DOCSLIB.ORG

Finding the Celestial Poles

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Finding the Celestial Poles PHYS 3380 - Astronomy Finding the Celestial Poles You can always find north using the North Star. Polaris can be found using the big dipper. Draw a line through the two “pointer” stars at the end of the big dipper and follow it upwards from the dipper about four outstretched hand’s width. The big dipper is circumpolar in the US so is always above the horizon. The south celestial pole can be found using the Southern Cross. There is no “South Star” PHYS 3380 - Astronomy The Big and Little Dippers PHYS 3380 - Astronomy Motion of the Night Sky Animation PHYS 3380 - Astronomy a The angle a between the horizon and Polaris is the latitude of the observer. If Dallas is at 33º latitude, where is Polaris in the sky? Where is it at the Equator? PHYS 3380 - Astronomy Angular Size Distances in the sky measured by angular distance: Minute of arc = 1/60th of a degree Second of arc = 1/3600th of a degree Angular diameter - angular distance from one side of an object to the other PHYS 3380 - Astronomy Revolution Earth travels around the sun (orbits) once per year in the same direction it rotates. Its orbit is not quite a perfect circle - it is elliptical. The location in the orbit of the minimum and maximum distances from the Sun are called perihelion and aphelion. The plane of the orbit is called the ecliptic. PHYS 3380 - Astronomy Earth’s Axial Tilt Axial Tilt of the Planets Sun 7.25 (to the Ecliptic) Mercury ~0.01 Venus 177.4 Earth 23.439281 Moon 1.5424 Mars 25.19 Ecliptic Ceres ~4 Plane Jupiter 3.13 Saturn 26.73 Uranus 97.77 Neptune 28.32 Pluto 119.61 The Earth’s axis is currently tilted about 23.5º to the ecliptic. It varies over time between 22º and 25º due the the gravitational forces from Jupiter and the other planets. PHYS 3380 - Astronomy The axis remains at the same tilt angle - pointed at Polaris - throughout the orbit because of conservation of angular momentum. The ecliptic plane is the plane of the Earth’s orbit. Looking from the Earth, it is the apparent path of the Sun (and planets) in the sky. PHYS 3380 - Astronomy The Relationship of the Celestial Equator and the Ecliptic Plane PHYS 3380 - Astronomy The Zodiac The Sun appears to move steadily eastward along the ecliptic, through the constellations of the zodiac. As Earth orbits the Sun, we see the Sun against the background of different zodiac constellations at different times of year. For example, on August 21 the Sun appears to be in the constellation Leo. Defines astral calendar. PHYS 3380 - Astronomy Sun’s Path Through the Zodiac PHYS 3380 - Astronomy Celestial The apparent Sphere Sphere of the sky Celestial The points Poles about which the celestial sphere appears to rotate Celestial Projection of Equator the Earth’s equator on the celestial sphere Ecliptic Apparent annual path of the sun on the celestial sphere PHYS 3380 - Astronomy Coordinate Systems Geographic Celestial Latitude - lines of latitude parallel to Declination - lines of declination parallel to Earth’s equator - labeled north or south celestial equator - labeled positive or relative to equator - from 90º N to 90º S negative relative to celestial equator - from - 90º to +90º Longitude - lines of longitude extend from North Pole to South Pole - by international Right ascension - lines of right ascension treaty, longitude 0 (the prime meridian) run from north celestial pole to south runs through Greenwich, England celestial pole - by convention 0 runs through spring equinox - measured in hours, minutes and seconds east of spring equinox - one hour is 15º PHYS 3380 - Astronomy PHYS 3380 - Astronomy Local Skies Lines of constant declination cross the sky at different altitudes, depending on your location on Earth. declination line = your latitude - goes through your zenith the altitude of the N or S celestial pole = your latitude PHYS 3380 - Astronomy Local Skies PHYS 3380 - Astronomy Determining latitude Find celestial pole - latitude equal to angular altitude - in northern hemisphere Polaris is within 1º of celestial pole For more precision - use star with known declination - determine angular altitude as it crosses your meridian - imaginary half circle drawn from your horizon due south, through zenith (point directly overhead) to horizon due north - or when star is at its highest altitude in the sky. Ancients used cross- staff or Jacob’s ladder to determine angular altitude. Modern device called a sextant. Sextant PHYS 3380 - Astronomy Vega crosses your meridian in the southern sky at 78º 44’. You know it crosses your meridian at 38º 44’ north of the celestial equator. So the celestial equator must cross your meridian at an altitude of 40º so your latitude is 50º. The formula for latitude is north/south of zenith. Sun can also be used if you know the date and the Sun’s declination on that date. Make sure you understand that north/south refers to the direction of the star from zenith at your viewing location. PHYS 3380 - Astronomy Annual Motion of the Sun The R.A. of the Sun… increases about 2 hours per month The Declination of the Sun… varies between –23.5º and +23.5º PHYS 3380 - Astronomy Celestial Navigation Determining longitude Need to compare current positions of objects in your sky with positions at known longitude - Greenwich (0º Longitude). For instance - use sundial to determine local solar time is 3:00 PM. If time at Greenwich is 1:00 PM, you are two hours east of Greenwich and your longitude is 15º X 2 = 30º East Longitude. Accurate determination of longitude required invention of clock that could remain accurate on a rocking ship. By early 1700s, considered so important, British government offered large monetary prize for the solution - claimed by John Harrison in 1761 after 31 years of work. Clock lost only 5 seconds during a 9-week voyage. Harrison fought government for several years, finally begin awarded part of the prize in 1773 when he was 80 years old, after appealing to King George III. PHYS 3380 - Astronomy Seasons occur because even though the Earth's axis remains pointed toward Polaris throughout the year, the orientation of the axis relative to the Sun changes as the Earth orbits the Sun. Around the time of the summer solstice, the Northern Hemisphere has summer because it is tipped toward the Sun, and the Southern Hemisphere has winter because it is tipped away from the Sun. The situation is reversed around the time of the winter solstice when the Northern Hemisphere has winter and the Southern Hemisphere has summer. At the equinoxes, both hemispheres receive equal amounts of light. PHYS 3380 - Astronomy Why Does Flux Sunlight Vary Animation PHYS 3380 - Astronomy Antarctica June 21 December 21 PHYS 3380 - Astronomy In the summer hemisphere, the sun follows a longer and higher path. The sunlight is more intense - more direct and more concentrated. In the winter hemisphere, the sun follows a shorter and lower path. The sunlight is less direct and less intense. Why are the warmest days one to two months after summer solstice? PHYS 3380 - Astronomy Sun’s Altitude vs Latitude and Season Animation PHYS 3380 - Astronomy The next few slides are from a paper I wrote about the seasonal, hemispherical, and solar cycle variation in the ionosphere due to variations in solar irradiance and output. You are not expected to remember this – I just wanted to show you some applied science associated with what you have learned about seasonal effects. I will teach you more about the sun, solar output, and the solar cycle when we talk about the sun. PHYS 3380 - Astronomy The Earth’s ionosphere is produced by solar extreme ultraviolet radiation. The amount of radiation that reaches the ionosphere and produces ionization is dependent on the solar zenith angle (the angle between the zenith and the center of the Sun's disc) which in turn varies with season. Solar output itself varies with solar cycle, and solar rotation. The top panel shows the daily average of the ionospheric density measured by the Defense Meteorological Satellite Program spacecraft at ~830 km. Red is in the northern hemisphere and black is in the southern hemisphere. The bottom panel shows the solar zenith angle. It shows the clear seasonal variation (and the solar cycle variation). [Anderson and Hawkins, 2015] PHYS 3380 - Astronomy The ionospheric density (blue in the top panel) is highly correlated with the 11-year solar cycle. Solar output is measured by E10.7 (in green). The composition is also very highly correlated PHYS 3380 - Astronomy There is also high degree of variation due to the 27-day solar rotation. Different portions of the sun produce more or less output. Cross correlation coefficients between ionospheric density and solar output (E10.7) show a 26-day variation over several months. The x-axis shows an applied time delay between the measurements. The one less day is because the Earth is orbiting the Sun as the Sun rotates. PHYS 3380 - Astronomy Empirical Orthogonal Function (EOF) analysis, closely related to Principal Components Analysis, can pull out the various dependencies of data variation. This shows the EOFs (or eigenvectors of the covariance matrix) for the first two principal components (which capture over 95% of the variation) plotted vs geographic latitude. The second EOF (red) is near zero at the equator and maximum at high latitudes (where the SZA annual variation is the greatest). The first EOF (blue) shows little variation in latitude indicating that the solar EUV effects are relatively independent of latitude. [Anderson and Hawkins, 2015] PHYS 3380 - Astronomy Why are the seasons more extreme in the Northern hemisphere? PHYS 3380 - Astronomy 1.
Load more

Recommended publications
  • Constructing a Galactic Coordinate System Based on Near-Infrared and Radio Catalogs
    A&A 536, A102 (2011) Astronomy DOI: 10.1051/0004-6361/201116947 & c ESO 2011 Astrophysics Constructing a Galactic coordinate system based on near-infrared and radio catalogs J.-C. Liu1,2,Z.Zhu1,2, and B. Hu3,4 1 Department of astronomy, Nanjing University, Nanjing 210093, PR China e-mail: [jcliu;zhuzi]@nju.edu.cn 2 key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, PR China 3 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China 4 Graduate School of Chinese Academy of Sciences, Beijing 100049, PR China e-mail: hubo@pmo.ac.cn Received 24 March 2011 / Accepted 13 October 2011 ABSTRACT Context. The definition of the Galactic coordinate system was announced by the IAU Sub-Commission 33b on behalf of the IAU in 1958. An unrigorous transformation was adopted by the Hipparcos group to transform the Galactic coordinate system from the FK4-based B1950.0 system to the FK5-based J2000.0 system or to the International Celestial Reference System (ICRS). For more than 50 years, the definition of the Galactic coordinate system has remained unchanged from this IAU1958 version. On the basis of deep and all-sky catalogs, the position of the Galactic plane can be revised and updated definitions of the Galactic coordinate systems can be proposed. Aims. We re-determine the position of the Galactic plane based on modern large catalogs, such as the Two-Micron All-Sky Survey (2MASS) and the SPECFIND v2.0. This paper also aims to propose a possible definition of the optimal Galactic coordinate system by adopting the ICRS position of the Sgr A* at the Galactic center.
    [Show full text]
  • Basic Principles of Celestial Navigation James A
    Basic principles of celestial navigation James A. Van Allena) Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 ͑Received 16 January 2004; accepted 10 June 2004͒ Celestial navigation is a technique for determining one’s geographic position by the observation of identified stars, identified planets, the Sun, and the Moon. This subject has a multitude of refinements which, although valuable to a professional navigator, tend to obscure the basic principles. I describe these principles, give an analytical solution of the classical two-star-sight problem without any dependence on prior knowledge of position, and include several examples. Some approximations and simplifications are made in the interest of clarity. © 2004 American Association of Physics Teachers. ͓DOI: 10.1119/1.1778391͔ I. INTRODUCTION longitude ⌳ is between 0° and 360°, although often it is convenient to take the longitude westward of the prime me- Celestial navigation is a technique for determining one’s ridian to be between 0° and Ϫ180°. The longitude of P also geographic position by the observation of identified stars, can be specified by the plane angle in the equatorial plane identified planets, the Sun, and the Moon. Its basic principles whose vertex is at O with one radial line through the point at are a combination of rudimentary astronomical knowledge 1–3 which the meridian through P intersects the equatorial plane and spherical trigonometry. and the other radial line through the point G at which the Anyone who has been on a ship that is remote from any prime meridian intersects the equatorial plane ͑see Fig.
    [Show full text]
  • Equatorial and Cartesian Coordinates • Consider the Unit Sphere (“Unit”: I.E
    Coordinate Transforms Equatorial and Cartesian Coordinates • Consider the unit sphere (“unit”: i.e. declination the distance from the center of the (δ) sphere to its surface is r = 1) • Then the equatorial coordinates Equator can be transformed into Cartesian coordinates: right ascension (α) – x = cos(α) cos(δ) – y = sin(α) cos(δ) z x – z = sin(δ) y • It can be much easier to use Cartesian coordinates for some manipulations of geometry in the sky Equatorial and Cartesian Coordinates • Consider the unit sphere (“unit”: i.e. the distance y x = Rcosα from the center of the y = Rsinα α R sphere to its surface is r = 1) x Right • Then the equatorial Ascension (α) coordinates can be transformed into Cartesian coordinates: declination (δ) – x = cos(α)cos(δ) z r = 1 – y = sin(α)cos(δ) δ R = rcosδ R – z = sin(δ) z = rsinδ Precession • Because the Earth is not a perfect sphere, it wobbles as it spins around its axis • This effect is known as precession • The equatorial coordinate system relies on the idea that the Earth rotates such that only Right Ascension, and not declination, is a time-dependent coordinate The effects of Precession • Currently, the star Polaris is the North Star (it lies roughly above the Earth’s North Pole at δ = 90oN) • But, over the course of about 26,000 years a variety of different points in the sky will truly be at δ = 90oN • The declination coordinate is time-dependent albeit on very long timescales • A precise astronomical coordinate system must account for this effect Equatorial coordinates and equinoxes • To account
    [Show full text]
  • Current State of Knowledge of the Magnetospheres of Uranus and Neptune
    Current State of Knowledge of the Magnetospheres of Uranus and Neptune 28 July 2014 Abigail Rymer abigail.rymer@jhuapl.edu What does a ‘normal’ magnetosphere look like? . N-S dipole field perpendicular to SW . Solar wind driven circulation system . Well defined central tail plasmasheet . Loaded flux tubes lost via substorm activity . Trapped radiation on closed (dipolar) field lines close to the planet. …but then what is normal…. Mercury Not entirely at the mercy of the solar wind after all . Jupiter . More like its own little solar system . Sub-storm activity maybe totally internally driven …but then what is normal…. Saturn Krimigis et al., 2007 What is an ice giant (as distinct from a gas giant) planet? Consequenses for the magnetic field Soderlund et al., 2012 Consequenses for the magnetic field Herbert et al., 2009 Are Neptune and Uranus the same? URANUS NEPTUNE Equatorial radius 25 559 km 24 622 km Mass 14.5 ME 17.14 ME Sidereal spin period 17h12m36s (retrograde) 16h6m36s Obliquity (axial tilt to ecliptic) -97.77º 28.32 Semi-major axis 19.2 AU 30.1 AU Orbital period 84.3 Earth years 164.8 Earth years Dipole moment 50 ME 25 ME Magnetic field Highly complex with a surface Highly complex with a surface field up to 110 000 nT field up to 60 000 nT Dipole tilt -59º -47 Natural satellites 27 (9 irregular) 14 (inc Triton at 14.4 RN) Spacecraft at Uranus and Neptune – Voyager 2 Voyager 2 observations - Uranus Stone et al., 1986 Voyager 2 observations - Uranus Voyager 2 made excellent plasma measurements with PLS, a Faraday cup type instrument.
    [Show full text]
  • Solar Illumination Conditions at 4 Vesta: Predictions Using the Digital Elevation Model Derived from Hst Images
    42nd Lunar and Planetary Science Conference (2011) 2506.pdf SOLAR ILLUMINATION CONDITIONS AT 4 VESTA: PREDICTIONS USING THE DIGITAL ELEVATION MODEL DERIVED FROM HST IMAGES. T. J. Stubbs 1,2,3 and Y. Wang 1,2,3 , 1Goddard Earth Science and Technology Center, University of Maryland, Baltimore County, Baltimore, MD, USA, 2NASA Goddard Space Flight Center, Greenbelt, MD, USA, 3NASA Lunar Science Institute, Ames Research Center, Moffett Field, CA, USA. Corresponding email address: Timothy.J.Stubbs[at]NASA.gov . Introduction: As with other airless bodies in the plane), the longitude of the ascending node is 103.91° Solar System, the surface of 4 Vesta is directly exposed and the argument of perihelion is 149.83°. Based on to the full solar spectrum. The degree of solar illumina- current estimates, Vesta’s orbital plane is believed to tion plays a major role in processes at the surface, in- have a precession period of 81,730 years [6]. cluding heating (surface temperature), space weather- For the shape of Vesta we use the 5 × 5° DEM ing, surface charging, surface chemistry, and exo- based on HST images [5], which is publicly available spheric production via photon-stimulated desorption. from the Planetary Data System (PDS). To our knowl- The characterization of these processes is important for edge, this is the best DEM of Vesta currently available. interepreting various surface properties. It is likely that The orbital information for Vesta is obtained from the solar illumination also controls the transport and depo- Dawn SPICE kernel, which currently limits us to the sition of volatiles at Vesta, as has been proposed at the current epoch (1900 to present).
    [Show full text]
  • The Sky Tonight
    MARCH POUTŪ-TE-RANGI HIGHLIGHTS Conjunction of Saturn and the Moon A conjunction is when two astronomical objects appear close in the sky as seen THE- SKY TONIGHT- - from Earth. The planets, along with the TE AHUA O TE RAKI I TENEI PO Sun and the Moon, appear to travel across Brightest Stars our sky roughly following a path called the At this time of the year, we can see the ecliptic. Each body travels at its own speed, three brightest stars in the night sky. sometimes entering ‘retrograde’ where they The brightness of a star, as seen from seem to move backwards for a period of time Earth, is measured as its apparent (though the backwards motion is only from magnitude. Pictured on the cover is our vantage point, and in fact the planets Sirius, the brightest star in our night sky, are still orbiting the Sun normally). which is 8.6 light-years away. Sometimes these celestial bodies will cross With an apparent magnitude of −1.46, paths along the ecliptic line and occupy the this star can be found in the constellation same space in our sky, though they are still Canis Major, high in the northern sky. millions of kilometres away from each other. Sirius is actually a binary star system, consisting of Sirius A which is twice the On March 19, the Moon and Saturn will be size of the Sun, and a faint white dwarf in conjunction. While the unaided eye will companion named Sirius B. only see Saturn as a bright star-like object (Saturn is the eighth brightest object in our Sirius is almost twice as bright as the night sky), a telescope can offer a spectacular second brightest star in the night sky, view of the ringed planet close to our Moon.
    [Show full text]
  • Our Solar System
    This graphic of the solar system was made using real images of the planets and comet Hale-Bopp. It is not to scale! To show a scale model of the solar system with the Sun being 1cm would require about 64 meters of paper! Image credit: Maggie Mosetti, NASA This book was produced to commemorate the Year of the Solar System (2011-2013, a martian year), initiated by NASA. See http://solarsystem.nasa.gov/yss. Many images and captions have been adapted from NASA’s “From Earth to the Solar System” (FETTSS) image collection. See http://fettss.arc.nasa.gov/. Additional imagery and captions compiled by Deborah Scherrer, Stanford University, California, USA. Special thanks to the people of Suntrek (www.suntrek.org,) who helped with the final editing and allowed me to use Alphonse Sterling’s awesome photograph of a solar eclipse! Cover Images: Solar System: NASA/JPL; YSS logo: NASA; Sun: Venus Transit from NASA SDO/AIA © 2013-2020 Stanford University; permission given to use for educational and non-commericial purposes. Table of Contents Why Is the Sun Green and Mars Blue? ............................................................................... 4 Our Sun – Source of Life ..................................................................................................... 5 Solar Activity ................................................................................................................... 6 Space Weather ................................................................................................................. 9 Mercury
    [Show full text]
  • 3.- the Geographic Position of a Celestial Body
    Chapter 3 Copyright © 1997-2004 Henning Umland All Rights Reserved Geographic Position and Time Geographic terms In celestial navigation, the earth is regarded as a sphere. Although this is an approximation, the geometry of the sphere is applied successfully, and the errors caused by the flattening of the earth are usually negligible (chapter 9). A circle on the surface of the earth whose plane passes through the center of the earth is called a great circle . Thus, a great circle has the greatest possible diameter of all circles on the surface of the earth. Any circle on the surface of the earth whose plane does not pass through the earth's center is called a small circle . The equator is the only great circle whose plane is perpendicular to the polar axis , the axis of rotation. Further, the equator is the only parallel of latitude being a great circle. Any other parallel of latitude is a small circle whose plane is parallel to the plane of the equator. A meridian is a great circle going through the geographic poles , the points where the polar axis intersects the earth's surface. The upper branch of a meridian is the half from pole to pole passing through a given point, e. g., the observer's position. The lower branch is the opposite half. The Greenwich meridian , the meridian passing through the center of the transit instrument at the Royal Greenwich Observatory , was adopted as the prime meridian at the International Meridian Conference in 1884. Its upper branch is the reference for measuring longitudes (0°...+180° east and 0°...–180° west), its lower branch (180°) is the basis for the International Dateline (Fig.
    [Show full text]
  • 2. Descriptive Astronomy (“Astronomy Without a Telescope”)
    2. Descriptive Astronomy (“Astronomy Without a Telescope”) http://apod.nasa.gov/apod/astropix.html • How do we locate stars in the heavens? • What stars are visible from a given location? • Where is the sun in the sky at any given time? • Where are you on the Earth? An “asterism” is two stars that appear To be close in the sky but actually aren’t In 1930 the International Astronomical Union (IAU) ruled the heavens off into 88 legal, precise constellations. (52 N, 36 S) Every star, galaxy, etc., is a member of one of these constellations. Many stars are named according to their constellation and relative brightness (Bayer 1603). Sirius α − Centauri, α-Canis declination less http://calgary.rasc.ca/constellation.htm - list than -53o not Majoris, α-Orionis visible from SC http://www.google.com/sky/ Betelgeuse https://en.wikipedia.org/wiki/List_of_Messier_objects (1758 – 1782) Biggest constellation – Hydra – the female water snake 1303 square degrees, but Ursa Major and Virgo almost as big. Hydrus – the male water snake is much smaller – 2243 square degrees Smallest is Crux – the Southern Cross – 68 square degrees Brief History Some of the current constellations can be traced back to the inhabitants of the Euphrates valley, from whom they were handed down through the Greeks and Arabs. Few pictorial records of the ancient constellation figures have survived, but in the Almagest AD 150, Ptolemy catalogued the positions of 1,022 of the brightest stars both in terms of celestial latitude and longitude, and of their places in 48 constellations. The Ptolemaic constellations left a blank area centered not on the present south pole but on a point which, because of precession, would have been the south pole c.
    [Show full text]
  • Celestial Sphere, Solar Motion, Coordinates
    Celestial Sphere, Solar Motion, Coordinates Lecture Outline -- 1 Reading: Astronomy Notes sections 3.1 through 3.5 Vocabulary terms used: celestial poles⎯points on celestial sphere directly above geographic poles. celestial equator⎯circle around the sky directly above the Earth’s equator. zenith⎯point on the celestial sphere that is always straight overhead. meridian⎯circle around the sky that goes through celestial poles and the zenith point. Separates the daytime motions of the Sun into “a.m.” and “p.m.”. solar day⎯time between successive meridian crossings of the Sun. Our clocks are based on this. ecliptic⎯the apparent yearly path of the Sun through the stars on the celestial sphere. It is the projection of the Earth’s orbit around the Sun onto the celestial sphere. vernal equinox⎯specific moment in the year (on March 21) when the Sun is directly on the celestial equator, moving north of the celestial equator. autumnal equinox⎯specific moment in the year (on September 22) when the Sun is directly on the celestial equator, moving south of the celestial equator. season⎯approximately three-month period bounded by an equinox and a solstice. solstice⎯specific moment in the year when the Sun is farthest away from the celestial equator. The summer solstice is when the Sun gets closest to zenith at noon (on June 21 for U.S.). The winter solstice is when the Sun gets closest to the horizon at noon (on December 21 for U.S.). latitude⎯used to specify position on the Earth, it is the number of degrees north or south of the Earth’s equator.
    [Show full text]
  • 1 the Equatorial Coordinate System
    General Astronomy (29:61) Fall 2013 Lecture 3 Notes , August 30, 2013 1 The Equatorial Coordinate System We can define a coordinate system fixed with respect to the stars. Just like we can specify the latitude and longitude of a place on Earth, we can specify the coordinates of a star relative to a coordinate system fixed with respect to the stars. Look at Figure 1.5 of the textbook for a definition of this coordinate system. The Equatorial Coordinate System is similar in concept to longitude and latitude. • Right Ascension ! longitude. The symbol for Right Ascension is α. The units of Right Ascension are hours, minutes, and seconds, just like time • Declination ! latitude. The symbol for Declination is δ. Declination = 0◦ cor- responds to the Celestial Equator, δ = 90◦ corresponds to the North Celestial Pole. Let's look at the Equatorial Coordinates of some objects you should have seen last night. • Arcturus: RA= 14h16m, Dec= +19◦110 (see Appendix A) • Vega: RA= 18h37m, Dec= +38◦470 (see Appendix A) • Venus: RA= 13h02m, Dec= −6◦370 • Saturn: RA= 14h21m, Dec= −11◦410 −! Hand out SC1 charts. Find these objects on them. Now find the constellation of Orion, and read off the Right Ascension and Decli- nation of the middle star in the belt. Next week in lab, you will have the chance to use the computer program Stellar- ium to display the sky and find coordinates of objects (stars, planets). 1.1 Further Remarks on the Equatorial Coordinate System The Equatorial Coordinate System is fundamentally established by the rotation axis of the Earth.
    [Show full text]
  • Effects of the Moon on the Earth in the Past, Present, and Future
    Effects of the Moon on the Earth in the Past, Present, and Future Rina Rast*, Sarah Finney, Lucas Cheng, Joland Schmidt, Kessa Gerein, & Alexandra Miller† Abstract The Moon has fascinated human civilization for millennia. Exploration of the lunar surface played a pioneering role in space exploration, epitomizing the heights to which modern science could bring mankind. In the decades since then, human interest in the Moon has dwindled. Despite this fact, the Moon continues to affect the Earth in ways that seldom receive adequate recognition. This paper examines the ways in which our natural satellite is responsible for the tides, and also produces a stabilizing effect on Earth’s rotational axis. In addition, phenomena such as lunar phases, eclipses and lunar libration will be explained. While investigating the Moon’s effects on the Earth in the past and present, it is hoped that human interest in it will be revitalized as it continues to shape life on our blue planet. Keywords: Moon, Earth, tides, Earth’s axis, lunar phases, eclipses, seasons, lunar libration Introduction lunar phases, eclipses and libration. In recognizing and propagating these effects, the goal of this study is to rekindle the fascination humans once held for the Moon Decades have come and gone since humans’ fascination and space exploration in general. with the Moon galvanized exploration of the galaxy and observation of distant stars. During the Space Race of the 1950s and 1960s, nations strived and succeeded in reaching Four Prominent Lunar Effects on Earth Earth’s natural satellite to propel mankind to new heights. Although this interest has dwindled and humans have Effect on Oceans and Tides largely distanced themselves from the Moon’s relevance, its effects on Earth remain as far-reaching as ever.
    [Show full text]