StarWatch for the greater Lehigh Valley

JULY  2013


Print Large Sky Charts For 10 p.m. EDT:   NORTH | EAST | SOUTH | WEST | ZENITH

[Moon Phases]
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Current Geomagnetic Field:  
Status Current Moon Phase
880    JUNE 30, 2013:   Cause of the Seasons Not Intuitive
The Earth is at aphelion or farthest from the sun on July 5 at 11 a.m., EDT. Just think about that. We will be coming off the Fourth of July celebrations with picnics, fireworks, tank tops, and togs in the fresh blush of summer, and yet we will be at our greatest distance from the sun. One of the big misconceptions that people have about the seasons is that they are a function of Earth-sun distance. Nothing could be further from the truth. They are attributed to the Earth’s axial tilt which “leans” the Northern Hemisphere towards the sun in the summer, so that Sol is higher in the sky and we receive more direct energy from the sun. This also allows the sun to be visible for a longer period of time throughout the day. The net result is an excess of energy, the Northern Hemisphere warms, and everyone goes outside to play. You can demonstrate this effect with a flashlight and a wall. The wall is the Earth’s surface; the flashlight represents the sun. Shine the flashlight straight down onto the wall, and note the area of the wall which the beam illuminates. Keeping the flashlight at the same distance from the wall, allow the light to strike the wall at angles which are less and less steep. You’ll notice the beam expanding into an oval which will elongate itself and cover more and more wall area. It’s the same energy but all spread out. This is what happens in winter when the Earth’s axis “leans back.” Daylight decreases, and the sun appears much lower in the sky. The energy received from the sun lessens and so do the temperatures. All of this leaning towards and away from the sun seems to indicate that the Earth’s axis flips back and forth during a year’s time. This is not the case at all. For now it points towards the North Star keeping the stars of the nighttime sky in step with the calendar. Oh, and how far are we from the sun on Friday, July 5? The number in miles turns out to be 94,508,200.

[Direct and Indirect Energy]
The seasons on Earth are not a function of the distance that Earth is from the sun, but rather the varying amounts of energy which are received from the sun due to the Earth’s axial tilt. Since flashlight beams are not precisely parallel like in the above illustration, keep the flashlight about the same distance from the wall or the ground to illustrate the outcome of changing angles more truthfully. Gary A. Becker slide...

881    JULY 7, 2013:   Scorpius Rules the Deep South
The summer is upon us, and as we head towards mid-July, I’m looking forward to seeing some of my favorite seasonal star patterns. Just like in winter when I look forward to witnessing Orion climb into the sky along with his entourage of winter favorites, summer brings with it a following of patterns that I anxiously await. Foremost are the stars of the deep southern sky that form Scorpius the Scorpion and Sagittarius the Archer. This week is a wonderful time to view the Scorpion because the moon is new on the 8th and won’t begin to interfere with stargazing until the end of the week. An online map is available. Try the Scorpion first by looking south at 11 p.m. Make sure you have no street lights to hamper your view. The first star you’ll notice, about 20 degrees off the horizon, should be the bright red supergiant Antares of the Scorpion. Its low altitude accentuates its redness and dims it slightly, but it is truly one of the best stars for its class. Bigger than Orion’s red Betelgeuse, if placed in the center of our solar system, Antares would stretch halfway between the orbits of Mars and Jupiter. At a distance of 600 light years, its total energy output is 65,000 times that of our sun, but because of its cool surface temperature, about 7000 degrees F., most of that energy spews from the star as unobservable infrared or “heat” energy. Thus, it is only the 15th brightest luminary in the nighttime heavens. Once Antares is located, three stars above and to its right form a gentle arc outlining the head. Southward of Antares, the Scorpion’s torso slants slightly to the left, ending in a sweeping curl that represents the tail and stinger. The tail is the most difficult part of Scorpius to view because of its close proximity to the horizon, but if you can see it, the scorpion comes to life as one of the truly beautiful constellations of the night. In two weeks, I’ll talk about Sagittarius.

[Scorpius the Scorpion]
See the Scorpion, Scorpius, low in the south at 11 p.m. at the start of July and at 9:00 p.m. near the end of the month. Gary A. Becker map using Software Bisque's, The Sky.

882    JULY 14, 2013:   One Small Step
I think everybody has a hero or someone they admire or aspire to emulate. One of mine was Neil A. Armstrong, the first human to walk on the moon. Neil unfortunately passed away last August 25 at the age of 82. I just finished James R. Hansen’s authorized biography of Armstrong, First Man, which filled in a number of gaps and some misinformation I had about the reluctant hero, whose first small step onto the lunar surface on July 20, 1969 forever changed his life and people’s perspective of the cosmos. “That’s one small step for (a) man, one giant leap for mankind.” This soft spoken and controlled human being, who paused to consider almost everything he said, forgot to say the “a” in that sentence. Without it, the words are redundant and make no sense, and although Armstrong insisted that the “a” was voiced, detailed audio analysis of that communication failed to reveal it. When were those words conceived in Armstrong’s mind? Hansen gives a credible argument that it probably didn’t happen until Armstrong had actually brought the Eagle safely down onto the lunar surface. There was no need to give it any serious consideration, according to Armstrong, until the landing had actually occurred, because Neil thought in his mind that the chances of accomplishing this feat were about 50/50. He gave the mission an overall 90 percent probability of successfully returning to Earth. Neil wasn’t even concerned about whether he or his partner, Buzz Aldrin, would be the first to walk. It was all about successfully landing the Eagle. Buzz, on the other hand, lobbied hard for that first step, but in the end NASA administrators unanimously chose Armstrong as the better person to represent humanity’s first explorer to set foot on another world. For Neil’s sake, kindly remember the “a” in “…one small step…” That was something he really wanted the world to know.

883    JULY 21, 2013:   Two Gems in Sagittarius
Two weeks ago, I spoke about Scorpius the Scorpion, with its reddish heart star, Antares, dominating the southern sky around 11 p.m. Far off to the right of Antares is Saturn in the SW. Follow the body of the Scorpion as it curves to the left to form the tail and stinger. To Scorpius’ left lies Sagittarius the Archer. If you witness a centaur, resplendent with bow and arrow drawn to kill Scorpius, may I suggest therapy; however, if you see a really cool teapot complete with handle, lid, and spout, you’ll be visualizing something which is considerably easier to see. A map is available at the URL below. One of my favorite open clusters of the heavens, M7, is located between the tail of the Scorpion and the spout of the teapot. If dark enough skies prevail, it is an easy naked eye target, especially if viewed with averted vision. The problem is its closeness to the horizon, only 15 degrees at its highest point (40 degrees N. latitude). View at 11 p.m. Often M7 goes unnoticed behind trees and buildings, or blends with pockets of horizon hugging light pollution and haze. Binoculars will reveal this gem with its stars splattered over a region nearly six times the area of the full moon. Its size is certainly a function of its closeness to the Earth, only 1000 light years distant. M7’s age has been estimated to be about 220 million years. You cannot view M7 without taking in the beauty of its slightly fainter neighbor, M6, above and to the right. At a distance of 1500 light years, M6 is a more concentrated grouping of stars than M7. It is also about half of M7’s age. Open clusters are sites where star generation has occurred. They differ from the older, larger globular clusters which formed in galaxies during the rough and tumble early days of the universe. Some astronomers believe that globulars were actually the first galaxies to form, and then were cannibalized into the larger galactic structures that we see today.

[Sagittarius the Archer]
See Sagittarius the Archer, low in the south at 11 p.m. during late July and at 9:00 p.m. by mid-August. Use binoculars to spot M6 and M7, two open clusters where star formation has recently occurred. Gary A. Becker map using Software Bisque's, The Sky.

884    JULY 28, 2013:   “Such Is a Day on Mars”
I have been having a lot of fun during the past few days working at the Mars Desert Research Station (MDRS) near Hanksville, Utah. Although the temperatures are very “unMars like,” 106 degrees F. yesterday, the scenery around the Habitat looks very Martian. Let’s see, what went wrong in the first few hours after our arrival? Hanksville had no electricity. The main generator which supplies electricity to the Habitat was broken, and the backup generator was cranky. The toilet in the shower area had not been cleaned, and the water in the main reservoir was going south and needed treatment. And get this, the backup generator just shutdown right as I was writing this, and now I’ve got about 30 minutes of battery life left in my computer before it too “dies.” As the commander of the MDRS Musk Observatory Refit Crew, Peter K. Detterline said, “Such is a day on Mars.” We are at MDRS for 12 nights, and so far we have been able to handle all of the distractions; but maybe the lack of electricity will be our nemesis and force us to retreat to the air conditioned comforts of a Hanksville motel. What a wimp I have become! Here I am complaining after just three days of Habitat living. The first crew that goes to Mars will spend some nine months just getting there, perhaps 18 months in exploration, and then another six months squeezed into a very small ship returning to Earth. Going outside to check on anything will require spacesuits, and a whole list of preparatory activities that Earthlings never consider in normal activity. How about a 20 minute wait in your spacesuit just for the airlock to depressurize? “Oh, I forgot my screwdriver” becomes 40 minutes of wasted mission time, pressurizing, retrieving the tool, and depressurizing again. Yes, all in a day on Mars. PS… We did find a fix for the generator and day three ended happily and productively.

[July Star Map]

[July Moon Phase Calendar]