| Galaxies | |
| M101 Pinwheel Galaxy Supernova - Dwarf II Telescope | (13 minutes) This video discusses the recent (May 2023) supernova in the Pinwheel Galaxy (M101) and how I took pictures of the galaxy and supernova with the Dwarf II automated telescope from late May up to early in July. Information is given on the Pinwheel Galaxy, the Dwarf II telescope, and how I processed the images. Note that I was not consistent in how I cropped the photos. There is an arrow pointing to the supernova in each picture but you will see the supernova at different positions relative the the galaxy. This is an artifact of how I cropped the image and is NOT due to the rotation of the galaxy. See astronomy.gpclements.com and physics.gpclements.com for a list of my other YouTube videos. |
| Andromeda Galaxy: Location on Sky, Some Facts, Images | (11 minutes) This video describes the location of the Andromeda galaxy on the sky, gives a few facts about the galaxy, and shows images of the galaxy in visible, ultraviolet, and infrared light. Doppler shift evidence for the supermassive black hole at the center of the galaxy is briefly discussed. |
| Local Group of Galaxies, A Quick Tour | (20 minutes) This video shows sketches, maps, and photos of the Local Group of Galaxies. The Andromeda, Milky Way, and Triangulum galaxies are highlighted. The companion galaxies for Andromeda are discussed. The companion galaxies of the Milky Way, the Large Magellanic and Small Magellanic Clouds, are discussed. Approximate masses (from Google searches) are given. A few details of the Milky Way and Andromeda galaxies are discussed. |
Island Universe Debate, Cepheid Variable Stars |
(15 minutes) This video discusses the debate in the early 1900s as to the location of some nebulae in relation to the Milky Way Galaxy. Shapley and Curtis debated the size of the universe and nature of the nebulae in 1920. In the 1700s Kant used the term "Island Universe" to describe some of the nebulae as he believed they were there own large collection of stars, what we now call galaxies. The video summarizes some of the reasoning for both sides of the debate. The video describes the light variability of Cepheid stars and the period luminosity relationship. The video also has a sequence of sketches and photographs of the Whirlpool Galaxy as astronomy technology improved from 1845 to 2005. |
| Zone of Avoidance, Distribution of Galaxies | (10 minutes) This video gives a brief description, history, and explanation for the "Zone of Avoidance." The distribution of galaxies over the sky is shown for visible and infrared wavelengths. |
| Types of Galaxies: Spiral, Elliptical, Irregular Hubble Images | ( 15 minutes) This video uses graphics and Hubble images to briefly describe spiral, barred spiral, elliptical, and irregular galaxies. The characteristics of spiral, elliptical, and irregular galaxies are listed. I plan to post other videos that focus on each type and comment on theories of galaxy formation. |
| Large Elliptical Galaxies, Hubble Photos, Characteristics, Formation Theories | (11 minutes) This video gives a brief overview of Elliptical Galaxies. Hubble photos of elliptical galaxies are presented. Their main features are noted and a general description is given on how they might have formed. |
| Supermassive Black Holes in Galaxies, Detection, Correlation to Galaxy Mass | (12 minutes) This video describes how it was determined that a supermassive black hole exists at the center of the Milky Way Galaxy. The video also describes how supermassive black holes are detected in more distant galaxies,. A brief explanation is given on the connection between the mass of the supermassive black hole and the mass of the host elliptical galaxy or the mass of the bulge of the host spiral galaxy. URLs are given for further reading and viewing of videos. |
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| Nebulae | |
| M1 Crab Nebula | (7 minutes) This video gives some historical and scientific background for the Crab Nebula. This supernova remnant is located on the sky in the constellation of Taurus. It is also known as M1 since it is the first object listed in Messier's list of objects that are not comets. I give a description of the Messier Catalog in this YouTube video: https://youtu.be/b3A4Bdb-5-Q |
| Eagle Nebula, Pillars of Creation, Images, Brief Explanations | (10 minutes) This video shows the location of the Eagle Nebula on the sky, shows images made with ground based telescopes (1973 and later), and shows images made with the Hubble Telescope (1995 and 2015). A brief discussion of what created the "Pillars of Creation," which are inside the Eagle Nebula, is given. Visible light and InfraRed light photographs are shown. |
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| Misc | |
| Globular Clusters, Characteristics, How They Are Used By Astronomers | (21 minutes) This video gives basic characteristics of Globular Clusters (GCs). GCs are compared to Open Clusters. Images of GCs are shown. The role GCs played in locating the position of the Sun in the Milky Way galaxy is briefly described. The usefulness of GC's for understanding the life stages of a star is described using a HR Diagram. The "turn off" point is described. Blue Stragglers, Mass Sorting, and GCs around other galaxies are briefly discussed. References are given for further reading and study. |
| V838 Monocerotis Light Echo Hubble Images | (9 minutes)This video gives some facts about the "light echo" observed around the star V838 Monocerotis. Six Hubble Telescope images are displayed. The location of the star in the Milky Way Galaxy is shown. Introductory Astronomy, Please subscribe to my YouTube channel. |
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| Messier Objects | |
| Messier Catalog,, History and Survey of Objects | (13 minutes) This video briefly discusses the history behind the Messier Catalog and gives a survey of the objects in the catalog. This list of objects was created by the French astronomer Messier in the 1700's as an aid to help in the search for comets by avoiding false sightings of objects that somewhat resemble distant comets. |
| M1 Crab Nebula | (7 minutes) This video gives some historical and scientific background for the Crab Nebula. This supernova remnant is located on the sky in the constellation of Taurus. It is also known as M1 since it is the first object listed in Messier's list of objects that are not comets. I give a description of the Messier Catalog in this YouTube video: https://youtu.be/b3A4Bdb-5-Q |
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| Solar System | |
| Hubble Images of Mars From 1990 to 2016, Photos at Opposition | (10 minutes)This video shows images of Mars taken by the Hubble Telescope near the time of opposition of Mars. The photos start in 1990 and end at 2016. The meaning of the term opposition is explained. The reason the angular size of Mars changes from one opposition to the next is explained. The time period between successive oppositions is given |
| Pluto After New Horizons Flyby | Lecture (15 minutes) This video briefly mentions the discovery of Pluto, the orbit of Pluto, the discovery of Charon, the change of Pluto to Dwarf Planet status. The video shows a few images from the New Horizons flyby in 2015 and discusses some of the scientific results. Pluto and Charon are compared to our Moon. This material applies to Chapter 10 of astronomynotes.com. PHY121 SCIE1300 Introductory Astronomy 101 |
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| General Interest | ||
| Seasons Are Due To Angle of Sun Not Distance | (11 minutes) This video shows calculations that explain why the angle of the Sun causes the seasons for the Northern Hemisphere. The video also shows calculations that explain why the distance to the Sun does not cause the seasons. I briefly discuss the concept of the length of time the Sun is above the horizon in each season but no calculations are done for this concept. | |
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| Unit 4 | |
| Jupiter Saturn Conjunction December 2020 Video 1 | (11 minutes) This videos describes conjunctions, shows orbits of planets, shows photos of the sky with Jupiter and Saturn, and shows the angular separation of Jupiter and Saturn on December 21, 2020. |
| Jupiter Saturn 2020 Conjunction My Photos-Angle Measurements | (9 minutes) This video shows my photos of the sky with Jupiter and Saturn. I have cropped and enhanced the photos so I could measure the distance between reference stars, and Jupiter and Saturn. I describe how I calculated the angular distance between Jupiter and Saturn from the photos. |
| Jupiter Saturn Conjunction-Why 20 Years Between Successive Conjunctions | (21 minutes) This video briefly describes the 2020 conjunction of Jupiter and Saturn. Orbit diagrams are used to explain why the length of time between conjunctions is about 20 years. The time between alignments of Jupiter and Saturn, as viewed by an observer on the Sun, is calculated assuming circular orbits. The effect of the location of the Earth in its orbit on the time between conjunctions is briefly discussed. |
| Jupiter Saturn Conjunction 2020 My Photos and Measurements Nov to Dec | (5 minutes) This video shows my photos of Saturn and Jupiter from Nov 19 to Dec 21, 2020. I Used a DSLR on a tripod to take the photos. I discuss how I measured the angular separation of the planets. In other videos I discuss conjunctions, show my photos from August to November, and discuss why a Jupiter-Saturn conjunction occurs about every 20 years. See my Playlist of Astronomy General Interest to find these other videos. |
| Jupiter Saturn Conjunction 2020 Summary of Measurements | (5 minutes) This short video summarizes the photographs and measurements I made for the Jupiter-Saturn Conjunction of 2020. The video describes how I made the measurements and gives one slide with all of the measurement results. |
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| Unit 5 | ||
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