Karen Meech Institute for Astronomy TOPS 2003

Slides:

Advertisements

Similar presentations

Coordinate System & Time/Calendar

Advertisements

Comet Machholz passes the Pleiades. Comet Machholz C/2004 Q2 Discovered byDonald Machholz, Jr. on August 27, 2004 Period of about 120,000 years Just up.

Chapter S1 Celestial Timekeeping and Navigation

PHYS 1025 – Introductory Astronomy Lecture 2, Either Semester

Apparent/Actual Motions Summary

Celestial Sphere Stars seem to be on the inner surface of a sphere surrounding the Earth.

The Earth Rotates.

Review Questions How do you write Scientific Notation? How do you write Scientific Notation? What is the difference between Angular Measurements and Linear.

An Earth Day Sidereal Day: 23 hr 56 min 4 sec Motion relative to background stars Mean Solar Day: 24 hours The average time between meridian crossings.

Astronomy 104 Lunar Phases AndEclipses January 24, 2007.

PHY134 Introductory Astronomy

Today’s Lecture How to find astronomical objects

The Celestial Sphere The 88 official constellations cover the celestial sphere. If you do not have a model of the celestial sphere to bring to class, you.

Grab your text book Chapter 1 Astronomy Today 7th Edition

Patterns in the Sky (cont)

ASTR211 EXPLORING THE SKY Coordinates and time Prof. John Hearnshaw.

Section 3 Constellations  Sections of sky with recognizable star patterns  Used by ancient people for navigation  Also used to keep track of time.

2. The Celestial Sphere Goals Goals: 1. Gain familiarity with the basic coordinate systems used in astronomy. 2. Tackle simple problems in practical.

Celestial Sphere. Local View On earth objects are usually viewed in flat Euclidean geometry. From the earth the stars appear to be fixed on a sphere that.

Daily Motion of the Sun Daily motion (diurnal motion) along a circle with center on the Earth’s axis Clockwise in the north temperate zone Counterclockwise.

The Contents of the Milky Way Our Galaxy has a disk about 50 kpc (160,000 ly) in diameter and about 600 pc (2000 ly) thick, with a high concentration of.

Introduction to Astronomy.  Observations lead to theories and laws  Laws are concise statements that summaries a large number of observations.  Theories.

The Celestial Sphere Stars at different distances all appear to lie on the celestial sphere. The 88 official constellations cover the celestial sphere.

Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. Dark sand.

The Seasons There would be no seasons if the Earth were not tilted on it’s axis!  Nick Devereux 2006.

Observational Astrophysics in the visible light Shai Kaspi Technion - March 2015.

Terrestrial Coordinates (useful for specifying locations on the surface of the Earth) Longitude - Longitude -- East/West Coordinate -- 0  at the Prime.

Knowing The Heavens Hawaii: latitude 20 deg Washington D.C.: latitude 38 deg.

 There are 2 types: i. Az/Alt. -The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental.

Last time: 2.1. Patterns in The Sky: Stars and constellations, TODAY: celestial coordinates 2.2 Seasons,…Precession 2.2 (cont.) The Moon and Eclipses.

Where is it? On the Celestial Sphere. Longitude and Latitude On Earth: Longitude is how far you are, in degrees, East or West of the “Prime Meridian”

Coordinate Systems.

Celestial Sphere. Earthly Sphere Latitude measures the number of degrees north or south of the equator. –DeKalb at 41° 55’ N Longitude measures degrees.

A scientific model.  Why do we use the model of the celestial sphere when studying the night sky, even though it does not accurately represent three-dimensional.

Announcements Clear sky patrol has not yet started We will start using PRS units this week, make sure that you have one.

Introduction to Positional Astronomy The Night Sky  Nick Devereux 2006.

1 Lines in the Sky In order to use the sky to measure time you need to measure the location of objects in the sky. We will look at two methods of measuring.

EARTH IN SPACE. A reminder about earth  The earth is almost a sphere  We locate points on the sphere with 3 coordinates – Longitude (180º W º.

Celestial Navigation Celestial Motion 1. General Organization Original “celestial sphere” model devised by the Greeks is still used –Greeks saw the Earth.

1.Stars move from east to west over the course of the night 2.Change slightly from one night to the next 3.However, their relative positions remain.

Sky Motions  Diurnal Motion Annual Motion. DIURNAL MOTION o Daily East / West motion of the sky Due to the Earth’s rotation (15°/hour) [360°/24 hours.

Celestial Motions And Celestial Sphere.

Universe Tenth Edition Chapter 2 Knowing the Heavens Roger Freedman Robert Geller William Kaufmann III.

Constellations come, and climb the heavens, and go, And thou dost see them rise, Star of the Pole! and thou dost see them set, Alone,

AstroLab-2 Locating Stars in the Sky Merav Opher-Fall 2004.

Local and Sky Coordinates

ASTRONOMICAL OBSERVATIONS Astronomical Observations.

MOTIONS OF SKY. Goals To identify the different parts of the celestial sphere model To understand how to express the location of objects in the sky To.

Our Location on the Earth North South EastWest North South East you are here West.

Chapter 4: Rising & Setting Stars © BRIEF

Observational Astronomy Mapping the Heavens Coordinate Systems We have two different ways to locate objects in the sky: Celestial equatorial system -Right.

Lecture 3 -- Astronomical Coordinate Systems Constellation of the Day…Aquila constellations.

Phases of the Moon Lab The Celestial Sphere Model One way the celestial sphere model is used explains positions in the sky as seen from YOUR position.

The Celestial Sphere (The sphere should really be rotating, not Earth)

Research Experiences for Undergraduates (REU)

Constellations Astronomy: A pattern of stars Astrology

The Night Sky…last time, The Horizon System

Positional Astronomy Chapter 3 Fundamentals of Radio Interferometry

Constellation – Sky Familiarization

Finding Your Way Around the Night Sky

Stargazing Terminology

Local and Sky Coordinates

Horizon Coordinates A: Azimuth. The angle measured beginning at cardinal pt. north eastward along the horizon to the base of the vertical circle of the.

Finding Your Way In the Sky

The Sky (Celestial Sphere)

On the Celestial Sphere

ASTRO UNIT 1 REVIEW.

On the Celestial Sphere

Celestial Sphere Practice Quiz

Fundamentals of Geodesy

Presentation transcript:

Karen Meech Institute for Astronomy TOPS 2003 The Celestial Sphere Karen Meech Institute for Astronomy TOPS 2003

Latitude and Longitude Latitude (f) meas from equator Longitude (l) point of reference – Greenwich UK Units of measure: Deg, arcmin, arcsec O ‘ “

The Horizon System Altitude (h) – angle measured from the horizon to Zenith (Z) Azimuth – the angle measured from NE along horizon Problem as a celestial system?

Celestial Sphere Imaginary sphere where stars reside Extension of Earth’s equator, poles Celestial Equator Celestial poles Zenith & Nadir

Great Circles Circles covering the largest diameter on sphere NCP altitude = f Celestial Meridian – CM great circle through Z and NCP Hour Angle – angular distance / time from CM HA = 0 on CM “-” indicates rising “+” indicates setting

Declination & Right Ascension Declination = Latitude Celestial Equator d = 0 Latitude, NCP elevation Units: deg, arcmin, ‘’ The Celestial Meridian Great circle going through zenith & NCP Right Ascension = Longitude Units: hh:mm:ss 360o = 24 hr (1 hr = 15o) Where to start RA?

Circles of Declination

The Ecliptic & Seasons Obliquity – tilt of Earth’s orbital axis (23.5o) Ecliptic – path of the Earth around the sun Apparent path of the sun & planets in the sky Traces a great circle on the celestial sphere Intersects at 2 points: ^ and d (vernal & autumnal equinox) ^ is visible at midnight on CM in September

The Ecliptic

Right Ascension Starting Point Longitude system: Prime Meridian Two intersections between CE & ecliptic Vernal Equinox Autumnal Equinox Units of measure: Hours, min, sec Measure Eastward from ^ (RA = 0) RA increases to E

Time Scales UT/Local – measured from noon to noon (movement of sun) Earth’s orbital motion  must rotate >360o q = 360/365.25 = 0.986o 24 : (360+ q) = sidereal : 360 Sidereal day = 23h 56m 04s Start defined when ^ is on the celestial meridian

Relation between ST and RA HA = ST – RA ST at night = RA of object on CM ^ is on the CM at midnight at d Observing tip RA = 0 on CM in Sep Advances 2 hr / mo

Airmass – Coordinate Relations Best observe @ HA = 0 Airmass – amt of atm Extinction = absorption & scattering c = sec(ZD) Spherical Trig – law of cosines cos(s1) = cos(s2)cos(s3) + sin(s2)sin(s3)cos(A1)

Effect of Airmass c = sec(z) = sin(d) sin (f) + cos(d) cos(f) cos(HA) Higher airmass = more extinction Higher airmass = more refraction Higher airmass = poorer seeing

Summary Coordinates: a, d CM – passes thru Z and NCP a increases to E Altitude of NCP = f HA = ST – a ^ is on CM at d Best obs at small HA (small c)

The Astrolabe 2-D model of csphere Greek origins: astron + lambanien Ancient laptop! Oldest about 900 BC (Hipparchus) Middle Ages Arabian astronomers

Astrolabe Functions View of night sky Position of stars Rise/set of sun, stars Altitude of object Measure time of year Measure time of night

Transparent Overlay

RA / Dec Grid

Elevation Guide

Astrolabe Exercises The Sky Tonight When an object rises or sets Sunset for 6/20/02 RA = 05:58:31 Dec = +23:26:18 04:56 UT Determine the time of year The Astrolabe timepiece