Binoculars and the Moon

Next Saturday, September 15, the Moon will be approximately of the shape shown in this picture. Assuming that you happen to have a clear sky that evening, you should be able to view the Moon as described:

If you have access to a pair of binoculars, and, preferably, can support them by some means to hold them steady (a phototripod, perhaps), you can see the craters and the dark areas similar to what's shown here. It's surprising what a pair of binoculars can do. Galileo Galilei (15 February 1564 – 8 January 1642) would have given his eye teeth for optical performance like this when he was alive.

The most prominent of the dark areas is the round area near the upper right of the centre of this picture. It's called "Mare Criseum" - the Sea of Crises - and can be seen with the naked eye. It's an old impact area, of about 400km diameter. The dark material is thought to be ancient lava which erupted from the Moon when a fair-sized asteroid hit it a few billion years ago. From Earth, it looks slightly oval, but this a "perspective" effect. It is actually quite circular.

This picture was taken at the prime focus of a Celestron C-8 telescope (equal to a 2000mm lens at f10) at 1/200sec exposure with a Canon Rebel XT digital SLR camera.









Here's a closer view of Mare Criseum.

How far can you see?

Are you interested in the stars (I don't mean Hollywood's superficial celebreties)? Have you ever wondered how far away they are? Do you think you need a lot of fancy equipment to see anything meaningful in the sky? Well, despair not, you too can be an "astronomer", and all you need is your eyes (and a clear sky).

The picture you see here is a simulation of a section of the nighttime sky as it appears at about 11pm at this time of year (created by a planetarium program called Starry Night Pro Plus, available at http://www.imaginova.com/). Click on the picture to see it enlarged. If you step outside at around that time of night and look up straight overhead, you'll see at least the three brightest stars shown here. They are labelled Vega, Deneb, and Altair. You can draw some imaginary lines between the three to form what's known as the "Summer Triangle", most readily seen in the summer and fall months.

All three stars are a lot bigger than our own sun, and, although they appear to be of similar brightness, they are located at vastly different distances from us. Vega, the brightest, is located at a distance of about 25 light years, Altair is about 17 light years away, and Deneb can be found at a distance of about 1,500 light years.

This begs a question. What, exactly, is a light year? The first thing to realize is that it represents a distance. How is that defined? Well, a light year is the distance that light travels in one year. The speed of light has been measured very accurately, it's just about 300,000km per SECOND. This means that light can travel around the Earth (circumference 40,000km) more than 7 times per second. There are about 31.5 million seconds in a year - so the distance of one light year is 31.5 million times 300,000km; it's a tremendous stretch. You do the math.

Since Deneb is 1,500 light years away, it took light 1,500 years to cover that distance. When the light we see now left Deneb, the holy Roman empire had just about disintegrated, and we were beginning to enter what has been called a cultural wasteland: the "dark ages". Similarly, the light which left Altair and Vega has travelled for the same number of years as they are distant (measured in light years, again). It's hard to imagine that Deneb is almost 100 times farther away than Altair, yet they appear almost equally as bright from Earth. What a tremendous difference exists between individual stars. We'd be fried instantly, if Vega were located as close to us as our own sun.

You can see that when you look at the stars, you are also looking backward in time. For all we know, these stars may have exploded by now (a common occurrance for huge stars); we won't know that until 25, 17, or 1,500 years from now, respectively.

What were you doing at the time the light left the stars mentioned?

You can understand the sky without any special equipment - you can see things that are a long way off. Your eyes and an open mind are all that's required. To really appreciate the grandeur of the universe, though, you ought to find a truly dark sky - a location away from the pervasive light pollution which wipes out all the faint stars in our cities.

Classics

When the weather is nice, many people exhibit treasures which they would not want exposed to rain. One such category is that of classic cars. Beautifully maintained, they hark back to an age when driving was courteous, considerate, and far less aggressive. Some have lines that would be a wonderful fit for today's high tech wonders, others reflect the society of yore. In short, they're "classic". We thought that we should have a look at these - there is an "old car" show on in town at the moment.

My wife and I fit right in. Those years in which these beauties were manufactured were our "young" years, and I think that the pleasure of driving was far more appreciated then. We certainly had our (usually clean) fun, and were perhaps more aware then today's young folks regarding the responsibilities of being in charge of these big machines. Be that as it may, our generation is likely to be considered as "backward" as these vehicles; our internal "guts" probably work with the same degree of efficiency. We need as much or more ongoing maintenance - we're "classic", too.

Grandparents' joys

One of the joys and privileges of being grandparents is that you are allowed to spoil your grandchildren, and have fun doing it. Therefore, we took advantage of the fine weather today and invited our granddaughters Marina and Lauren to our annual, local fair, called the Pacific National Exhibition. Perhaps saying that our granddaughters intimated that an invitation would not be resisted approaches the truth even more closely.

The PNE started about a century ago as an agricultural fair, with a small amusement park (Playland) on the side. Well, Playland has become the main reason why people attend it; Marina and Lauren naturally came for the same reasons - the rides and games.

One of the cultural parts of the exhibition outside Playland was really classy - the acrobats from China were amazing. We all enjoyed that.

Of course this also became a "junk food day" - every now and then you have to forget about the restrictions you face as a senior.

As grandparents, we had a lot of fun watching the granddaughters screaming their way through the many rides they went on. It also brought back memories of our own "young" PNE days.




This was very much a fun (and exhausting) day.

Surprising interest

Over the years, I've participated in many a public astronomy night, where we we would take our telescopes and set up for public viewing. Invariably, everyone attending was impressed, sometimes awestruck, often incredulous as to the things one can see through a telescope. In my mind, the people who show up at these events always have a keen interest in astronomy, and they know it. They make the effort to come. Conversely, I thought until now that people who didn't show did not have that kind of curiosity, or didn't think of it as being important, if they had heard about the event.

Since I started my blog just a little over a month ago, I think that there are not many readers of it around. Considering that, a fair percentage of comments come back to me. To my surprise, my post about the recent lunar eclipse brought some responses which make me think that many people would like to know more about what can be seen "up there", without having any specialist knowledge in that regard.

There are some easy ways to do these things yourself - without any special equipment. Naked-eye astronomy, astronomy using binoculars, basic cameras.... one can do a lot in that regard. If there is enough interest, I can occasionally do a post about this.

The Moon hiding

This is the setup used for the eclipse pictures shown below. There was a constant, varying haze in the sky, necessitating some exprimenting with exposure times. The final phases were not captured, because solid clouds obscured the Moon in the end.


















As mentioned before, this morning a total eclipse of the Moon occurred. I woke up just in time to witness and photograph the event. The above image shows the Moon just disappearing into the Earth's shadow.


This shows the Moon when it had moved well into the Earth's shadow:




The orange tint is the result of the sunlight refracted around the Earth. As seen from the Moon, the Earth would seem to be surrounded by a "ring of fire" of this orange colour. It's like a sunset, except as seen from far away in space, with the whole Earth blocking the Sun.









The Moon is now at midpoint of the total eclipse:





Taken with a Canon Rebel XT through a Celestron C90 telescope at f11 (= a 1000mm focal length telephoto lens - see top image) and an exposure time of 3.2 seconds, sensitivity at 800 ASA.

Added on Aug 31:
You'll notice that the Moon does not appear quite sharp in one direction here. The cause is the Earth's rotation.

There is a faint image of a star streak close to the left edge of the image. The length of this streak tells you how much the image shifted due to this motion during the 3.2 seconds. If I had used my "equatorial" mount, and attached the telescope and camera to it, there would have been no "smear"; that type of mount compensates for the rotation, and is used for those astronomical photos which require many minutes or hours of exposure time.


Leaving the Earth's shadow:
f11 at 1/20 sec
















f11 at 1/160 sec

Eclipse of the Moon

On the morning of August 28, 2007, the full Moon will move through the Earth's shadow. This event is not rare, it is the second such event this year. This one, however, takes place at a time when the Moon is above the horizon for North and South America, the Pacific Ocean, and countries around the Pacific Rim. While the eclipse can be seen from beginning to end in the Pacific Ocean and the West coast of North America, the remainder of the locations mentioned above will at least see a part of it, while some of it occurs after the Moon sets (Eastern North America, all of South America), or before the Moon rises (Eastern Asia, Western Australia).

The various phenomena that occur on the Moon are seen simultaneously in all areas mentioned; the various locations have their own local time, of course. There is a worldwide standard time called Universal Time (UT), which is used to relate all world-wide phenomena and activities. For instance, the computer systems in the financial world have to be based on this time reference, in order to maintain the relationships of financial transactions. Other uses for an agreed-upon, common time reference are found in transportation and travel scheduling, this common reference is of importance to us here, in science, too - astronomy in this case. So here is the UT sequence of events for this Lunar Eclipse:

Penumbral eclipse begins (the first imperceptible darkening of the Moon) 7:53:39 UT
Partial eclipse begins (the main Earth shadow begins to cover the Moon) 8:51:16 UT
Total eclipse begins 9:52:22 UT
Greatest eclipse 10:37:22 UT
Total eclipse ends 11:22:24 UT
Partial eclipse ends 12:23:30 UT
Penumbral eclipse ends 13:21:01 UT

(all times taken from the Observers' Handbook of the Royal Astronomical Society of Canada, Toronto, Ontario, Canada)

UT is sometimes stated as Greenwich Mean Time (GMT). The various locations on Earth have their local time assigned based on their geographical "time zones". For North America, these time zones are 4 to 8 hours (East to West) "behind" UT. For instance, the Greatest eclipse for the West coast of North America, stated in Pacific Standard Time (PST) is 10:37:22 UT - 8 = 2:37:22 PST. An added complication is the use of daylight saving time. This adds an hour to the Standard Time in each time zone. So, for the above example, the Greatest eclipse occurs at 3:37:22 in the morning.

This event requires no telescope - the naked eye does a great job here. Any pair of binoculars will enhance the experience; in fact, for me, binoculars are the preferred means by which to view this event. Photography is relatively easy, but use a tripod and your optical zoom or zoom lenses to their maximum extent. The Moon appears surprisingly small in pictures taken with standard focal length lenses.

For an observer on the Moon, this event would look similar to this image of the planet Saturn, as seen from the Cassini probe - minus the rings.