Venus is Bright - By Contributing Astronomy Editor, Dan Matlaga

Aphrodite - Venus, Goddess of Love

How bright is Venus?

Venus is so bright...

...If you are observing from a dark sky site,Venus will cast shadows.

...Venus is the third brightest regular object in the sky.  The Sun and The Moon are the only two regular objects that can outshine Venus.

...Venus can be seen in broad daylight.

It is easy to see the planet Venus during the daylight hours because Venus is now brighter than the blue sky.

Four panels illustrate how simple it is to find Venus while the Sun is in the sky.

Go outside at 8:15 or so and face the West.  The two bright star looking objects are the planets Venus and Jupiter,  Venus is the one on the left, brighter and slightly higher than Jupiter.  Walk around so you can place Venus next to some landmark on your Western horizon.  Mark the spot  you are standing with a brick, stone chalk mark or whatever.

Next night stand on the same marker, look to the West but do this at 8:00 or fifteen minutes earlier than the first viewing.  You will find Venus will be above where you saw it a day earlier.

Walk around so Venus is once again lined up with a marker on your local horizon... a tree branch,  telephone pole,  neighbors house, or something. Mark where you are standing.

The third night repeat the same steps but now at 7:45.

The forth evening the sun should be above the horizon at 7:30.  If at first you can't see Venus keep looking.  Within 15 minutes it should appear where you saw it on the third evening attempt.

If you keep repeating these observations you may be able to continue until Venus will be visible to you at 5 or 4:00 late afternoon.  

The times given are for Tempe Arizona.  We do not have daylight saving time. We have too much sunlight for such childish things.  

Note:  Your first observing evening should correspond to a time when Venus is visible with a few background stars in your sky.

Editor's Note:  And lastly...Just for fun...here's what Frankie Avalon had to say about Venus back in 1959!                                                                                                                                  

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Venus and Jupiter, PART 4, by Contributing Astronomy Editor, Dan Matlaga

Venus and Jupiter - June 30, 2015

The evening of June 30 is our fourth and last conjunction of the planets in the evening sky. 

January 10th the planet Venus was associated with Mars and Mercury, January 20 our observations centered on Mars, the Moon and Mercury and February 20 with the Moon and Mars. 

Tuesday evening, June 30^th, Venus is in conjunction with the planet Jupiter. Look for two brilliant star-like objects in the western sky at about 8:00p.m. Venus will be the brighter of the two.

The pairing of these two planets in the evening sky will be so close, with only 1/3 of a degree separating them. As we discussed previously, the full moon appears about half a degree in diameter to our unaided eyes, so these two planets will be closer than the distance of the full moon. Without difficulty, you should be able to stretch out your arm and cover both planets with your thumb!

This paring, as with all of our observations on this topic, is an optical illusion.  Venus and Jupiter appear close to one another from our backyards due to line of sight perspective. Venus is 49 million miles away this evening while Jupiter is 563 million miles away.  Another way of illustrating the distances is to use the speed of light instead of miles. Light can travel around the earth eight times in one second. The light that strikes your eye from the planet Venus this evening takes 4.4 minutes to travel to your eye and the light from Jupiter takes 50 minutes to reach your eye.

There is one difference with the June 30 apparition from the three others reported on. With the exception of the moon, when Venus was paired with another planet, Venus would pass the planet then move higher in the sky each evening.  This evening is different.  Watch what happens evenings after Tuesday evening.  Venus and Jupiter simply separate from each other in an east-west direction, not above and below.  This is due to the fact Venus attained it's greatest apparent distance from the Sun June 6th.  Now the planet does not appear to move further from the sun, but closer.  

The result is the two planets will ride the skies together for a few nights.  August 14-15 Venus will move just south of the Sun and will be lost in the solar glare.

Venus, Mars and the Moon - February 20, 2015 - PART 3 - by Contributing Astronomy Editor, Dan Matlaga

              

FIGURE 1

If you were watching the western early evening skies this past week you would have seen the decreasing separation between the planets Venus and Mars (Figure 1). Minimum separation occurs Friday evening with the addition of the thin crescent moon.

FIGURE 2

The view of the western early evening sky of February 20 is illustrated in Figure 2.  Venus outshines both the moon and Mars.  Although the moon is represented in Figure 2, it does not register at the resolution of the figure, though the moon will be easily visible to the casual observer facing west.

FIGURE 3

A pair of binoculars might enhance the naked eye view.  Figure 3 is the view through a pair of 7X35 binoculars.  This is a popular size of binocular.  The first number "7" designates the magnification of the binocular. The size of the large lenses furthest from your eye while using the binocular provides the diameter of the lenses in millimeters, in this case "35" millimeters or roughly 1.5 inches.

 Note the image of the moon.  It consists of a bright crescent.  That bright crescent is the part of the moon illuminated directly by the sun, light from the sun reflected off the moon to earth.  The rest of the moon has an ashen look.  The ashen light is the result of light from the sun striking the earth, reflecting off the earth to the moon, then reflecting off the moon to the earth and into your eyes.  Not bad for the moon which reflects on average only 12% of sunlight, and is therefore a very dark object. This view of the moon has been described as: "The old moon wi' the new moon in her arms."

The scene before your eyes the evening of the 20th is somewhat of an illusion. Venus, Mars and the Moon are not that close in space.  We can illustrate this using the speed of light. A beam of light can travel 8 times around the earth in one second, yet that same beam of light takes about 8.3 minutes to travel from the sun to the earth. We say then the sun is 8.3 light minutes away from the earth. On the 20th of February the sunlight reflected off the moon takes but 1.2 seconds to reach the earth, Venus nearly 12 minutes and the reflected sunlight from Mars takes 18 minutes.

This is the third of four submissions concerning the planet Venus in the western evening sky. As you observe the Moon, Venus and Mars this evening, you might take a second to look directly east.  The brilliant star like object hovering directly above east is the planet Jupiter.  

The very close appearance of Venus and Jupiter above the western horizon the evening of June 30th will be the 4th of 4 postings.  

The separation between Jupiter and Venus is decreasing already. Look tonight to the west at Venus, then to the east at Jupiter... the June 30th event has begun! 

Contributing Editor, Dan Matlaga: Astronomy Event 4/13 And Other Cool Stuff!

Welcome back Contributing Editor, Dan Matlaga!  You may recall from  Dan's first post that in addition to his degrees in Astronomy and Geology, Dan recently retired from a 36 year career teaching Astronomy at Arizona State University via their planetarium - which was very interactive and "hands-on" at the planetarium itself.  Dan will continue to educate us on the subject of astronomy, including keeping us informed on current "happenings in the sky", such as the event that begins tomorrow, Saturday, 4/13.

Of course, Dan was also one of Joe's closest friends from their teen years.

So now, here is Dan with not only the info. on the Saturday event, but several other cool treats as well.  Take it away, Dan...

Just last week on PBS, the Nova program was an excellent treatment of the Greek Antikythera machine. The machine, about the size of a laptop, was billed as the world’s first computer.  It was found as part of a shipwreck in 1901.  The mechanism is at least 2,000 years old. The encrusted gears remained as an interesting museum piece until the late 1950’s when an English physicist examined it and discovered it was capable of predicting the positions of the sun and moon on a kind of clock face.  

Clearly there were more gears to the device, so one could conclude the machine was capable of more than positions of the sun and moon.  The PBS show demonstrated how the mechanism was capable of illustrating the positions of the sun, moon and five naked eye planets.  It was capable of predicting lunar and solar eclipses as well. 

The history books dedicated to the path of western technology will have to be rewritten as a result of this machine!

                                      Watch Ancient Computer on PBS. See more from NOVA.

I recall David Van Pelt bringing up the subject of this machine early in the 1960's.  He'd read an article about it in an old issue of Scientific American.  Joe Egles and I listened intently, athough we were not as familiar with computers.  Our discussions on the subject centered on the classic Orrery, a geared model of the solar system on the ceiling in a circular room at the Hayden Planetarium in New York City.  We agreed if we ever made it to Athens, the Antikythera machine would be tops on our list. 

The three of us had a great respect for the sheer pleasure of knowing things.  Though I don’t ever recall a discussion on sports or the latest cars, our minds drifted through the fields of science and technology. If we three were together this Saturday evening, April 13^th, our thoughts would be skyward, specifically toward the west just after sunset.

Immediately after sunset, look above where the sun sets for the 12% illuminated crescent moon.  When the first stars appear, you will be able to find the bright “star” above the moon.  That is not a star but the planet Jupiter.  Between the moon and Jupiter, but slightly to the left, is the fainter red star Aldebaran, the eye of Taurus the Bull.  When it gets darker there will be an unmistakable letter “V” formed by dim stars.  The “V” represents the face of Taurus with Aldebaran forming the upper left part of the “V”.  A line drawn from Aldebaran through the moon, continued on the other side of the moon at a little more than the Aldebaran moon distance, is a faint group of seven stars known as the Pleiades. You can hold your thumb with extended arm up to the sky; your thumb will cover the Pleiades. 

How easy is it to locate these objects? The moon and Jupiter should be easy.  Aldebaran is fainter than the moon and Jupiter, but the close proximity of the moon and Jupiter should pose no problem provided the sky is dark enough and you have a clear western horizon, uninterrupted by trees or houses.  Chances are you may be able to locate only five or so Pleiades due to their low altitude. It helps if your local sky is reasonably dark and you are experiencing low humidity.  Just a few weeks ago here in Tempe, Arizona the humidity was 2%, with an increase of 3% after sunset. If you can find these objects, the stage is set.

Various Sky Viewing Conditions

The Pleiades are called the Seven Sisters.  To some Greeks they were known as the Seven Doves.  In our modern world, as well as millennia ago, the dove can be the symbol of the human spirit.  In an article for submission next winter, I’ll explain how the “V” in Taurus represents the physical.

So there you have it.  Early this Saturday evening the moon is between the symbols of the physical, the ”V” of Taurus the bull, and the spirit, the Pleiades. 

We learn in grade school the earth orbits the sun. The effect of this motion is to make the sun appear to travel two solar diameters across the sky each day in front of the far more distant stars.  Like the moon this Saturday, the Sun will appear to travel between the “V” of Taurus and the Pleiades.  In fact the position of the moon Saturday is about the same position the Sun will occupy on May 20th. 

A return to chaos occurs in classical mythology whenever a symbol disappears.  In this case the very bright sun forces the star symbols of the physical and spirit to disappear from our view; chaos between the physical and the spirit ensues.

How long will the chaos of physical and spirit last?  According to the Greek historian Hesiod in his “Works and Days", the Pleiades disappear from view forty days and nights.  This is an interesting number. Not only are there many references in the old and new testament of the number forty, we find it in relatively modern literature.  It is Ahab’s fortieth year at sea since becoming a boy harpooner that is described in Herman Melville’s Moby-Dick. The hunchback of Notre Dame brings the princess into the church, climbs up to the tower and shouts: “Sanctuary,” to the crowd below.  By declaring sanctuary the police cannot enter the church to rescue the princess for forty days.  We have the stories of Ali Baba and the Forty Thieves as well as the traditional period of quarantine lasting for forty days.

If you watch the Pleiades, you will notice with each passing evening they will appear lower and lower in the sky until they will no longer be visible on May 1^st.  They will reappear about June 9^th; when the Pleiades will emerge from the bright sunlight in the East, just before sunrise.

With so much riding on the observation of the Pleiades and other celestial bodies, is there any wonder why the Greeks would try to bring celestial observations down to earth to better predict the motions of the heavens in the Antikythera machine? 

You can stand out in the evening twilight over the next few weeks and watch as the Pleiades slide into the light of the sun and appreciate how this view inspired societies throughout time and place.

We have made great progress in representing the sky.  An excellent free download to your computer is the program Stellarium.  It is free and can recreate the skies from your backyard.  I hope to present more submissions that will be easier to follow if you have Stellarium on your computer.  It can create, among other things, this Saturday’s evening sky.

Here is a video about the Stellarium software.  Click on this link to download it for free!  http://www.stellarium.org/

Thank you so much, Dan - that was awesome!  Hope to see you again soon.  Can't wait to see what you have planned for us next.  We will download the  Stellarium software (I already have) and be ready to follow along!