Phase angle in astronomical observations is the angle between the light incident onto an observed object and the light reflected from the object. In the context of astronomical observations, this is usually the angle Sun-object-observer. For terrestrial observations, "Sun–object–Earth" is often nearly the same thing as "Sun–object–observer", since the difference depends on the parallax, which in the case of observations of the Moon can be as much as 1°, or two full Moon diameters. With the development of space travel, as well as in hypothetical observations from other points in space, the notion of phase angle became independent of Sun and Earth. The etymology of the term is related to the notion of planetary phases, since the brightness of an object and its appearance as a "phase" is the function of the phase angle. The phase angle varies from 0° to 180°. The value of 0° corresponds to the position where the illuminator, the observer, and the object are collinear, with the illuminator and the observer on the same side of the object. The value of 180° is the position where the object is between the illuminator and the observer, known as inferior conjunction. Values less than 90° represent backscattering; values greater than 90° represent forward scattering. For some objects, such as the Moon (see lunar phases), Venus and Mercury the phase angle (as seen from the Earth) covers the full 0–180° range. The superior planets cover shorter ranges. For example, for Mars the maximum phase angle is about 45°. The brightness of an object is a function of the phase angle, which is generally smooth, except for the so-called opposition spike near 0°, which does not affect gas giants or bodies with pronounced atmospheres, and when the object becomes fainter as the angle approaches 180°. This relationship is referred to as the phase curve. (Wikipedia).
Astronomy - Ch. 5: Light & E&M Radiation (29 of 30) Doppler Shift and Rotation of Celestial Objects
Visit http://ilectureonline.com for more math and science lectures! In this video I will explain how to use the Doppler shift to understand the rotation of celestial objects.
From playlist ASTRONOMY 5 LIGHT AND RADIATION
Gradient (2 of 3: Angle of inclination)
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From playlist Further Linear Relationships
Astronomy - Ch. 2: Understanding the Night Sky (8 of 23) Understanding Celestial Coordinates
Visit http://ilectureonline.com for more math and science lectures! In this video I will explain the coordinates of the celestial sphere.
From playlist ASTRONOMY 2 THE NIGHT SKY
Astronomy - Ch. 17: The Nature of Stars (7 of 37) Using Angle of Parallax to Find Distances
Visit http://ilectureonline.com for more math and science lectures! In this video I will explain how the angle of parallax is used to find the distances of stars. Next video can be seen at: http://youtu.be/4XZ8GxsqdlA
From playlist ASTRONOMY 17 STARS AND THE H-R DIAGRAM
Teach Astronomy - Orbit Inclination
http://www.teachastronomy.com/ For most planets in the solar system the orbital inclination is very small. That is, the axis defined by the north and south poles of the planet is almost exactly perpendicular to the plane of the planet's orbit of the Sun. The only two exceptions to this a
From playlist 10. The Solar System
Star Paths: The Magic Of Observational Astronomy (Part 1)
Credit to: Veena Srinivasan (Animation and Graphics) See Part 2: https://www.youtube.com/watch?v=BuQMhBjN5AI Correction: At 12:13 I meant to say simply "zenith angle" and "azimuth angle" rather than "solar zenith angle" and "solar azimuth angle" ; the latter terms would refer solely to the
From playlist Summer of Math Exposition Youtube Videos
Teach Astronomy - Celestial Sphere
http://www.teachastronomy.com/ The celestial sphere is an imaginary sphere surrounding the Earth onto which are projected the objects of the night sky. There are several fixed points on the celestial sphere that are important. The Zenith is the point directly over your head. The Nadir i
From playlist 02. Ancient Astronomy and Celestial Phenomena
http://www.teachastronomy.com/ Parallax is the shift of angle when something is observed from two different perspectives. If you hold your finger out in front of your face and observe it with one eye and then the other you will notice the shift, or the parallax shift, relative to a distan
From playlist 03. Concepts and History of Astronomy and Physics
Cosmology with Gravitational Waves (Lecture 1) by Archisman Ghosh
Program Cosmology - The Next Decade ORGANIZERS : Rishi Khatri, Subha Majumdar and Aseem Paranjape DATE : 03 January 2019 to 25 January 2019 VENUE : Ramanujan Lecture Hall, ICTS Bangalore The great observational progress in cosmology has revealed some very intriguing puzzles, the most i
From playlist Cosmology - The Next Decade
Moon Phases: Crash Course Astronomy #4
In this episode of Crash Course Astronomy, Phil takes you through the cause and name of the Moon's phases. Check out the Crash Course Astronomy solar system poster here: http://store.dftba.com/products/crashcourse-astronomy-poster -- Chapters: Why does the Moon Have Phases? 00:00 New Moo
From playlist Astronomy
Teach Astronomy - Measuring Angles
http://www.teachastronomy.com/ Angular measurement is an important part of astronomy. When you want to quote the position of an object on the sky you give it in terms of two different angles. The basic unit of angular measurement is a degree. There are 90 degrees in a right angle and 36
From playlist 01. Fundamentals of Science and Astronomy
Moon and Eclipses | History and Philosophy of Astronomy 1.06
Learn about the history and philosophy of astronomy from Professor Impey, a University Distinguished Professor of Astronomy at the University of Arizona, with our Knowing the Universe: History and Philosophy of Astronomy course here on YouTube. This video is part of module 1, Ancient Skies
From playlist History and Philosophy Course Module 1: Ancient Skies
Galileo | Introductory Astronomy Course 1.16
Welcome to Astronomy: Exploring Time and Space, a course from Professor Impey, a University Distinguished Professor of Astronomy at the University of Arizona. Learn about the foundations of astronomy in this free online course here on YouTube. This video is part of module 1, Science and Hi
From playlist Introductory Astronomy Module 1: Science and History
Overview: Multi-messenger astronomy of compact binary mergers by Kenta Hotokezaka
Discussion Meeting The Future of Gravitational-Wave Astronomy ORGANIZERS: Parameswaran Ajith, K. G. Arun, B. S. Sathyaprakash, Tarun Souradeep and G. Srinivasan DATE: 19 August 2019 to 22 August 2019 VENUE: Ramanujan Lecture Hall, ICTS Bangalore This discussion meeting, organized in c
From playlist The Future of Gravitational-wave Astronomy 2019
Early Telescope | History and Philosophy of Astronomy 4.02
Learn about the history and philosophy of astronomy from Professor Impey, a University Distinguished Professor of Astronomy at the University of Arizona, with our Knowing the Universe: History and Philosophy of Astronomy course here on YouTube. This video is part of module 4, Telescope. C
From playlist History and Philosophy Course Module 4: Telescope
Skynet University: http://skynet.unc.edu/introastro Use Our Telescopes From Anywhere! Astronomy 101: The Solar System Lesson 2: Copernican Revolution Topic: Stonehenge Next: Geocentric Models (http://youtu.be/oJ51wyoth4Q) Previous: Lesson 1 (http://www.youtube.com/playlist?list=PL9
From playlist UNC: Astronomy 101 by Skynet University | CosmoLearning.org Astronomy
Interferometers | Introductory Astronomy Course 3.05
Welcome to Astronomy: Exploring Time and Space, a course from Professor Impey, a University Distinguished Professor of Astronomy at the University of Arizona. Learn about the foundations of astronomy in this free online course here on YouTube. This video is part of module 3, Telescopes. W
From playlist Introductory Astronomy Module 3: Telescopes
Advanced LIGO in the dawn of gravitational-wave astronomy by Stan Whitcomb
The Future of Gravitational-Wave Astronomy URL: http://www.icts.res.in/discussion_meeting/fgwa2016/ DATES: Monday 04 Apr, 2016 - Friday 08 Apr, 2016 VENUE : Ramanujan Lecture Hall, ICTS Bangalore DESCRIPTION: On 2016 February 11, two major international collaborations jointly announce
From playlist The Future of Gravitational-Wave Astronomy
Gravity: Newtonian, post-Newtonian, Relativistic (Lecture 9) by Clifford M Will
DATES Monday 25 Jul, 2016 - Friday 05 Aug, 2016 VENUE Madhava Lecture Hall, ICTS Bangalore APPLY Over the last three years ICTS has been organizing successful summer/winter schools on various topics of gravitational-wave (GW) physics and astronomy. Each school from this series aimed at foc
From playlist Summer School on Gravitational-Wave Astronomy
Astronomy - Ch. 5: Light & E&M Radiation (26 of 30) Doppler Shift and Celestial Radial Movement
Visit http://ilectureonline.com for more math and science lectures! In this video I will explain how to use the Doppler shift when a sun is moving at an angle away or towards Earth.
From playlist ASTRONOMY 5 LIGHT AND RADIATION