AC4.1.1. Distance to Asteroid1998wt

{ A Changing Cosmos Contents } { All GSS Books } by Rich Lohman Materials Image Processing software such as JS (online app) – https://js9.si.edu JS9-HOU – https://hou-js9plugins.educontinuum.org SalsaJ available from European HOU site Images : asteroid1998wt.zip  (4.2 Mb; FITS) asteroid1998wtJPGs.zip  (840 Kb) Introduction On March 4, 2005, telescopes from two different observatories in the United […]

AC4.5. A Cepheid Variable Star

Investigation AC4.5 { A Changing Cosmos Contents } Materials I. Plotting the Light Curve for a Cepheid A Cepheid was monitored for a 15-day time span, but on only eight of those nights were the skies clear enough to get good images. You are to measure the brightness of the star on each image and […]

AC4.4. Star Magnitudes

{ A Changing Cosmos Contents } { All GSS Books } Image Processing software such as JS (online app) – https://js9.si.edu JS9-HOU – https://hou-js9plugins.educontinuum.org SalsaJ available from European HOU site Image: Mgclust.fts Materials I. The Magnitude Scale Using magnitude scale definitions on the previous page, the following  are examples of determining how many times brighter one […]

AC4.3. A Law of Brightness

{ A Changing Cosmos Contents } { All GSS Books } A basic physics lab activity using a light sensor to measure brightness of light source(s) at various distances.  Materials: Computer light sensor or Photo cell and ohmmeter Light bulb(s) Meter stick What to do: Hook the photocell to the ohmmeter, and check that the […]

AC4.2. Distance to the Moon Using Parallax

{ A Changing Cosmos Contents } { All GSS Books } Overview: We’ll observe and measure the parallax angle of a relatively distant object, such as a tree or a flagpole, and use that angle  to determine the distance to the object. Geometrically, parallax shift for the Moon can be represented by this diagram: Points […]

AC4.1. Parallax

{ A Changing Cosmos Contents } { All GSS Books } There are also 4 other investigations associated with this investigation: Overview: To see how parallax works, we’ll observe and measure the parallax angle of a relatively distant object such as a tree or a flagpole and use that angle  to determine the distance to […]

AC4. Fathoming Huge Distances

Chapter 4 { A Changing Cosmos Contents } I. Distance To Things in Our Solar System  For relatively nearby things, like airplanes, we can use radar waves to measure how far away they are. Radar waves are like the radio waves that  radios, wi-fi, and TVs operate with.  Air traffic controllers at airports use radar […]

AC3.3. Sun Movement

{ A Changing Cosmos Contents } { All GSS Books } Originally: The Position of the Sun During the Day (A Partial Explanation for the Seasons)  [see also The Solar Calendar] In this investigation you use the software Stellarium to take data of the Sun’s position over a period of a day.  You’ll take the […]

AC3.2. Plate Scale of a Smartphone

Investigation 3.2 { A Changing Cosmos Contents } Materials One of the image processing (IP) apps listed for A Changing Cosmos on the GSS software page. Steps I. In order to look at “Smartphone” images with SalsaJ or JS9, you need to be able to transfer photos from your smartphone to your computer and know where to […]

AC3.1. Size and Scale of the Sun

Investigation 3.1 { A Changing Cosmos Contents } Materials:  I. How Big is that Prominence? a. Use Image Processing app/software to open the image eclipse1.fts.   This image of the longest total solar eclipse* of the 20th century was taken in Hawaii in 1991 by an HOU team. Look around the rim of the Sun (often called […]