Roadmap #84 Hardly Any Light ⏤ Which Means Much Slower Shutter Speeds As Well
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@ SOUTHWEST FOREST SERVICE Forest and R U. S.DEPARTMENT OF AGRICULTURE P.0. BOX 245, BERKELEY, CALIFORNIA 94701 Experime Computation of times of sunrise, sunset, and twilight in or near mountainous terrain Bill 6. Ryan Times of sunrise and sunset at specific mountain- ous locations often are important influences on for- estry operations. The change of heating of slopes and terrain at sunrise and sunset affects temperature, air density, and wind. The times of the changes in heat- ing are related to the times of reversal of slope and valley flows, surfacing of strong winds aloft, and the USDA Forest Service penetration inland of the sea breeze. The times when Research NO& PSW- 322 these meteorological reactions occur must be known 1977 if we are to predict fire behavior, smolce dispersion and trajectory, fallout patterns of airborne seeding and spraying, and prescribed burn results. ICnowledge of times of different levels of illumination, such as the beginning and ending of twilight, is necessary for scheduling operations or recreational endeavors that require natural light. The times of sunrise, sunset, and twilight at any particular location depend on such factors as latitude, longitude, time of year, elevation, and heights of the surrounding terrain. Use of the tables (such as The 1 Air Almanac1) to determine times is inconvenient Ryan, Bill C. because each table is applicable to only one location. 1977. Computation of times of sunrise, sunset, and hvilight in or near mountainous tersain. USDA Different tables are needed for each location and Forest Serv. Res. Note PSW-322, 4 p. Pacific corrections must then be made to the tables to ac- Southwest Forest and Range Exp. -
Soaring Weather
Chapter 16 SOARING WEATHER While horse racing may be the "Sport of Kings," of the craft depends on the weather and the skill soaring may be considered the "King of Sports." of the pilot. Forward thrust comes from gliding Soaring bears the relationship to flying that sailing downward relative to the air the same as thrust bears to power boating. Soaring has made notable is developed in a power-off glide by a conven contributions to meteorology. For example, soar tional aircraft. Therefore, to gain or maintain ing pilots have probed thunderstorms and moun altitude, the soaring pilot must rely on upward tain waves with findings that have made flying motion of the air. safer for all pilots. However, soaring is primarily To a sailplane pilot, "lift" means the rate of recreational. climb he can achieve in an up-current, while "sink" A sailplane must have auxiliary power to be denotes his rate of descent in a downdraft or in come airborne such as a winch, a ground tow, or neutral air. "Zero sink" means that upward cur a tow by a powered aircraft. Once the sailcraft is rents are just strong enough to enable him to hold airborne and the tow cable released, performance altitude but not to climb. Sailplanes are highly 171 r efficient machines; a sink rate of a mere 2 feet per second. There is no point in trying to soar until second provides an airspeed of about 40 knots, and weather conditions favor vertical speeds greater a sink rate of 6 feet per second gives an airspeed than the minimum sink rate of the aircraft. -
Chapter 19 the Almanacs
CHAPTER 19 THE ALMANACS PURPOSE OF ALMANACS 1900. Introduction The Air Almanac was originally intended for air navigators, but is used today mostly by a segment of the Celestial navigation requires accurate predictions of the maritime community. In general, the information is similar to geographic positions of the celestial bodies observed. These the Nautical Almanac, but is given to a precision of 1' of arc predictions are available from three almanacs published and 1 second of time, at intervals of 10 minutes (values for annually by the United States Naval Observatory and H. M. the Sun and Aries are given to a precision of 0.1'). This Nautical Almanac Office, Royal Greenwich Observatory. publication is suitable for ordinary navigation at sea, but The Astronomical Almanac precisely tabulates celestial lacks the precision of the Nautical Almanac, and provides data for the exacting requirements found in several scientific GHA and declination for only the 57 commonly used fields. Its precision is far greater than that required by navigation stars. celestial navigation. Even if the Astronomical Almanac is The Multi-Year Interactive Computer Almanac used for celestial navigation, it will not necessarily result in (MICA) is a computerized almanac produced by the U.S. more accurate fixes due to the limitations of other aspects of Naval Observatory. This and other web-based calculators are the celestial navigation process. available from: http://aa.usno.navy.mil. The Navy’s The Nautical Almanac contains the astronomical STELLA program, found aboard all seagoing naval vessels, information specifically needed by marine navigators. contains an interactive almanac as well. -
How the Sun Paints the Sky the Generation of Its Colour and Luminosity Bob Fosbury European Southern Observatory and University College London
How the Sun Paints the Sky The generation of its colour and luminosity Bob Fosbury European Southern Observatory and University College London Introduction: the 19th century context — science and painting The appearance of a brilliantly clear night sky must surely have stimulated the curiosity of our earliest ancestors and provided them with the foundation upon which their descendants built the entire edifice of science. This is a conclusion that would be dramatically affirmed if any one of us were to look upwards in clear weather from a location that is not polluted by artificial light: an increasingly rare possibility now, but one that provides a welcome regeneration of the sense of wonder. What happened when our ancient ancestors gazed instead at the sky in daylight or twilight? It is difficult to gauge from written evidence as there was such variation in the language of description among different cultures (see “Sky in a bottle” by Peter Pesic. MIT Press, 2005. ISBN 0-262-16234-2). The blue colour of a cloudless sky was described in a remarkable variety of language, but the question of its cause most often remained in the realm of a superior being. Its nature did concern the Greek philosophers but they appeared to describe surfaces and objects in the language of texture rather than colour: they did not have a word for blue. It was only during the last millennium that thinkers really tried to get to grips with the problem, with Leonardo da Vinci, Isaac Newton and Johann Wolfgang von Goethe all applying themselves. It was not easy however, and no real progress was made until the mid-19th century when there was a focus of the greatest scientific minds of the time on the problem of both the colour and the what was then the novel property of polarisation of the light. -
Good Morning, Good Afternoon, and Good Evening to All of Our Participants Around the World
>>>Good morning, good afternoon, and good evening to all of our participants around the world. Welcome to this Webinar sponsored by the international forum for investor education, IFIE and America's chapter of how an investor's complaint can be used to further investor educational goals. You will be hearing from two presenters today, Kattia Castro Cruz and Pierino Stucchi. Before we introduce Kattia Castro Cruz as your moderator I want to explain how the Q&A answer will work. During the question period, to ask a question type the name of your organization and your question into the question box on your Webinar dashboard. This is located towards the bottom of the screen. We often have more questions than we have time to answer. We will try to answer all of the questions that we receive through the Webinar or we will post them after the Webinar event. Thank you again, and I will ask our facilitator leader, Kattia Castro Cruz, to take over. >> Thank you, Katherine, good morning, good afternoon, and good night to all the participants around the world. Welcome to this Webinar that is sponsored by the international forum for investor education IFIE and the America's chapter. Today we have two conferences, and we will have time for questions and answers at the end of the presentation. During the session of questions and answers, to make a question, just put your name, type your name into, and your organization name and then you will have time at the end. It's on the bottom of the right hand screen. -
Sky Watch Heard Most Weekdays on WFWM, FSU's Public Supported
Night Highlights – Dec.2014 through Dec.2015 by Dr. Bob Doyle, Frostburg State Planetarium Dr. Doyle’s email is: [email protected]: His office phone number is (301) 687-7799 MOON – Earth’s companion both orbits Earth and rotates in 27.32 E. days so one side of moon always faces Earth (while other side is turned away from us). Moon’s cycle of lighted shapes (phases) lasts 29.53 E. days, as the phases also depend on direction of sun (appears to move 30 degrees eastward each month along zodiac). The moon is seen about 13 days growing in the evening from a slender crescent ( ) ) to Full, followed by an equal time shrinking (mainly seen in the a.m. sky) and then 3 days hidden in sun’s glare. Key Moon Phases (D) moon ½ full in evening (best for crater & mountain viewing ) & (O) full moon (see all lava plains) (Dec. ’14, 6 -O, 28 – D)) // (Jan. ’15, 4 - O, 26 - D), // (Feb. ’15, 3 – O, 25 - D) // (Mar. 5 – O, 27 – D) (Apr. 4 – O, 25 – D), // ( May 3 – O, 25 - D) // (Jun., 2- O, 27 – D)) // (Jul., 1 – O, 24 –D, 31 –O (Blue Moon)) (Aug., 22 – D, 29 – O) // (Sep., 20 – D, 27 – O (Harvest Moon)) // (Oct. 20 – D, 27 – O (Hunters’ Moon)) // (Nov., 19 – D, 25 – O) // (Dec., 18 – D, 25 – O (Long Night Moon)) (D = ½ full, O = full) THE 5 BRIGHT PLANETS (Mercury, Venus, Mars, Jupiter & Saturn): Uranus, Neptune are much dimmer. When high above horizon, planets appear as points of light that shine steadily. -
The Blue Hours Dusk, Early September, Just Beneath the Arctic
The Blue Hours Dusk, early September, just beneath the Arctic Circle, by a tideline glacier in East Greenland. The cusp of the seasons, the cusp of the globe, the cusp of the land, and the day’s cusp too: twilight, the blue hours. At this latitude, at this time of year, dusk lasts for two or three hours. We have returned from a long mountain day: pitched climbing up steep slabs and over snow slopes to a towered summit, from which height we could see the great inland ice-cap itself. Then down, late in the day, the darkness thickening around us, and the sun dropping fast behind the western peaks. So we sit together back at camp as the last light gathers on the water of the fjord, on icebergs, on the quartz seams in the white boulder-field above our tents. Twilight specifies the landscape in this way – but it also disperses it. Relations between objects are loosened, such that shape-shifts occur. Just before full night falls, and the aurora borealis begins, a powerful hallucination occurs. My tired eyes start to see every pale stone around our tent not as boulder but as bear, polar bear, pure bear, crouched for the spring. Across the Northern hemisphere, twilight is known as the trickster-time: breeder of delusion, feeder of fantasies, zone of becomings. In Greek, dusk is called lykophos, ‘wolf-light’. In Austria, too, it is Wolflicht. In French it is the phase entre chien et loup, ‘between dog and wolf’: the time when, as Chrystel Lebas has written, ‘it is nearly impossible to tell the difference between the howling sound coming from the two animals, when the domestic and familiar transform into the wild.’ I do not know the Greenlandic word for dusk, but perhaps it would translate as ‘bear-light’. -
The Golden Hour Refers to the Hour Before Sunset and After Sunrise
TheThe GoldenGolden HourHour The Golden Hour refers to the hour before sunset and after sunrise. Photographers agree that some of the very best times of day to take photos are during these hours. During the Golden Hours, the atmosphere is often permeated with breathtaking light that adds ambiance and interest to any scene. There can be spectacular variations of colors and hues ranging from subtle to dramatic. Even simple subjects take on an added glow. During the Golden Hours, take photos when the opportunity presents itself because light changes quickly and then fades away. 07:14:09 a.m. 07:15:48 a.m. Photographed about 60 seconds after previous photo. The look of a scene can vary greatly when taken at different times of the day. Scene photographed midday Scene photographed early morning SampleSample GoldenGolden HourHour photosphotos Top Tips for taking photos during the Golden Hours Arrive on the scene early to take test shots and adjust camera settings. Set camera to matrix or center-weighted metering. Use small apertures for maximizing depth-of-field. Select the lowest possible ISO. Set white balance to daylight or sunny day. When lighting is low, use a tripod with either a timed shutter release (self-timer) or a shutter release cable or remote. Taking photos during the Golden Hours When photographing the sun Don't stare into the sun, or hold the camera lens towards it for a very long time. Meter for the sky but don't include the sun itself. Composition tips: The horizon line should be above or below the center of the scene. -
Excerpts from Dusk of Dawn: an Essay Toward an Autobiography Of
DUSK OF DAWN An Essay Toward an Autobiography of a Race Concept W. E. B. Du Bois Series Editor, Henry Louis Gates, Jr. Introduction by K. Anthony Appiah OXFORD UNIVERSITY PRESS Contents SERIES INTRODUCTION: THE BLACK LETTERS ON THE SIGN xi INTRODUCTION xxv APOLOGY xxxiii I. THEPLOT 1 II. A NEW ENGLAND BOY AND RECONSTRUCTION 4 III. EDUCATION IN THE LAST DECADES OF THE NINETEENTH CENTURY 13 IV. SCIENCE AND EMPIRE 26 V. THE CONCEPT OF RACE 49 VI. THE WHITE WORLD 68 VII. THE COLORED WORLD WITHIN 88 VIII. PROPAGANDA AND WORLD WAR 111 IX. REVOLUTION 134 INDEX 163 WILLIAM EDWARD BURGHARDT DUBOIS: A CHRONOLOGY 171 SELECTED BIBLIOGRAPHY 179 ix CHAPTER VII The Colored World Within Not only do white men but also colored men forget the facts of the Negro's dou ble environment. The Negro American has for his environment not only the white surrounding world, but also, and touching him usually much more nearly and compellingly, is the environment furnished by his own colored group. There are exceptions, of course, but this is the rule. The American Negro, therefore, is surrounded and conditioned by the concept which he has of white people and he is treated in accordance with the concept they have of him. On the other hand, so far as his own people are concerned, he is in direct contact with individuals and facts. He fits into this environment more or less willingly. It gives him a social world and mental peace. On the other hand and especially if in education and ambition and income he is above the average culture of his group, he is often resentful of its environilcg power; partly because he does not recognize its power and partly because he is determined to consider himself part of the white group from which, in fact, he is excluded. -
Exploring Solar Cycle Influences on Polar Plasma Convection
Comparison of Terrestrial and Martian TEC at Dawn and Dusk during Solstices Angeline G. Burrell1 Beatriz Sanchez-Cano2, Mark Lester2, Russell Stoneback1, Olivier Witasse3, Marco Cartacci4 1Center for Space Sciences, University of Texas at Dallas 2Radio and Space Plasma Physics, University of Leicester 3European Space Agency, ESTEC – Scientific Support Office 4Istituto Nazionale di Astrofisica, Istituto di Astrofisica e Planetologia Spaziali 52nd ESLAB Symposium Outline • Motivation • Data and analysis – TEC sources – Data selection – Linear fitting • Results – Martian variations – Terrestrial variations – Similarities and differences • Conclusions Motivation • The Earth and Mars are arguably the most similar of the solar planets - They are both inner, rocky planets - They have similar axial tilts - They both have ionospheres that are formed primarily through EUV and X- ray radiation • Planetary differences can provide physical insights Total Electron Content (TEC) • The Global Positioning System • The Mars Advanced Radar for (GPS) measures TEC globally Subsurface and Ionosphere using a network of satellites and Sounding (MARSIS) measures ground receivers the TEC between the Martian • MIT Haystack provides calibrated surface and Mars Express TEC measurements • Mars Express has an inclination - Available from 1999 onward of 86.9˚ and a period of 7h, - Includes all open ground and allowing observations of all space-based sources locations and times - Specified with a 1˚ latitude by 1˚ • TEC is available for solar zenith longitude resolution with error estimates angles (SZA) greater than 75˚ Picardi and Sorge (2000), In: Proc. SPIE. Eighth International Rideout and Coster (2006) doi:10.1007/s10291-006-0029-5, 2006. Conference on Ground Penetrating Radar, vol. 4084, pp. 624–629. -
Planit! User Guide
ALL-IN-ONE PLANNING APP FOR LANDSCAPE PHOTOGRAPHERS QUICK USER GUIDES The Sun and the Moon Rise and Set The Rise and Set page shows the 1 time of the sunrise, sunset, moonrise, and moonset on a day as A sunrise always happens before a The azimuth of the Sun or the well as their azimuth. Moon is shown as thick color sunset on the same day. However, on lines on the map . some days, the moonset could take place before the moonrise within the Confused about which line same day. On those days, we might 3 means what? Just look at the show either the next day’s moonset or colors of the icons and lines. the previous day’s moonrise Within the app, everything depending on the current time. In any related to the Sun is in orange. case, the left one is always moonrise Everything related to the Moon and the right one is always moonset. is in blue. Sunrise: a lighter orange Sunset: a darker orange Moonrise: a lighter blue 2 Moonset: a darker blue 4 You may see a little superscript “+1” or “1-” to some of the moonrise or moonset times. The “+1” or “1-” sign means the event happens on the next day or the previous day, respectively. Perpetual Day and Perpetual Night This is a very short day ( If further north, there is no Sometimes there is no sunrise only 2 hours) in Iceland. sunrise or sunset. or sunset for a given day. It is called the perpetual day when the Sun never sets, or perpetual night when the Sun never rises. -
Here's Some Ideas
On that “Perfect Moment.” “Sometimes there’s that perfect moment when the crowd, the music, the energy of the room come together in a way that brings me to tears” John Legend. Covid-19 Safety Concerns The LCC executive advises against heading out right now. By staying home, you are protecting your life as well as the lives of others. If you are out and about though, remember to keep 2 meters apart, watch what you touch and wash your hands often (yeah, I know- I sound like your mom…). May 2020 Theme- Blue Hour. Definition: The blue hour is the period of twilight in the morning or evening, when the Sun is at a significant depth below the horizon and residual, indirect sunlight takes on a predominantly blue shade that is different from the blue shade visible during most of the day, which is caused by Rayleigh scattering. The requirement to have taken the picture at the Blue Hour has been suspended. Feel free to use post-production techniques in your editing software to add in the “Cool Blues.” Take out some of your old, Blue Hour images and work at enhancing them to best suit this theme. Here’s some ideas: Tim Shields critiques a number of pictures to describe what makes a great Blue Hour shot. Tim does a good job describing what works and what doesn’t. The video is about 15 minutes long but only the first 7 minutes is on the Blue Hour. Tim also touches on how some of the contributed photos could have been enhanced through simple steps in post production.