Joe Orman's Naked-Eye
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Light Color and Atmospheric Light, Color, and Atmospheric Optics
Light, Color, and Atmospheric Optics Chapter 19 April 28 and 30, 2009 Colors • Sunlight contains all colors (visible spectrum) Wavelength Ranges in µm UV-C: 0.25 - 0.29 UV-B: 0.29 - 0.32 UV-A: 0.32 - 0.38 Visible: 0.38 - 0.75 Near IR: 0.75 - 4 Mid IR: 4 - 8 Longwave IR: 8 - 100 Colors • If object is white then all colors are reflected • If object is red then only red is reflected and all others are absorbed From Malm (1999). Introduction to Visibility Blue Skies and Hazy days • Selective scattering – Scattering depends on wavelength of light • Rayleigh scattering – Very small particles, gases • Mie scattering – Particles the size of wavelength of visible light • Blue haze • Some particles from plants: terpenes, α- pinene Blue Ridge Mountains • Blue haze caused by scattering of blue light by fine particles Creppyuscular Rays • Scattering of sunlight by dust and haze produces white bands Selective Scattering: Sunset • Notice the effects of scattering on color as sunlight penetrates into the atmosphere Twinkling, Twilight, and the Green Flash • Light that travels from a less dense to a more dense medium loses speed and bends toward the normal, while light that enters a less dense medium increase speed and bends away from the normal. • Apparent position, scintillation, and green flash all depend of density variations in the athtmosphere • Scintillation also indicates the amount of turbulence in the atmosphere Bending of Light Paths from Atmosphere Green Flash • Green flash at top may be seen under circumstances of very cold (dense) air near the surface rapidly changing to warmer (less dense) air aloft Mirages •Miraggyges are caused by refraction of light due to strong density differences in atmospheric layers usually caused by strong temperature differences. -
Starry Starry Night Part 1
Starry Starry Night Part 1 DO NOT WRITE ON THIS PORTION OF THE TEST 1. If a lunar eclipse occurs tonight, when is the soonest a solar eclipse can occur? A) Tomorrow B) In two weeks C) In six months D) In one year 2. The visible surface of the Sun is called its A) corona B) photosphere C) chromosphere D) atmosphere 3. Which moon in the Solar System has lakes and rivers on it: A) Triton B) Charon C) Titan D) Europa 4. The sixth planet from the Sun is: A) Mars B) Jupiter C) Saturn D) Uranus 5. The orbits of the planets and dwarf planets around the Sun are in the shape of: A) An eclipse B) A circle C) An ellipse D) None of the above 6. True or False: During the summer and winter solstices, nighttime and daytime are of equal length. 7. The diameter of the observable universe is estimated to be A) 93 billion miles B) 93 billion astronomical units C) 93 billion light years D) 93 trillion miles 8. Asteroids in the same orbit as Jupiter -- in front and behind it -- are called: A) Greeks B) Centaurs C) Trojans D) Kuiper Belt Objects 9. Saturn's rings are made mostly of: A) Methane ice B) Water ice C) Ammonia ice D) Ice cream 10. The highest volcano in the Solar System is on: A) Earth B) Venus C) Mars D) Io 11. The area in the Solar System just beyond the orbit of Neptune populated by icy bodies is called A) The asteroid belt B) The Oort cloud C) The Kuiper Belt D) None of the above 12. -
Conspicuity of High-Visibility Safety Apparel During Civil Twilight
UMTRI-2006-13 JUNE 2006 CONSPICUITY OF HIGH-VISIBILITY SAFETY APPAREL DURING CIVIL TWILIGHT JAMES R. SAYER MARY LYNN MEFFORD CONSPICUITY OF HIGH-VISIBILITY SAFETY APPAREL DURING CIVIL TWILIGHT James R. Sayer Mary Lynn Mefford The University of Michigan Transportation Research Institute Ann Arbor, MI 48109-2150 U.S.A. Report No. UMTRI-2006-13 June 2006 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. UMTRI-2006-13 4. Title and Subtitle 5. Report Date Conspicuity of High-Visibility Safety Apparel During Civil June 2006 Twilight 6. Performing Organization Code 302753 7. Author(s) 8. Performing Organization Report No. Sayer, J.R. and Mefford, M.L. UMTRI-2006-13 9. Performing Organization Name and Address 10. Work Unit no. (TRAIS) The University of Michigan Transportation Research Institute 11. Contract or Grant No. 2901 Baxter Road Ann Arbor, Michigan 48109-2150 U.S.A. 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered The University of Michigan Industry Affiliation Program for 14. Sponsoring Agency Code Human Factors in Transportation Safety 15. Supplementary Notes The Affiliation Program currently includes Alps Automotive/Alpine Electronics, Autoliv, Avery Dennison, Bendix, BMW, Bosch, Com-Corp Industries, DaimlerChrysler, DBM Reflex, Decoma Autosystems, Denso, Federal-Mogul, Ford, GE, General Motors, Gentex, Grote Industries, Guide Corporation, Hella, Honda, Ichikoh Industries, Koito Manufacturing, Lang- Mekra North America, Magna Donnelly, Muth, Nissan, North American Lighting, Northrop Grumman, OSRAM Sylvania, Philips Lighting, Renault, Schefenacker International, Sisecam, SL Corporation, Stanley Electric, Toyota Technical Center, USA, Truck-Lite, Valeo, Visteon, 3M Personal Safety Products and 3M Traffic Safety Systems Information about the Affiliation Program is available at: http://www.umich.edu/~industry 16. -
RADIAL VELOCITIES in the ZODIACAL DUST CLOUD
A SURVEY OF RADIAL VELOCITIES in the ZODIACAL DUST CLOUD Brian Harold May Astrophysics Group Department of Physics Imperial College London Thesis submitted for the Degree of Doctor of Philosophy to Imperial College of Science, Technology and Medicine London · 2007 · 2 Abstract This thesis documents the building of a pressure-scanned Fabry-Perot Spectrometer, equipped with a photomultiplier and pulse-counting electronics, and its deployment at the Observatorio del Teide at Izaña in Tenerife, at an altitude of 7,700 feet (2567 m), for the purpose of recording high-resolution spectra of the Zodiacal Light. The aim was to achieve the first systematic mapping of the MgI absorption line in the Night Sky, as a function of position in heliocentric coordinates, covering especially the plane of the ecliptic, for a wide variety of elongations from the Sun. More than 250 scans of both morning and evening Zodiacal Light were obtained, in two observing periods – September-October 1971, and April 1972. The scans, as expected, showed profiles modified by components variously Doppler-shifted with respect to the unshifted shape seen in daylight. Unexpectedly, MgI emission was also discovered. These observations covered for the first time a span of elongations from 25º East, through 180º (the Gegenschein), to 27º West, and recorded average shifts of up to six tenths of an angstrom, corresponding to a maximum radial velocity relative to the Earth of about 40 km/s. The set of spectra obtained is in this thesis compared with predictions made from a number of different models of a dust cloud, assuming various distributions of dust density as a function of position and particle size, and differing assumptions about their speed and direction. -
Why Doesn't the Sky Turn Green?
Why Doesn't The Sky Turn Green? Rushi Shah 09 November 2015 I was leafing through the US Army Corps of Engineers' Manual on Remote Sensing and learned about how Rayleigh scattering creates blue skies during the day and redish-orange sunsets. Well, everybody knows about blue skies and red sunsets, was the title just click-bait, you ask? No, but I'll get to that. 1 The Basics of Rayleigh Scattering Let's start with this whole Rayleigh scattering thing. Basically the idea is that particles in the atmosphere (like Oxygen and Nitrogen particles) scatter rays of light as they enter the atmosphere. How much the light is scattered is heavily dependent on the wavelength of the light. Remember how ROY-G-BIV represents the colors of the rainbow (and thus the spectrum of visible light)? Well that spectrum of light starts with long wavelength rays (reds, oranges, and yellows) and ends with short wavelength rays (blues, indigos, and violets). 1 The amount of light that is scattered (denoted with the variable I) is highly inversely proportional to the wavelength of the light (denoted with the greek letter ). Put simply, as the wavelength goes down, the light waves are scattered more quickly. 1 I / λ4 When sunlight hits the earth directly during mid-day, it travels through a small amount of atmosphere, and thus we see the wavelengths of light that are immediately scattered. Based on the equation above, the blues, indigos, and violets would be scattered first (and they blend together into the blue sky we see). As the sun sets, it goes through more and more particles to reach us. -
Atmospheric Effects Are Looking Up
Atmospheric Effects are Looking Up OASI Workshop 21st May 2018 by Olaf Kirchner Ever seen one of these ? OK, so how about one of these? Atmospheric Effects - caused by sun- or moonlight interacting with liquid water or ice in the air - surprisingly common - always beautiful and one or several phenomena may be seen at the same time - can be in-your-face obvious or very subtle, and ... - ... span the entire sky - a challenge to photograph - very complicated theoretical explanations Effects caused by Liquid Water Droplets - rainbows - glories, Heiligenschein and the Spectre of the Brocken - aureoles / coronae - nacreous / iridescent / Mother-of-Pearl clouds Rainbow Rainbow Ray paths for primary rainbow Ray paths through a spherical water drop Ray paths for secondary rainbow Secondary Rainbow Secondary rainbow Alexander’s Band Supernumerary rainbow Primary rainbow Rainbow Gap in cloud behind observer = partial rainbow Rainbow in spray, Geneva Jet d’Eau Supernumerary Rainbow Interference colours from different lengths of light path Rainbow Circular rainbow seen from an aircraft Rainbows don’t reflect ... Glory Colourful diffraction rings centred on the antisolar point, caused by reflection from spherical droplets Glory ... i.e. centred on where the shadow of your head would be! Brockengespenst = Spectre of the Brocken Taken against fog from Golden Gate Bridge Brocken (1142 m) . Highest point in the Harz mountains Heiligenschein = Halo Antisolar point in hydrothermal steam ... scary stuff Heiligenschein ... i.e. a glory centred on your head -
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. -
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. -
Download This Article in PDF Format
A&A 598, A40 (2017) Astronomy DOI: 10.1051/0004-6361/201629659 & c ESO 2017 Astrophysics Separation and confirmation of showers? L. Neslušan1 and M. Hajduková, Jr.2 1 Astronomical Institute, Slovak Academy of Sciences, 05960 Tatranska Lomnica, Slovak Republic e-mail: [email protected] 2 Astronomical Institute, Slovak Academy of Sciences, Dubravska cesta 9, 84504 Bratislava, Slovak Republic e-mail: [email protected] Received 6 September 2016 / Accepted 30 October 2016 ABSTRACT Aims. Using IAU MDC photographic, IAU MDC CAMS video, SonotaCo video, and EDMOND video databases, we aim to separate all provable annual meteor showers from each of these databases. We intend to reveal the problems inherent in this procedure and answer the question whether the databases are complete and the methods of separation used are reliable. We aim to evaluate the statistical significance of each separated shower. In this respect, we intend to give a list of reliably separated showers rather than a list of the maximum possible number of showers. Methods. To separate the showers, we simultaneously used two methods. The use of two methods enables us to compare their results, and this can indicate the reliability of the methods. To evaluate the statistical significance, we suggest a new method based on the ideas of the break-point method. Results. We give a compilation of the showers from all four databases using both methods. Using the first (second) method, we separated 107 (133) showers, which are in at least one of the databases used. These relatively low numbers are a consequence of discarding any candidate shower with a poor statistical significance. -
Atmospheric Phenomena by Feist
Atmospheric optical phenomena An introductory guide by Mike Feist Effects caused by water droplets— rainbows and coronae The most well known optical sky effect is the rainbow. This, as most people know, sometimes occurs when the Sun is out and it is raining. To see a rainbow you must stand with your back to the Sun with the raindrops in front of you. It does not have to be raining where you are standing but in the direction that you are looking. The arc of the primary (main) bow is centred on the antisolar point, the spot directly oppo- site the Sun, and has a radius of 42°. The antisolar point is actually centred on the shadow of your head. If the Sun is rising or setting and therefore on the horizon, the primary rainbow will be a complete semi- circle and the top will be 42° up in the sky. If, on the other hand, the Sun is 42° up in the sky, the primary bow will be on the horizon, the top just rising or setting. Con- ventionally the rainbow is said to have John Constable. Hampstead Heath with a Rainbow (1836). seven colours but all we need to remember seen in the spray near waterfalls and artifi- ous forms but with a six-sided shape. They is that, in the primary bow, the red is on cial rainbows can be made using a garden may be as flat hexagonal plates or long the outside and the blue on the inside. Out- hose. Rainbows are one of the easiest opti- hexagonal prisms or as a combination of side the primary bow sometimes there is cal effects to photograph although they the two. -
Meteor Shower Detection with Density-Based Clustering
Meteor Shower Detection with Density-Based Clustering Glenn Sugar1*, Althea Moorhead2, Peter Brown3, and William Cooke2 1Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 2NASA Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, AL, 35812 3Department of Physics and Astronomy, The University of Western Ontario, London N6A3K7, Canada *Corresponding author, E-mail: [email protected] Abstract We present a new method to detect meteor showers using the Density-Based Spatial Clustering of Applications with Noise algorithm (DBSCAN; Ester et al. 1996). DBSCAN is a modern cluster detection algorithm that is well suited to the problem of extracting meteor showers from all-sky camera data because of its ability to efficiently extract clusters of different shapes and sizes from large datasets. We apply this shower detection algorithm on a dataset that contains 25,885 meteor trajectories and orbits obtained from the NASA All-Sky Fireball Network and the Southern Ontario Meteor Network (SOMN). Using a distance metric based on solar longitude, geocentric velocity, and Sun-centered ecliptic radiant, we find 25 strong cluster detections and 6 weak detections in the data, all of which are good matches to known showers. We include measurement errors in our analysis to quantify the reliability of cluster occurrence and the probability that each meteor belongs to a given cluster. We validate our method through false positive/negative analysis and with a comparison to an established shower detection algorithm. 1. Introduction A meteor shower and its stream is implicitly defined to be a group of meteoroids moving in similar orbits sharing a common parentage. -
Atmospheric Optics
53 Atmospheric Optics Craig F. Bohren Pennsylvania State University, Department of Meteorology, University Park, Pennsylvania, USA Phone: (814) 466-6264; Fax: (814) 865-3663; e-mail: [email protected] Abstract Colors of the sky and colored displays in the sky are mostly a consequence of selective scattering by molecules or particles, absorption usually being irrelevant. Molecular scattering selective by wavelength – incident sunlight of some wavelengths being scattered more than others – but the same in any direction at all wavelengths gives rise to the blue of the sky and the red of sunsets and sunrises. Scattering by particles selective by direction – different in different directions at a given wavelength – gives rise to rainbows, coronas, iridescent clouds, the glory, sun dogs, halos, and other ice-crystal displays. The size distribution of these particles and their shapes determine what is observed, water droplets and ice crystals, for example, resulting in distinct displays. To understand the variation and color and brightness of the sky as well as the brightness of clouds requires coming to grips with multiple scattering: scatterers in an ensemble are illuminated by incident sunlight and by the scattered light from each other. The optical properties of an ensemble are not necessarily those of its individual members. Mirages are a consequence of the spatial variation of coherent scattering (refraction) by air molecules, whereas the green flash owes its existence to both coherent scattering by molecules and incoherent scattering