FirstLight Astronomy Club

33°29.6'N / 117°06.8'W / 1190 ft.

Mercury Transit Authority

To be sure, there are extremely important events transpiring around the globe; problems in North Korea, the Middle East, and the Persian Gulf, politics, world hunger, and so on and so on.

So, on the Importance Scale, next week's cosmic event is probably not in anyone's Top Ten. But it is one of those rare phenomena that bears considering. And it is kinda cool.

Next week, on Wednesday the 8th, Mercury will perform a celestial feat that won't be duplicated until 2016. It will cross in front of the Sun in something astronomers call a "transit." And we on the West Coast can see the whole thing! Yay for us!

As you know, Mercury is a tiny planet that hugs the Sun at less than half the distance we are. And just as the laws of planetary motion predict, our little neighbor speeds around the Sun in a fraction of the time we do - a mere 3 months. That is mercurial to say the least.

Now if it moves that quickly, and if it is between the sun and us, this "transit" thing should happen all the time, correct? Not necessarily. Poor Mercury's orbit isn't exactly lined up with ours. Its "orbital plane" has been knocked out of alignment with most of the rest of the planets, so it is most often above or below the Sun as it passes between.

But next Wednesday, from about 11 AM to about 4 in the afternoon, it is lined up just right for us to see its dismal, pathetic attempt to eclipse the enormous Sun.

Only those of us living on the West Coast - or someone stranded in the Pacific between the mainland and Hawaii - will be able to see the whole show.
But of course we can't go out and just start staring at the Sun in hopes of seeing a tiny, almost imperceptible dot cross in front of it. You must use some sort of instrument to help you.

One can use the traditional binocular-and-a-piece-of-cardboard trick (for details see: Or you can purchase solar filters for your scope, making sure, of course, that the filters are the type that are placed in front of your scope. Filters put on the eyepiece alone pretty much guarantee a small fire and the soon purchase of a white cane with a red tip.

These filters are available online or locally at Oceanside Photo and Telescope, and can be used even after the transit to see sunspots as we head towards higher solar activity in the next several years.

But, you may say, I have no binoculars, or scope, or money for filters! Well, alrighty then, there is another option. You can contact your local astronomy club and ask them to set up something. And the very same Oceanside Photo and Telescope will have telescopes set up all day Wednesday in front of the store - weather permitting - so you can see the transit for yourself.

So, bottom line, there are no excuses for missing this rare event!

In the next weeks after the transit, as a follow-up, you might try to spot Mercury in the predawn skies starring in its next role as Morning Star.

One more bit of trivia. What is the only other planet allowed to transit the Sun? Why, it's Venus of course. A planet has to be on an inside lane around the Sun to try and come between the sun and us. Only Mercury and Venus fill that requirement. But alas! Venus won't be crossing that great ball of fire until 2012. So make the most of next Wednesday's transit!

Until next time, clear skies!

The Eyes Have It!

We have been blessed with senses. Those senses - the main of which are sight, hearing, touch, smell, and taste - bring information from the outside physical world into our other-wordly mind. We then process this information to both "make sense" of our surroundings, and to try to solve the great mysteries of the world we live in.

But what about our attempts to decipher the entire rest of the universe? What about everything beyond our tiny home? What senses do we use then to make sense of it all?

How have we discovered so much about the workings of the cosmos, from the birth of the universe to the deaths of distant blue giants, from the great superclusters of galaxies to local volcanic activity on Io?

We cannot reach out and touch the very first stars, we cannot hear the explosion of that hypernova. We cannot taste the frozen surface of Europa, nor can we smell the great red giant star in Orion, Betelgeuse, the Armpit of the Giant. I'm not sure I'd even want to.

So what sense are we left with? Sight, of course. We can see the great starry night sky assuming we live in an area not polluted with light. But our eyes are small and insensitive. Their openings, those black dots in the irises called pupils, are just millimeters across. And the back of the eye, which absorbs the light, only processes about one percent of what hits it.

This is more than enough for everyday life, but miserable for studying the universe beyond our night sky.

Moreover, our eyes are sensitive only to certain wavelengths of light, those that make up what is called the "visible spectrum," the colors of the rainbow. There is an entire spectrum of wavelengths, on both sides of the visible patch, full of information that our eyes cannot descry.

What to do?!

Enter the telescope. This profoundly important tool has changed the study of the heavens in ways indescribable.

The telescope is essentially an extension for our eye; an upgrade for those of us who want to see the whole universe. You probably have seen the standard optical telescope. It nothing much more than a "light bucket." It gathers immensely more light than our puny peepers can, and focuses it into the back of our eye so we can see those very distant, very dim objects.

Look at the modern scopes all over the world. They have light-gathering mirrors in them meters across. And if you observe closely you'll notice no one looking through any eyepieces. That's because they are all fitted now with special devices called CCD cameras which can capture not the wimpy 1% of the light our eye gets, but nearly 100% of it. "Really big, very sensitive eye extenders" you might call the modern scopes.

OK, so we learn about the universe by seeing it. And we see way better with telescopes. What about all those other wavelengths, the ones we cannot see? How can we capture and "see" them.

We devise other telescopes to "tune into" those elusive wavelengths! For example, we have gamma ray scopes to gather that wavelength, then translate the info into the visible so we can "see" the gamma activity up there.

There are also X-ray and ultraviolet scopes to complement that stronger and more dangerous part of the spectrum.

On the weaker side of the spectrum, we have infrared and radio telescopes. You may have seen the radio telescopes; they look like giant dishes.

Because of the nature of radio wavelengths - they are really long - the laws of physics demand that the dishes be huge to gather those photons into a proper focus. For us to see radio waves ourselves, our eyes would have to be enormous, way too big to get through the door.

All these "eyes on the skies" tell us how objects in the heavens are born, live, and die, what they are made of, where they are going, how they are changing over time, how hot or cold they are, and so on, and so on.

Listen carefully the next time there is a big discovery in the cosmos. Try and hear exactly what kind of scope was "looking" into the heavens, using its eyes and sense of sight to help us better understand this wondrous universe of ours.

Horsing Around in Pegasus

Answer: This horse rides around all night long, upside down, with only two front legs and no backside, but with one bright and shiny belly button.

Question: Who is Pegasus?

Correct! In the northeastern skies at this time of the year rides the great constellation of Pegasus. Our equine friend is easy to spot. Its body, what there is of it, is that giant square in the sky, called, for obvious reasons, the Great Square of Pegasus.

Pegasus was the famous winged horse from Greek mythology born, as are most winged horses, from the blood of Medusa's head with just a couple tablespoons of sea foam tossed in. The famed horse's exploits are numerous and, unique to most characters of ancient mythology, relatively free of wrongdoing. On the contrary, it appears that most everyone got along with Pegasus and had nothing really bad to say about our benevolent beast of burden.

The whole of the constellation Pegasus consists of only the front of his body. The entire hindquarters are missing. And he is upside down. But let’s focus our attention now on the most obvious characteristic about the constellation, which is, as I mentioned above, the big fat square of stars. You cannot miss it. It is in the eastern skies in the evening now and there are essentially no stars in the middle of the square, so it stands out like a sore thumb - a gigantic, squarish sort of sore thumb.

Of course, other cultures saw different things in that cosmic quadrangle. The Hindus see the Great Square as a lunar mansion, a nakshatra, one of 27 resting places for the Moon as it travels through the skies.

According to Julius Staal is his book "The New Patterns in the Night Sky," the Arawak Indians of Guiana in South America saw the great pattern as a monstrous barbeque grill!

Let's take a closer look at those four stars in our horse's body. In the southwest corner of the Square, farthest to the "right" as it rises in the evening, is Markab. Though just a pinprick in the sky, it is one energetic star. Weighing in at almost 6 suns, it outshines our own star by nearly 200 times. This is a star best seen at a distance.

The "top" star of the Square is Scheat, an old dying red giant of a star nearly 200 light years away, but nearly 200 times bigger than our sun.

At the bottom is the star Algenib, a named derived from the Arabic al janah, "the wing." It marks - you'll never guess – a wing of Pegasus. This is one bad star. It is over three times hotter than our sun (that's really, really hot in Starville) and pours out more energy than 2500 suns! Thankfully it's over 300 light years away. We can all sleep better because of that.

The last star of the Great Square of Pegasus leads a duel life. It is known by some as Sirrah, from the Arabic, Al Surrat al Faras, "the Navel of the Horse." Honestly, I didn't know horses had belly buttons. Now that I think about it, I guess they have to.

But it also known as Alpheratz, and with that name belongs officially to the constellation of Andromeda. How can that be? A corner of the Great Square of Pegasus is actually in Andromeda? It appears that Princess Andromeda needed a head, of all things, so the star's main role today is to be a melon for her royal highness. So speaks modern astronomy. Sorry Pegasus!

Sometime in this next week go out to the starfields and take a look at our equine friend, what there is of him. Then consider yourself one constellation closer to fully knowing the night sky.
Temecula Valley High School / Temecula, CA · Some images © Gemini Observatory/AURA Contact Me