programmed it into the plot; it’s just so small. A diagram that is to scale helps us understand the relation between the sizes of the celestial bodies and the relative distances between them. Nevertheless, it does not help us understand what is going on during an eclipse. This is one reason why we have diagrams that are not to scale.

This diagram of the Sun, Earth, and Moon is not to scale. This diagram shows the configuration of these celestial bodies during a solar eclipse.

Here we can see that the Moon is in between the Earth and the Sun, and the Moon’s shadow falls upon the Earth. This doesn’t happen every time the Moon passes between the Earth and Sun because the shadow usually flies over the North Pole or under the South Pole. During two different intervals of about 33 days each year, the Moon’s shadow could fall upon the Earth. Only during these intervals can we get eclipses (both lunar and solar).  Whether an eclipse happens depends on the Moon’s phase. Which type of solar eclipse occurs (total, annular, or partial) depends on the relative distances between the Earth, Moon, and Sun. These are constantly changing because orbits are not perfect circles but ellipses. I hope to go into further detail about this in a future post. This should at least help us understand why to scale diagrams and not to scale diagrams are both helpful, but for different reasons.

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Solar Eclipse, Part 3: Eclipse Glasses

Solar Eclipse, Part 3: Eclipse Glasses

Looking at the Sun is usually a bad idea. Over the weekend I chatted with an optometrist, and he made it clear that permanent damage can be done to your eyes even if you don’t feel any pain. Safe ways to observe the solar eclipse include making a pinhole projector or simply wearing eclipse glasses. While I haven’t found any eclipse glasses that seemed unsuitable, the American Astronomical Society recommends five manufacturers: American Paper Optics, Baader Planetarium (AstroSolar Silver/Gold film only), Rainbow Symphony, Thousand Oaks Optical, and TSE 17.

Here I am wearing sunglasses and eclipse glasses. I was testing a solar filter I had constructed for a DSLR camera using a solar filter sheet.

Eclipse glasses serve as neutral density filters that block 99.99% of light coming from anywhere. The only thing bright enough to be seen through them is the Sun. Although they are called “eclipse glasses,” you can look at the Sun through them on any day of the year. Eclipses are just the time it’s most tempting to direct your eyes toward that fiery ball. Sunglasses do not block enough light for safe direct solar viewing. We use sunglasses on a day-to-day basis because we want to see what’s around us while reducing the amount of sunlight reaching our eyes indirectly. If you experience the total eclipse, only during totality is it safe to look at the Sun without protection. Use eclipse glasses at all other times.

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Solar Eclipse, Part 2

Solar Eclipse, Part 2

Will the sky get dark enough during the eclipse for us to see other stars in the sky? During totality, yes! When the eclipse is total, the light that reaches us from the Sun is thousands of times dimmer than a partially eclipsed Sun. (This is why you should wear eclipse glasses at all moments except the brief two minutes of totality.)

Using Stellarium, I took a snapshot of what the sky will look like near the eclipsed Sun.

A snapshot with Stellarium software of what will be in the sky near the eclipsed Sun on 21 August 2017. Although the coordinates used for this snapshot are those for Weiser, Idaho, to the naked eye there will be little difference between this view and that for any other location in the path of totality.

Notice that the bright star Regulus will be very close to the eclipsed Sun. Regulus is the same star near which a conjunction between Jupiter and Venus that Stellarium gives as June 17 in the year -1 (which I assume corresponds to 2 BC because Stellarium uses a year zero) may have been the “star” the Magi followed (I plan to write more extensively about this in the future).

Both Mars and Mercury will be close to the Sun in the sky. I am especially excited at the prospect of seeing Mercury for the first time. I have tried on several occasions and have not yet succeeded. For those who observe not too close to sunset, Venus will also be in the sky, leading the Sun, about four times further from the Sun than Mars. Jupiter will be a little further away from the Sun than Venus, and in the opposite direction. From where I’ll be observing, Jupiter will still be below the horizon, but it will have risen for most observers in the US.

A more zoomed out snapshot with Stellarium software. The coordinates chosen for this one are those for Carbondale, Illinois. The brightest object in the sky during the total eclipse will be Venus. Jupiter will also be bright. Bright stars that are not pictured but will probably be in the sky, depending on your viewing location, are Sirius (southwest of Procyon), Capella (northwest of Venus), and Arcturus (north of Jupiter). Make sure you don’t confuse these with Jupiter and Venus.

During the partial phases of the eclipse, although the light from the Sun will be reduced, it will still be brighter than a Full Moon (and you should not look at it without eclipse glasses). If any other celestial object will be visible, it’ll be Venus. Venus will be west of the Sun, in the constellation Gemini. Jupiter and Sirius are the next brightest objects. Don’t spend too much time looking at the planets and stars rather than the eclipse. Knowing ahead of time what will be up there, however, will undoubtedly enhance the experience.

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