3A

A) Introduction
*Note to Leaders/Teachers: Please see the resources “For IDATA” Section 3 for notes and Journal answers.
Let’s do a quick REVIEW of Section 1 and Section 2:
SECTION 1
– focused on using Quorum to command Skynet to request CCD camera images of objects in space.
SECTION 2
– focused on understanding and using the software, Afterglow Access, to examine one, or at most, two images at a time.
What will SECTION 3 teach us?
This section will focus on gathering data from an image to measure an object’s brightness (the apparent magnitude). We will then see how computers are used to analyze and display the data – in this case, a light curve. Afterglow Access will provide most of the tools we need.
**REVIEW Questions**
In Section 2, you found the rotational period of a model asteroid (recall the potato). In the JOURNAL below, answer the following two questions.
1. Without looking back, write a definition for rotational period.
2. Then, briefly describe what information you would need to find the rotational period of a REAL asteroid (Hint: look at the goals of section 3 below the journal box).
JOURNAL BOX
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Chris introduces Section 3 in this 3:23 video.
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You have already learned to do a lot of astronomy. Congratulations! You can
1. Request images of an object (Section 1)
2. Locate an asteroid in an image (see Part Q of Section 2)
3. Use Quorum commands on matrices to model how image processing software works behind the scenes.
Let’s now tackle the following goals
Section 3 GOALS:
1. You will learn about apparent magnitude and how it relates to the idea of photometry.
2. You will learn about the different types of photometry and which type is appropriate to measure the brightness of an asteroid.
3. You will compare the brightness of an asteroid to the brightness of a well-known source called a standard star using a math equation in Quorum.
4. Using Afterglow Access, you will learn how to photometer an asteroid and standard star across a series of images taken during one night.
5. You will learn how to download and interpret this photometry data from Afterglow Access. Apparent magnitude shows up in this data.
6. You will then construct a graph of the change in brightness (apparent magnitude) vs time for your series of asteroid observations. This graph is the light curve of the asteroid.
7. You will then interpret the light curve of your asteroid to find and verify its rotation period.
Let’s get started!

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