Wednesday, July 26, 2017

Eclipse Corner #9 Projection: Pinhole & Optical

    For enjoying the approximately 3 hours of the total eclipse on August 21, one must provide themselves with a way to look at the Sun without endangering their eyes. Eclipse glasses (available at many sites), #14 welding glass, or solar filters are excellent possibilities. However, several projection methods may be helpful. A handheld Pinhole projection method is the easiest and old fashioned method and it is simple and easy to set up. Telescope and binocular projection can work but care must be taken. Care must be used especially when magnifying the Sun.  Keep Safe!

     

     Note that pinhole projection does not mean looking at the Sun through a pinhole!  The steps to make a pinhole projector are as follows: 
1.Take a sheet of paper and make a tiny hole in the middle of it using a pin or a thumbtack. Make sure that the hole is round and smooth. 
2. With your back towards the Sun, hold the paper with the pin hole above your shoulder allowing the Sun to shine through.  
3. The 2nd sheet of paper will act as the projection screen. Hold it at a distance, catch the sunlight, and you will see an inverted image of the Sun.  
4. To make the image of the Sun larger, hold the screen paper further away from the paper with the pinhole. You are not looking at the Sun but a projection on a piece of paper.

     Compared with pinhole projection, optical projection generally provides bigger, brighter, sharper images. Optical Projection can use a telescope or binoculars to project images of the partially eclipsed Sun onto a surface for convenient viewing. This is called optical projection, because it involves optics (that is, lenses and/or mirrors). A reflective scope with a small 4 to 6 inch mirror is plenty big enough to project large images. 


Sky and Telescope

      The following are steps for setting up a projection for a reflecting telescope: 1.Take the spotter scope off the telescope.  
2. Place the telescope on a tripod with open end facing the sun. 
3. With back toward Sun, use the shadow of the telescope to center the view. 4. Place a white paper or poster board on an easel opposite the eyepiece. 
5. Light will go through the scope and be magnified on the poster board. It can be focused with the knob at the eyepiece. Distance can be changed to maximize the size of projection. 
6. A dark colored pencil will smoke and catch on fire if placed where your eye would normally be placed at the eyepiece. This example should emphasize the importance of NOT LOOKING THROUGH THE EYEPIECE AND/OR TELESCOPE.  Maybe you can cook hotdogs at lunch. 
7. The round perception of the bright Sun will show the shadow of the Moon crossing and producing the eclipse. Do Not Leave your scope unattended. Basically it is a two man setup with one working the scope and the other handling the poster board.


     This can work with a refracting telescope or binoculars (block one side of the binoculars to avoid difficulties). The heat of the Sun coming through the lens can built up. One should be careful and handle lens and eyepieces to check for heat.  If it is getting hot, stop operation for a time and allow cooling. Again the white poster board is catching the light, not your  eye(s).

      Always keep your back towards the Sun while looking at a pinhole or optical projection. Normally, the less magnification telescope eyepiece is best. Some of these setups can be practiced before the eclipse date so you are confident that the projection will work. More information will be coming up with the Eclipse Corner soon, and the date is getting closer.             – Dan Slais

Join us August 18-21, 2017 for Midnight at Noon, a four day music festival and eclipse viewing event in Owensville and Rosebud, MO.  Visit our website 


Monday, July 24, 2017

Eclipse #8 Getting Ready for the Solar Eclipse

     The 2017 Great American Eclipse totality path covers only mainland United States and no other countries. Fourteen states will be touched by this eclipse totality: Oregon, Idaho, unpopulated less than 8 square miles of Montana, Wyoming, Nebraska, 450 acres of Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina, and South Carolina. The entire North American continent will see some amount of partial solar eclipse.

     A website http://aa.usno.navy.mil/data/docs/SolarEclipses.php from the Solar Eclipse Computer of the U.S. Naval Observatory Astronomical Applications Department will allow a person to simply list city or town and state and it will calculate the obscuration or percentage of the Sun eclipsed. An example would show that a person who lives in the town of Rolla, Missouri, would note the obscuration is 99.9% and they will want to check a map to figure how to reach totality.




     A total solar eclipse is widely regarded as the ultimate astronomy event, and the greatest natural phenomenon of any kind. Making ready for and making plans for the eclipse is critical to the success of the experience. First, is getting to the centerline for 100% totality. Michael Bakich, Astronomy Magazine said it perfectly, “It’s all about totality. Not to cast a shadow on things, but likening a partial eclipse to a total eclipse is like comparing almost dying to dying. Only totality reveals the true celestial spectacle.”
     Astronomy Magazine editors advise some of the following considerations: 1. Find an accessible, comfortable, open sky spot to go (near the centerline of totality, of course), 2. Take August 21, eclipse day, off and since it is a Monday maybe you should make a 3 day weekend out of the eclipse, 3. Attend an eclipse event. There are several special eclipse goings-on set up especially near the centerline of totality, 4. Get involved and consider volunteering with a group putting on the eclipse event. You will learn a lot and meet people, 5. Stay flexible, you might need to move, due to weather and traffic could be difficult, 6. Make sure you have your viewing procedures set up in advance. Have your “Eclipse Glasses” ready, 7. Use the restroom well before the action starts, 8. Get comfortable and bring a chair, hat, sun screen and /or an umbrella, a table, snacks and drinks, 9. Bring a good attitude, 10. Remember, you can not completely prepare yourself for emotions for the total solar eclipse happening. When totality arrives, you will experience primal emotions and wonderment.
     Shortly after the eclipse, when the event is still fresh in your mind, take some time to write, voice record, or make a video of your memories, thoughts, and impressions. A decade from now, such a chronicle will help you relive this fantastic event. Have friends join in too by sharing what you have just experienced. Possibly an after-eclipse party or meal can help wind down the good time and emotional high. Fun!
     So far, much of the American press and public are completely unaware and unappreciative of the wonder that will pass over millions of people next August. This is not surprising since an entire generation has grown up without this experience, and moreover, there has not been a coast-to-coast American eclipse in a century. It is important that the press and the public wake up and become aware of this unprecedented event, and that as many people as possible can make plans to participate. This is especially true of the children, who can hope to see five American total solar eclipses within the next 35 years. The Eclipse Corner will continue to supply astronomical information.                                                                                                            –Dan Slais

Join us August 18-21, 2017 for Midnight at Noon, a four day music festival and eclipse viewing event in Owensville and Rosebud, MO.  For more information click here

Wednesday, July 19, 2017

Eclipse Corner #7 Safe Looking at the Solar Eclipse

     Philip S. Harrington says in his book Eclipse! , “The Sun holds the dubious distinction of being the only celestial object that may actually harm someone who looks at it directly.” Your eyes will tell you after a slight glance toward the Sun, they turn you away. What makes looking at the Sun so dangerous? The sun not only radiates visible light, but its photosphere or surface emits infrared and ultraviolet radiation. “Just as ultraviolet radiation causes sunburn to exposed skin, so too will it damage your eyes’ retinas. The human eye needs only direct sunlight for a few seconds before permanent eye damage, and even blindness, results. Since there are no pain receptors in the retina, there is no feeling of discomfort as eye damage occurs.” Totality is the only time when it is safe to look directly at a solar eclipse without protection.  

     In the NASA Eclipse website, expert Fred Espenak says, “Do not attempt to observe the partial phases of the total eclipse with the naked eye.” Even when 99% of the Sun’s surface is obscured or covered, the remaining photospheric crescent is intensely bright and cannot be viewed safely without protection. The responsibility for following all safety precautions in using any suitable viewing equipment or methods and in following proven safe viewing practice, lies solely with the person who owns the eyes that are viewing the eclipse.


     At most sites, groups of watchers, schools and communities are providing inexpensive but safe solar Eclipse Glasses or handheld Solar Viewers to view the eclipse. These glasses are made from exclusive scratch resistant, optical density 5, “Black Polymer” plastic type material which has exceeded the rigorous ISO 12312-2: 2015 international standards for safe direct viewing of the Sun and to filter harmful infrared and ultraviolet radiation. You can always check. The ISO requirements will be printed on the glasses.


The American Astronomical Society website shows this check of eclipse glasses on the earpiece of glasses.

     The American Astronomical Society offers tips for viewing the solar eclipse:  Always inspect your solar filter or glasses before use, if scratched or damaged, discard it; read and follow any instructions printed on or packaged with the filter; always supervise children using solar filters; stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright Sun; after looking at the Sun, turn away and remove your filter — do not remove it while looking at the Sun.  Remove your solar filter only when the Moon completely covers the Sun’s bright face and it suddenly gets dark. Experience totality, then, as soon as the bright Sun begins to reappear, replace your solar glasses to watch the remaining partial phases. To date, four manufacturers have certified that their eclipse glasses and handheld solar viewers meet the ISO 12312-2 requirements for such products: Rainbow Symphony, American Paper Optics, Thousand Oaks Optical, and TSE 17.
     Welding glass number 14 (or more) is safe, however, most welding helmets do not use that dark of glass. Solar filters from telescopes should be safe, but there is a concern about inexpensive telescope equipment being exposed to multiple minutes of Sun heat may cause difficulties. Other bad ideas include dark sunglasses, exposed film, and thick brown beer bottle bottoms. Do not use your Eclipse Glasses to look through binoculars or telescopes where the magnification of the sunlight has been enhanced and the Eclipse Glasses have not been. It is not worth risking your eyes. Several methods of projection or indirect viewing will be discussed in later Eclipse Corners.
     Some areas will have a horn, siren, or announcement to signify that totality has been reached. Now, it is safe to look at the Sun. Put your glasses and observing devices down and enjoy. This is what we have been waiting for- totality. A total solar eclipse is probably the most spectacular astronomical event that most people will experience in their lives.  -Dan Slais

Join us August 18-21, 2017 for Midnight at Noon, a four day music festival and eclipse viewing event.  Check our our website 

Wednesday, July 12, 2017

Eclipse Corner #6 The Sun and Color in Space


     The Sun has been described as a huge glowing sphere of plasma or ionized gas. Plasma is the fourth state of matter after solid, liquid, and gas. Not seen often on earth, examples of plasma include lightning, fluorescent lighting, and a type of television display panel no longer in production.  
      Zones or layers on the Sun have been detected because of temperature changes. The core cannot be seen, it is inside the photosphere which we see as the surface of the Sun. The chromo-sphere is considered to be an atmosphere and the corona the outer atmosphere. The only time we can see the corona is during a total solar eclipse.
     The astronomical discoveries made through the use of a total solar eclipse are amazing. Isaac Newton published results of his experiments with light in 1672. Using a prism, he refracted sun light into a resolution of its component colors – the complete spectrum. In 1859 chemists Kirchhoff and Bunsen discovered colors released in light by burning gases of different elements. These were the fingerprints of the natural elements. In other words, each element would show its own bright line colors. During a total eclipse in 1868, French astronomer Jules Janssen studied spectral lines of the Sun. A new group of colors was seen indicating a new gas. What was the Sun made of?
     Warren De la Rue got the first photograph of the totally eclipsed Sun in 1860. The photo showed the corona or outer atmosphere of the Sun and flame-like tongues or geysers of gases within the corona. Janssen and British astronomer Norman Lockyer independently studied these prominences. The gas hydrogen was detected by the bright lines displayed, but another unknown gas was seen. Janssen found no element with the same color lines and proposed a new element.                                  



From Tyler Nordgren’s book Sun, Moon, Earth

     Lockyer studied it and named it helium after the Sun god Helios. It would take until 1895 until helium was found on earth. The Sun is 93 million miles away and astronomers are identifying its composition from earth by colored lines it produces.



     Francis Baily, British mathematician and astronomer, and member of the Royal Astronomical Society, saw the 1836 annular eclipse in Scotland.  He reported the solar ring around the Moon’s shadow but also acknowledged the complicated pattern of bright “beads.” These are noticeable just before and after totality of the solar eclipse. Today they are known as “Baily’s Beads.” It is created by the sunlight streaming through the topography of the rugged lunar limb landscape.
     Baily’s observations convey some of the excitement in his moments of the totality in1842 European total solar eclipse. “I was electrified  at the sight of one of the most brilliant and splendid phenomena that can well be imagined. For, at that instant the dark body of the moon was suddenly surrounded with a corona, or kind of bright glory, similar in shape and relative magnitude to that which painters draw round the heads of saints".....  There is more upcoming solar eclipse information in the next Eclipse Corner.  –Dan Slais




 Join us August 18-21 for Midnight at Noon, a four day music festival and eclipse viewing event.  Check out our website at eclipsemissouri2017.com

Wednesday, July 5, 2017

Eclipse Corner #5 Archaeoastronomy

     Archaeoastronomy is the scientific investigation of the processes and practices of ancient peoples relative to their knowledge of the heavenly cosmos. Many cultures have left signs or markings to show ideas for calendars and solstices, the longest and shortest amounts of Sun during the year. Both could be important to an agricultural society. The first day of summer, the summer solstice, the earth is


tilted the maximum 23 ½ degrees toward the sun, our longest day of sun exposure. At the winter solstice, the tilt is 23 ½ degrees away from the Sun, our shortest Sun exposure. Summer solstice is June 21 and Winter solstice is December 21.
     Multiple civilizations world-wide had this understanding of the solstice but where is the evidence? Markers like Stonehenge are key to recognition to what was known. Finding sites with markers, cliff shadows, or petroglyphs (images cut into rock) to tell or show an astronomical event such as a summer solstice might be difficult for a person to find or interpret. After these types of markers were realized at Chaco Canyon, 1977, in the south-west United States, many have been found in North America.

-Slais
     This is a picture of an Anasazi marker in Petrified Forest National Park where a shadow of a rock crosses the petroglyph of the Sun at dawn on June 21 each year. Another petroglyph at Puerco Pueblo is shown to the public near June 21. Robert Preston and his wife have found 76 calendar/solstice markers in Petrified Forest National Park.
     Eclipses are awe-inspiring phenomena. It is no wonder that in many early cultures they were believed to be sacred, depicting fascinating mythology, or thought to be heavenly signs foretelling the future. Eclipse-lore to explain the disappearance of the Sun included ideas of the Sun being eaten, being stolen, and being a time of war and anger. Other cultures see it as a time to unite and settle differences. The ancient Chinese believed that solar eclipses occur when a legendary celestial dragon devours the Sun. It was tradition in ancient China to bang drums and pots and make loud noise during the eclipse to frighten the dragon away. The Inca thought a jaguar was attacking the Sun, the Pomo, an indigenous group from the Northwest US, thought it was a bear, in Vietnam a frog eats the Sun, the Vikings had sky-wolves, and the Korean culture had fire-dogs to attack the Sun. An interesting hypothesis at the Cahokia Mounds is that the solar eclipse allowed an opening to occur to God.                                               


Coronal eclipse petroglyph from Chaco Canyon    www.colorado. edu
Ancient markers showing solar eclipses have been identified as well.
     A famous petroglyph at Piedra del Sol in Chaco Canyon, New Mexico matches the total eclipse there on July 11,1097 when Venus was seen during totality to the upper left and in a time with coronal mass ejections. The amazing part of archaeo-astronomy is that some cultures were thought to be able to calculate when the next lunar or solar eclipse would occur. Modern astronomy did not get to that


point until the 1600’s with understanding of space design and advanced math.      The Eclipse Corner will continue to explain and show more astronomy as we get ready for the August 21, 2017 solar eclipse.  –Dan Slais   

Join us August 18-21, 2017 for Midnight at Noon, a four day music festival and eclipse viewing event.  Check out our website at eclipsemissouri2017.com

Wednesday, June 28, 2017

2017 Eclipse Corner #4 Types of Eclipses


     An eclipse is a blocking of light when one heavenly body moves into the shadow  of another heavenly body. Both the Sun and the Moon get caught in shadows and disappear from view of the earth. A lunar or Moon eclipse occurs in the full moon phase when the Moon is at the nodes or in alignment with the earth-sun plane. The shadow of the earth crosses the Moon creating 3 types of eclipses. The umbra portion of the earth’s shadow is where the direct shadow of the sunlight is blocked. This umbra will produce a total lunar eclipse if the whole moon is in the umbra. If only part of the Moon is in the umbra shadow then it will be a partial lunar eclipse. The penumbra shadow is not the direct shadow and only some of the light is blocked. Much of the time the penumbral eclipse is not noticeable.


-Slais
     A penumbral eclipse is only of academic interest. It is very subtle and hard to observe.


     The Moon went through a penumbral lunar eclipse on February 11.  A lunar eclipse is reflected light from the Sun and presents no danger to the eyes. Because the Earth is much larger than the Moon, the totality portion of a lunar eclipse may block the Moon’s light for more than an hour. The number of lunar eclipses can vary from two to five per year. Because penumbral eclipses are so inconspicuous, most viewers are keeping track of only the umbral eclipses. Those are the partial and total lunar ones which can range from zero to three a year.
     Solar eclipses occur when the moon is in New Moon phase or between the Earth and the Sun. The Moon has to be in the line of the nodes or in alignment with the Sun-Earth plane. Often the alignment will place both the Solar and Lunar eclipse two weeks from each other.  This summer, a partial lunar eclipse is due for much of the world on August  7, but the central US will not see it. Two weeks later on August 21, 2017 will be our Total Solar Eclipse.



     Please observe the small portion of the earth receiving the umbral shadow. The total solar eclipse only covers a 170 mile width band as it moves across the earth. You must be in the right location.

There are three types of Solar eclipses.  A Partial solar eclipse is when we see only part of the Sun blocked out.  A Total Solar Eclipse is when the whole Sun is covered like what we will see in August. The third type is called an Annular Eclipse happens when the Moon is at apogee according to Kepler’s Laws and with a smaller shadow and fits inside the totality of the Sun and cannot produce totality.



     This picture shows Dan Slais as a National Park Ranger in Petrified Forest National Park showing the 2012 partial Eclipse. The method used here is an indirect view through a reflecting telescope on to a poster board.
Next time, Eclipse Corner will look at some Archeoastronomy and solar eclipses.   –Dan Slais

Join us August 18-21, 2017 for Midnight at Noon - a 4-day Music Festival and Eclipse Viewing Event.  For more information visit our website eclipsemissouri2017.com

Eclipse Corner #9 Projection: Pinhole & Optical

    For enjoying the approximately 3 hours of the total eclipse on August 21, one must provide themselves with a way to look at the Sun wit...