Sep 10

What’s Up in the Sky

What’s Up in the Sky – September, 2020

Astronomy as an Art Form

There’s way more to astronomy than just “what’s up in the sky”. Sometimes the intersection of several branches of science or the combination of science and art can lead to some fascinating discoveries or the confirmation of existing theories.

Such is the case with the Dutch artist Johannes Vermeer’s 1696 masterpiece, View of Delft, the painting that has been hailed as Vermeer’s greatest work. Vincent van Gogh described it as “incredible”. French writer Marcel Proust thought it was “the most beautiful painting in the world”.

However, there has never been total agreement about the actual date the work was created. The appearance of the trees and boats and the various lighting effects created on the canvas led to all sorts of conclusions regarding the date and time of day depicted.

A recent article by Donald W. Olson and others in the September issue of Sky and Telescope magazine describes how astronomers answered the question of when the piece was actually painted. According to the authors, “The dark town wall and entrance gates make a dramatic contrast with brilliant sunlight that illuminates Delft’s tiled roofs and the tower of the Nieuwe Kerk (New Church).” This octagonal tower was crucial in determining the time of the painting.

First, the exact direction of the main face of the tower (which is still standing) was determined using Google Earth. Simple geometry then determines the orientation of all eight faces of the octagonal tower. The apparent size of the tower in the painting is another critical factor so the authors actually travelled to Delft and used their tape measures to find out for themselves.

Knowing the exact orientation and dimensions of the tower, the team was able to narrow down the date of the painting to two possibilities, one in April and one in September. The dates were based on the pattern of sunlight on the many facets and architectural features of the tower. Knowing the dimension and orientation of each detail, they were able to determine the exact location of the Sun in the sky. Factoring in the time of day from the image of a clock face in the painting enabled them to determine the two possible dates. Because the painting depicts trees in full foliage, the April date was rejected and it was determined that the piece was done at 8 a.m. on a date near September 3.

The exact year took a little more detective work. In 1660, a clock and bells were installed in the octagonal tower, but these are not shown in Vermeer’s painting. Therefore, the date of the work is thought to be September 3, 1659.

I found this to be a fascinating example of how our endeavors here on Earth are intrinsically linked to what’s up in the sky.

This month in history:
Sept 1 Pioneer 11 is first spacecraft to fly past Saturn – 1979
Sept 3 Last two Apollo Moon landings canceled by NASA – 1970
Sept 8 Voyager 1 launched – 1977
Sept 10 Surveyor 5 lands on Moon – 1967
Sept 23 Premier of “The Jetsons” – 1962
Sept 25 59 – day Skylab 3 mission ends – 1973

Aug 02

What’s Up in the Sky

What’s Up in the Sky – August, 2020

Even Minor Observations are Important

As I often do when starting a column, I reviewed the last four years of the “This Month in History” section at the end of each article. In doing so this month I noticed that in three out of the last four years, that section of the column included an entry about the “first televised liftoff of lunar module” and I thought, “Oh, really?” Liftoff from where? and weren’t Apollo 11 through 14 “televised”? And, wait – ah-h LUNAR module, that’s the thing Neil Armstrong referred to when he “step(ped) off the LEM now”. So, wait a minute, don’t you have to have a camera outside the spacecraft to televise its launch from the lunar surface?

The answer is, “yes”. but not only that, you have to be able to control that camera from the ground – as in Earth. No big deal, right? Wrong! You see, the problem is that when you video the launch of a spacecraft, you want to follow it along as it climbs further and further in the sky, so you have to be able to tilt the camera just right in order to follow the trajectory of your subject. Photographers call that “panning”. So now you not only have to “pan” the camera just right so it follows the LEM’s ascent, but you also have to compensate for the time delay between when your commands were sent and when they were received.

The first two attempts to track the departing spacecraft used a preprogrammed tilting mechanism to follow the ship’s progress, but it failed completely on Apollo 15 and was parked too close to the departing ship to follow it accurately on Apollo 16.

Bring in Ed Fendell, NASA scientist and imaging specialist. He manually sent the commands to the camera on the Moon three seconds early to compensate for the delay and the move worked perfectly. If you watch it on YouTube, keep in mind the effort involved in predicting and following the ship’s path and consider the fact that, no matter how minor or unimportant a particular event seemed to be, dedicated individuals give it their best shot and sometimes it turns out really well.

You can give observing your best shot this month, and chances are your efforts will be rewarded. There are great things to see in all directions, even with Comet NEOWISE now on its way out.

Start on the southern horizon and locate Sagittarius (look for the “Teapot”) and Scorpius. To the left (east) of the Teapot you will notice two very bright objects, the planets Jupiter, right, and Saturn, left. Explore these worlds with anything from a small telescope to sophisticated imaging technology.

Next, look overhead and see the Summer Triangle. Look it up before you venture out and see if you can pick out Vega, Deneb, and Altair and name their constellations. If you are in a dark location, see if you can imagine the Swan and the Eagle flying along the celestial river called the Milky Way.

Now face due north and enjoy the sight of both the Big and Little Dippers. Find Polaris, the North Star. Look down toward the NE horizon and find the W-shaped constellation, Cassiopeia.
This is what I consider to be the start of observing season – pretty good weather, time available, and great things to see up in the sky.

This month in history:
August 1: Production of Saturn V rocket ends – 1968
August 2: First televised liftoff of lunar module – Apollo 15’s “Falcon” – 1971
August 3: First in-flight space shuttle repair – 2005
August 6: Curiosity rover lands on Mars – 2012
August 18: Helium discovered in the Sun – 1868
August 25: Spitzer Space Telescope launched – 2003
August 28: William Herschel discovers Enceladus, a moon of Saturn – 1789

Jun 01

What’s Up in the Sky

What’s Up in the Sky – June, 2020

Spaceships, Galaxies, and Planets, Oh My

A newspaper column with a name like What’s Up in the Sky probably should be about things that are visible when you go outside and look up. Of course, loyal followers of the column know that its topics often include famous people, places, and events related to the science and history of astronomy. These topics usually appear when the sky offers less than memorable views or when the fun stuff can only be seen an hour or two before sunrise. So today I offer a potpourri of unrelated topics in an attempt to expand my readership.

I am old enough to remember the days of Sputnik, John Glen, and Apollo 13. After the last two Moon landings were cancelled we saw leftover Saturn rocket parts become SkyLab and watched astronauts cavort around the spacious accommodations sucking up floating liquids and playing with gyroscopes.

Then NASA embarked on a mission to take women and men into space on a regular basis in a reusable spacecraft to do important work – like putting the Hubble Space Telescope into orbit. But the Space Shuttle didn’t work out as we had hoped. It was massively complicated, difficult to service and extremely expensive. The Challenger and Columbia disasters more or less sealed its fate. The last shuttle launch was July 8, 2011, and since then all our astronauts have traveled to the International Space Station (ISS) on Soyuz rockets launched from Russia.

That’s about to change and if yesterday’s launch of the SpaceX Crew Dragon was successful, it already has. We are now in the era of private ownership of satellites, launch vehicles, and manned spacecraft. Soon we will have space tourism and commercial space travel a la 2001: A Space Odyssey.

Launched on Falcon 9 rocket, NASA astronauts Robert Behnken and Douglas Hurly will reach the ISS 24 hours later when the Crew Dragon docks itself. They will join the three astronauts currently on board.

Although the mission was first planned to last only two weeks, NASA released a statement that “the specific mission duration will be determined once on station based on the readiness of the next commercial crew launch.” This historic event marks not only the first humans launched into space on a privately owned spacecraft but also the first manned rocket to be launched from U.S. soil in nine years.

Next, I recently received an inquiry from a friend regarding the colors of galaxies as seen in photos from The Hubble Space Telescope. The HST uses CCDs to record incoming photons of light and it is sensitive not only to visible light, but also infrared and ultraviolet light which are invisible to the human eye. A star’s color depends on several factors, temperature, age, mass, size, but mostly temperature. So astronomers learn a great deal about the star’s temperature and chemical composition by analyzing the colors of the light it emits.

Galaxies are made up mostly of stars but there are also plenty of elements in gaseous form between the stars. Astronomers will often record images through various filters to study specific properties of the galaxy, such as the abundance of hydrogen or other elements. They then digitally enhance the photos to represent the different colors. These are usually accurate conversions where infrared would be represented by red, ultraviolet by blue, for example. Also, due to the expansion of the universe, extremely distant galaxies’ colors will be shifted toward the longer, red wavelengths.

A galaxy’s color will also depend on the age and mass distribution of its stars. Young, hot, massive stars emit mostly blue light while old, cool, giant stars are reddish. Betelgeuse and Rigel in Orion are examples.

Finally, June will offer several somewhat challenging opportunities for observing, beginning with the planet Mercury. Always a challenge, you will have to have a clear horizon and probably a pair of binoculars. Start by finding the stars Castor and Pollux in the western sky. Work your way down to about one fist-width above the horizon and you should be able to spot it. It won’t be very bright, but it will be pretty much alone.

Even more challenging will be a very close encounter between Venus and the crescent Moon on the morning of June 19. Starting around 5:30 a.m., scan the northeastern horizon below the Pleiades with binoculars or a telescope. With luck (and perfect weather) you will see the thinnest of crescents next to Venus. Then turn around to see Jupiter and Saturn in the southwest. I mention those two planets because next December they will put on a fantastic show up in the sky.

This month in history:
June 02: Surveyor 1 lands on the Moon – 1965
June 05: Regular observations of Neptune begun by Voyager 2 – 1989
June 10: Mars rover “Spirit” launched – 2003
June 16: Valentina Tereshkova first (and only solo) woman in space – 1963
June 18: Sally Ride becomes first American woman in space – 1983
June 22: Evidence of liquid water on Mars announced by NASA – 2000
June 30: Tunguska impact flattens hundreds of miles of Siberian forrest – 1908

May 04

What’s Up in the Sky

What’s Up in the Sky – May, 2020

Isolation Isn’t All Bad

Throughout history, pandemics have had considerable influence in the course of human events, some great, some small. Most experts agree that the current situation will end up being in the first category. So I did some research into the connection between pandemics and astronomy and found only one good example, but it’s a pretty important one since it changed the course of history.

I am referring to the work done by Isaac Newton during the plague years of 1666 – 1667. Already a brilliant scholar at Trinity College in Cambridge, England, Newton was forced to “shelter in place” at his home, a farm called Woolsthorpe, about sixty miles north of the university. Many writers make reference to how Newton, isolated from the distractions of daily life, would invent calculus, write equations to describe the science of motion and gravity, study the nature of light, and much more. The famous story of the falling apple is a snapshot of the time. The legend has it that the plague created the conditions that enabled modern science to be created.

Not so fast, says writer Thomas Levenson in a recent issue of the New Yorker magazine. According to Levenson, “Newton had begun to think about the most pressing questions in science while still studying for his exams . . . at Trinity College.” He also describes how Newton had worked on key problems and new approaches that would lead to calculus and a new approach to geometry, all before he left Cambridge.

When the epidemic finally subsided, Newton continued his work upon returning to Cambridge. He later wrote that, during the plague years, he had been “in the prime of my age for invention & minded Mathematicks & Philosophy more than at any time since”.

The legend is reinforced by the falling apple story. You have probably seen images where the apple falls on Newton’s head and all of a sudden a light bulb appears above it, indicating the birth of a new idea. Not really. It is true there were apple trees in the orchard at Woolsthorpe and that Newton observed them, but he merely used those observations to better understand and communicate the vast knowledge he had uncovered not only during the plague years but before and after them as well.

So the idea that inspirations come as bolts of lightening under just the right circumstances and that great discoveries don’t require years of intensive study by teams of highly trained individuals doing hard thinking is not really accurate. As Newton demonstrated, although a period of isolation frees the mind to narrowly focus on abstract problems, it takes a team effort and years of study to get a true understanding of what’s up in the sky.

This month in history:
May 05: Alan Shepard becomes first American in space – 1961
May 06: NASA announces that Canada will build the shuttle robot arm – 1975
May 11: First geostationary weather satellite launched – 1974
May 12: Adler Planetarium in Chicago opens, first planetarium in western hemisphere – 1930
May 20: Pioneer-Venus 1 launched – 1978
May 25: President Kennedy gives speech challenging nation to land astronaut on Moon before the end of the decade – 1961
May 29: First experimental test of Einstein’s General Theory of Relativity performed during total solar eclipse – 1919

Mar 30

What’s Up in the Sky

What’s Up in the Sky – April, 2020

A Great Month Ahead

I am excited about the coming month. Not only will there be some very nice observing opportunities and historic events to remember, but an event of great personal significance will occur, one which I plan to observe.

April will start off with a real bang, easily visible in the western sky after sunset. I am sure most readers have noticed the planet Venus shining like a beacon out over the lake after sunset. Next week observers will be treated to a spectacular display of orbital mechanics as Venus appears to pass through the Pleiades star cluster. Although it will be visible to the naked eye, binoculars will give you a better view of the planet passing close to individual stars in the cluster. A telescope aimed at the scene will allow you to witness the movement of the planet against the background star cluster. It promises to be a rare and beautiful sight!

Conjunctions of Venus and the Pleiades occur every year at this time, but rarely does the planet appear to pass through the cluster. However, every eight years nearly to the day, the planet crashes the party and becomes the brightest member of the group.

You can begin observing this event right away by watching each night as the planet inches closer and closer to the cluster. On April 3, Venus will be with the seven sisters for their eight year reunion. Don’t miss it. Even if the weather does not cooperate, don’t give up. This reunion will be visible all week and even one sighting will be worth it.

The following week the Moon may be seen passing close to the planets Jupiter, Saturn, and Mars. Unfortunately, you have to be up before sunrise to witness this event, easily visible low in the southeast.

Between these events, on April 7, will be a Supermoon – a full moon that occurs when the Moon is at the point in its orbit where it is closest to Earth, causing it to appear larger than usual. Although this phenomenon gets a lot of press, you really won’t notice it being any larger than usual unless you could view a side by side comparison with October’s full Moon.

At the end of this column you can see that April is an historic month for space exploration. I have always found it interesting that the first person in space and the first Shuttle launch occurred exactly twenty years apart and you can also see that this is the thirty year anniversary of the Hubble Space Telescope’s launch. But this month marks forty one years since one of my first, and greatest, astronomical observations.

You may have noticed the Moon, Venus, and the Pleiades forming a lovely triangle last night. On Saturday, April 25, the Moon will also have a close encounter with the bright star Aldebaran. A similar event occurred on Saturday, April 28, 1979, only that time, the Moon actually occulted (passed in front of) Aldebaran, blocking the star from view.

On that date, my wife and I were driving to Kalamazoo for a gathering of friends. It was a clear evening so, as Lyne drove, I watched Aldebaran approach the Moon’s unlit edge. I knew the occultation would happen soon, so when we arrived I told everyone to come outside and see it. Only one other person joined me.

It was the end of twilight with a crescent Moon. We both thought we would see the star fade out and disappear but instead, BAM! it was gone! Both of us were not only amazed at what a tremendous sight it was but also astonished that we were the only witnesses. When we tried to share our amazement with the others we got comments like, “. . . what’s the big deal, doesn’t that happen every night?”

Actually, no, it doesn’t. It may seem like the Moon should pass by many stars on its nightly journey through the sky, but actually, the stars are basically moving with it and most are not in its path. So occultations such as that one are extremely rare and when you consider timing, weather, and conflicting activities, it turns out to be one of the rarest of sights one can witness up in the sky.

This month in history:
April 01: Comet Hale-Bopp nearest Sun – 1997
April 02: First photograph of Sun taken – 1845
April 12: Yuri Gagarin becomes first human in space – 1961
April 12: Columbia is first space shuttle to be launched – 1981
April 17: Apollo 13 returns to Earth – 1970
April 25: Deployment of Hubble Space Telescope – 1990
April 28: Eugene Shoemaker is born – 1928

Older posts «