Jupiter in Broad Daylight

April 14, 2013 Update: Last month the Moon passed Jupiter at a time that allowed (relative) easy sighting of Jupiter in broad daylight…. with the unaided eye. In fact it was the best opportunity for several years to come.

(The image here represents the relative position of the Moon and Jupiter about a half hour before sunset today as seen from Denver. Specifically, the view is facing West at 7:07 p.m. MDT, about 47 degrees above the horizon.)

But if you missed the chance then, try again today. The conditions are not quite as good, but throughout North America the Moon will be to the left (or slightly above and to the left) of Jupiter in the last half hour or so before sunset. The two will be separated by 3 to 4 degrees (6 to 8 lunar diameters), depending on the observers geographic location and time of observation.

Of course, the observation may be made earlier in the day, but the last half hour before sunset will generally provide the best chances, dependent on local weather conditions. I suggest setting the observation up in a good graphical planetarium program ("Starry Night" for example) beforehand. There are more observing suggestions in the original article below. (However, remember that the specifics listed below, including the graphics, are for the now past opportunity in March.)

April 15 Update: I tried several times yesterday evening, starting about 45 minutes before sunset, with no luck. Then I did indeed catch Jupiter, with the unaided eye, at 7:31 p.m., just 6 minutes before local sunset. Due to strong winds and probable dust in the air (or perhaps high thin clouds from an approaching storm system) the sky was less contrasty than it could have been. Aside from that, I suspect I would have caught it even earlier.

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Not many know it and fewer have actually done it, but the planet Jupiter can be observed in the daylight sky under good conditions… with the unaided eye. Most everyone knows that the Moon can sometimes be seen in full daylight, and most amateur astronomers have glimpsed Venus once or twice with the Sun still in the sky.

Some have even reported observing the bright star Sirius in the daytime sky, although I have to say that if this is true, if must have been as a result of exceptional eyesight under remarkable atmospheric circumstances. In fact the academic studies I have read relating to the daytime observation of stars strongly suggested that no star is bright enough to be seen in the daylight without optical aid. Based on my experience I think this is true.

Three planets, however, can be seen if the conditions are right. They are Venus, Mars and Jupiter. Venus is not much of a challenge, and in fact is pretty easy if you know when and where to look. However, even at their brightest, Mars and Jupiter are only about one sixth as bright as Venus and present significantly greater difficulty. Seeing  Mars with the unaided eye in the daytime is not going to be reasonably possible for some time, so let’s just consider Jupiter.

If you have reasonably good eyesight, and know when and where to look, you can join a very small group of observers who have caught the giant planet in broad daylight, without a telescope. Although I have yet to observe Mars in the daytime (haven’t actually tried), I have clearly and distinctly observed Jupiter 3 times in daylight over the same number of decades.

So how do you do it? As with many things, it’s all about timing. First and foremost, you must find a time when Jupiter is as high in the sky as possible just before sunset. In general the sky is not as bright in late afternoon as it is at midday, so Jupiter will stand out better in contrast. Being as high in the sky as possible ensures that Jupiter’s light passes through the smallest column of air before it reaches your eyes, minimizing absorption of its light. Essentially, what this means is that what you want to do is choose a time of year when the Ecliptic is highest in the sky at sunset (which is in the Spring) and when the Sun and Jupiter are in "quadrature," which is just a fancy way of saying that the two are separated by 90 degrees (or 270 degrees) in the sky. These conditions are met best during one spring every 12 years. (The years before and after are possible, too, those not as easy.)

As it turns out, March 2013 offers the best chance for the next 12 years. (Again, not the only chance, mind you, but the best.)

Now, to make it even easier, it would be nice to have a "landmark" in the sky to help you locate Jupiter. Enter the Moon, stage right. As it turns out, the Moon’s trajectory in the sky is very similar to Jupiter’s, so we need to pick a time when the Moon passes near Jupiter shortly before sunset.

All these factors come together this weekend, when the nearly First Quarter Moon passes near Jupiter, high in the southern sky shortly before sunset. Of course the Moon will be near Jupiter all night until they set around midnight, but you want to view in, say, the last half hour before sunset. Saturday, Sunday and Monday will do, but Sunday (3/17/2013) is by far the best day this time around.

Before observing, get a star chart showing the position of the Moon and Jupiter at the time you want to observe. You can get these in many software products, including a number that are free. (The graphic near the top of this page shows the Moon with Jupiter as a tiny speck above it, facing roughly South at about 6:30 p.m. Sunday as viewed from Denver. Click on it for a bigger view. Several other cities are listed below.)

Stand somewhere with a clear view of the southern sky, but out of direct sunlight or strong reflections.  It may help to “cup” your eyes or use some other method to reduce the excess light. Then locate the Crescent Moon in the southern sky at around 6:30 pm local time and scan the area with binoculars. Once you find Jupiter in the binocs, try it with just your eyes.

The previously mentioned image near the top of this page is a screen save from “Starry Night” software showing the Moon and Jupiter (small dot above the Moon) set for Sunday afternoon at about 6:30 p.m. as seen from Denver.

Here are screen saves for several US cities (use list view):

3/17/13 Moon/Jupiter (various cities) VIEW SLIDE SHOW DOWNLOAD ALL

We have considered only late afternoon observations here, but similar reasoning holds for early morning observations. In fact, early morning observations are even easier in a sense because you can observe Jupiter or Mars before sunrise, then track it into the daytime sky. But for this time around, it is afternoon observations only.

Of course, if you have a "go to" telescope you can just find Jupiter that way, and then attempt an unaided eye observation. But frankly, I think that this is kind of copping out. Still, use a crutch if you must.

For more, see my article on EarthSky.org:

10 surprising space objects to see in the daytime sky

Postscript:

The exact appearance and orientation of Jupiter and the Moon in the sky may not be precisely as shown in the graphics, depending on the observer’s exact geographic location, time and direction facing. If you use a clock-face analogy, a straight up-down line defining the 6 and 12 positions may indicate Jupiter at, say, an 11 o’clock bearing from the Moon. However, a more accurate way of using these graphics is to imagine the 6-12 hour line on the clock face as running from the bottom cusp of the Moon’s crescent to the top cusp, and then orient the position of Jupiter based on that.

Also, scanning with binoculars is very helpful, but be sure you are accurately focused on the Moon first (to establish a clear focus). Even being slightly out of focus will blur the image of Jupiter and make it harder to see.

You might think that the best time to view Jupiter or Mars would be when the planet is at its greatest magnitude (brightness). Actually the magnitude of Jupiter doesn’t vary all that much, but Mars does. The problem with viewing at actual greatest magnitude is that for superior planets (those farther from the Sun than the Earth) this occurs near the time of opposition, meaning that the Sun and the planet are on opposite sides of the sky (like the situation with the Full Moon). Thus the planet will be rising as the Sun is setting, and at best the planet will be positioned very low in the sky in the late afternoon. The Earth’s atmosphere filters out a lot of the light coming from objects near the horizon, not just dimming them but also changing color and making stars twinkle. (Have you ever seen an orange or red Moon rising?) In addition, the effects of haze or pollution are increased near the horizon, dimming objects further. For these reasons, trying to observe Mars or Jupiter in the daytime sky at the time of a planet’s greatest magnitude may not be a good idea.

Some advocate using polarized glasses because they tend to darken the sky about 90 degrees away from the Sun, which in theory should increase the contrast between the sky and Jupiter. I have not really tried this method, but I note that using polarized glasses or a polarizing filter not only will darken the sky, it also will darken the image of Jupiter, making it even harder to see.

Smaller Colorado River projected for coming decades, study says | e! Science News

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Some 40 million people depend on the Colorado River Basin for water but warmer weather from rising greenhouse gas levels and a growing population may signal water shortages ahead.

See on esciencenews.com

Is Our Universe the Ultimate Free Lunch?

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The inflationary model suggests an elegant solution to the puzzle of why our universe is expanding. But what happened before that? How did the universe get to that state?

Larry C. Sessions‘s insight:

The "free lunch" idea is not new, but this is an interesting explanation.

See on www.huffingtonpost.com

I am voting, without apology, for Barack H. Obama

Read this at your own peril. I am not a communist, a socialist, nor an Islamist. Neither is Barack H. Obama. We are both Americans by birth, and both committed to the American ideal, which puts the betterment of the whole over the betterment of the priveleged and the well-to-do. This is a fact of the which Barack Obama is clearly honest. I fully agree. I sincerely and utterly abhor the lies and distortions of the Republican candidate.

Let me be clear. I do not fully or in many cases even partially agree with the policies of Barack Obama. I many ways, especially in regard to the environment, gLobal warming and wildlife, I think that Obama has been too weak and too willing to compromise on important issues for political gain.

But I also understand that Obama is in an incredibly difficult situation, and must choose amongst options which in many cases range from horrible to at best, less bad. It is not an easy situation, and I do not always agree, but I am firmly convinced that his choices, overall, have been considerably better than his predecessor and clearly better than the choices that are likely to be made my Mitt Romney if he is elected.

My Dad was a Marine. This whole blog was precipitated by an article about a MArine who came back from overseass as a triple amputee, and who has, as the epitome, has made much of himself, despite the arrogance and self-importance of those who advocated sending this now American hero into the line of fire for their own personal gain. Clearly, and without any question whatsoever, this Marine is a true American hero who deserves anything reasonable that this country can offer in orly partial consideration of the enormous sacrificed that he has made. I note that the same is true for many female veterans.

(For the record, I grew up during the Vietnam era, but never served in the military.) Once a Marine, always a Marine, but my DAd is gone now. He lived to 96 and has been gone for almost exactly 3 years, having passing away on Saturday, 24 October 2009. He and I had many issues and I cannot speak for him. However, despite his gruff exterior, he always favored the poor over the well-to-do, the disadvantaged over the privileged, the meek over the arrogant. He was not in favor of the abuses of unions and clearly preferred the independence of ultimate personal responsibility over the faux security of unionization or the arrogance of corporations. These are values he imparted to me, and while we had great differences, I am grateful for what he taught me.

I do not think that I am out of line in saying that I am sure that my Dad would have preferred the middle-class centered approach of Obama over the arrogance and transparent lies of Romney.

The vast majority of American military come from lower to middle-class backgrounds, as did my Dad and as do I. I just hope that all can understand that intelligent compassion is greater than arrogant strength. We cannot back down from direct attacks and we need a strong military to combat evil where ever it arises. On the other hand, it is wrong to ignore the needs of the American people and the safety of those brave souls who protect us, in favor of protecting the foreign investments of corporations and individuals who prey on the patriotism of ordinary Americans.

Every adult has a right, an obligation, to express his or her opinion and to participate in the American way, the American process. You may not agree with me, but I favor the average person and the underprivileged over the well-to-do. I prefer logic and rationality with compassion over complete personal interest. I believe that while humans are a part of Nature and we obviously have every right to express our opinions and desires, we are just a portion of the whole picture. I believe that the “right” action is the one that favors the majority over the individual, the masses over the rich, and the weak over the artificially strong.

You might think that my views are Communist or Socialist, and if you do, all that shows is your ignorance of what being an American is all about. Communism in particular is an idealistic view that is easily corrupted through the abuse of power, and perhaps the weakness of individuals in opposing it. The evil of Communism and its failures lie much more in the arrogance of power and force of personality than in the meekness and compliance of the public. I am in no way absolving a people or a population from responsibility in the abuses of Communism, but it is clear (to me at least) that a poorly educated populace is easily manipulated, easily corrupted.

Our decades long de-emphasis on personal responsibility, the absence of critical thought in schools,and an open system that allows — even encourages — lies from the corporate structure, places the American public at a disadvantage that works to the advantage of the privileged, the wealthy, and the unscrupulous. Sadly our system works to the advantage of the rich and to the detriment of the poor and middle classes. Don’t be hoodwinked and literally lied to by the well-heeled and rich. Use you intelligence and your common sense. Vote accordingly. Vote for the advantage of the many over the privileged. I am not against the privileged, but it is clearly UN-AMERICAN to think that they are more deserving that the average person.

I am not a huge fan of Barack Obama. But he is clearly more in favor of the individual — the teeming masses if you will — privilege and arrogance, so clearly evidenced in the form of Mitt Romney (Wop, by the way, apparently is ashamed to go by his real first name, Willard. To be clear, “Willard” is a fine name, so why is “Mitt” so ashamed of it (rhetorical question, consider as you will. although I will notice that Obama’s first name is indeed “Barack” about which he is clearly an honest.

I will vote for Obama, and my fervent hope is that America will come to the understanding that the best interest of our Country, and the world, is a society that values the contributions of the middle class and even the poor over the arrogance of the rich.

The Equinox: When day and night are not equal

A lot of people know that on the Equinox, every location on Earth is supposed to get 12 hours of daylight. In fact, the term “Equinox” means “equal night,” signifying that the period of night should equal the period of daytime, and since the day is 24 hours long, we should have 12 hours of each. This year, the September Equinox occurs at exactly at 8:49 a.m. Mountain Daylight Time on Saturday, September 22. At that moment, Autumn or Fall begins for the Earth’s Northern Hemisphere. [Note that I avoid calling it the "Autumnal Equinox" simply because that is true only for half of the Earth. In the other half, the Southern Hemisphere, the same event marks the transition from Winter to Spring.]

So it might be expected that September 22 would have exactly (or almost) 12 hours of possible sunshine and 12 hours of night. But it doesn’t. A simple check of sunrise and sunset times will show that there are more than exactly 12 hours on that date. In Denver, the Sun rises at 6:48 a.m. and sets at 6:56 p.m., with each time rounded to the nearest minute. This yields 12 hours and 8 minutes.

In reality, no day has exactly 12 hours of sunshine. In Denver, the day that most closely matches this is September 25 this year. (It changes a bit from year to year, due mostly to the Leap Year cycle). Rounded to the nearest minute, the Sun rises at 6:51 a.m. and sets at 6:51 p.m. on September 25th in Denver. Much the same is true for other cities. (See link below.)

So are astronomers, who normally are very accurate, wrong on this one? Is the Equinox really on the 25th this year?

No, the astronomers are correct. The Equinox occurs at 8:49 a.m. Mountain Daylight Time on the 22nd (this year). Astronomy is an observational science, but in this case, observations can be misleading. The times of sunrise and sunset are given for the apparent rise and set times. In other words, given clear skies and an unobstructed horizon, the times given are those that the Sun would be seen to rise and set. The key word here is “apparent.”

The fact is that the Sun appears to rise a few minutes before it actually crosses the eastern horizon, and stays in the sky a few minutes after it has, in fact, disappeared below the western horizon.

The reason lies with the Earth’s atmosphere, which bends the sunlight around the horizon. It is somewhat like peering around the corner with a periscope. The atmosphere bends the Sun’s light around the horizon slightly, such that the Sun appears in the East a couple of minutes before it actually rises. In the evening the reverse happens – the Sun’s light is bent around the horizon to cause the Sun to remain visible for a few minutes after it has really dipped below the western horizon.

This is known as refraction, a fancy way of saying bending, due to the atmosphere. It is the same effect that causes a pencil stuck in a glass of water to appear offset slightly. Truth is, when you sight along the horizon, you are looking through much more atmosphere then when you look high in the sky. Because of this, the refractive effect is much greater near the horizon, even allowing objects that are technically just beyond the horizon to appear.

Thus on the day of the Equinox the theoretical period of sunlight is 12 hours, but because of this refraction or bending of sunlight around the horizon, the apparent day is longer.

However, at this time of year the days are getting shorter. So a few days later, when the theoretical period of sunshine should be significantly less than 12 hours, the lengthening due to refraction brings it up to 12 hours even (or almost).

So the Equinox occurs on the 22nd, but the day with 12 hours of sunshine comes 3 days later. (Again, this can vary a bit with geographic location…. for example, in Houston it is on the 26th). In the Spring, the opposite effect occurs. As days get longer, the observed equinox comes a few days before the official Equinox.

(If you are not lucky enough to live in Denver, you can compute the rise and set times for your location from this US Naval Observatory page: http://aa.usno.navy.mil/data/docs/RS_OneDay.php)

Pale Blue Dot – Animation

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I’ve been enrolled in illustration at Sheridan College for the the last 4 years and this is my final thesis project.

See on vimeo.com

“Defying” Gravity?

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It really annoys me to hear people say that someone is defying the “Law of Gravity.” You cannot defy gravity, you can only work within its bounds. You can apply sufficient force in the opposite direction to compensate for gravity, or even surpass it in a given direction. You can lift a cup, walk across the ground, climb stairs against the force of gravity, jump up in the air, or even fly. But in my mind that is not “defying” it, which to me at least carries a bit of human arrogance. When you do these, you are simply working within the limits it allows. You can travel to space to experience “weightlessness,” but you still are under the influence of gravity. The net force of gravity can approach zero, not by defying it, but by arranging opposing sources of gravity of equal strength.

 

At some point between galaxies, an astronaut would not experience gravity, and hence would feel “weightless,” but gravity is still there. Astronauts in the ISS are pulled with about 90% of the force of gravity they feel at the planet’s surface. In fact, gravity is “universal,” which means that even if you traveled as far as the farthest galaxy, you would never completely remove yourself from Earth’s gravitational field (nor that of any other object in the Universe).

 

You can hold up your hand to shield yourself from the Sun, or tunnel deep underground where none but neutrinos dare, but gravity is still there. You cannot shield it. It is the most pervasive aspect of existence.

 

You may think I am just being picky, and I am. But I think a little more clarity in language might help avoid some of the many, many misconceptions people have today about science and other aspects of life. You can defy your parents, your boss or your government. But you can’t defy gravity. It’s the law.