AAVSO 2022 How-to Discussions

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                                                                            [Go to 2022 How-to Hours]


December 3rd: 

"How to [Python! Visualizing MESA models with TULIPS]"

 with Dr. Eva Laplace  

Please note: This is the third session in a three-part series. Basic knowledge of Python is assumed. If you've never used Python before, you should install it and watch the recording of the first session ("The Basics") before attending this session. The second session, "Finding Frequency Solutions for Variable Star Light Curves" may also be helpful. 

In this third How to Python! broadcast, Dr. Eva Laplace will teach attendees how to use her Python package, TULIPS, to visualize MESA models. MESA models track the changing temperature, radius, composition, and structure of stars as they evolve, making them valuable tools for stellar researchers; but they are famously difficult to use. TULIPS makes it easy to visualize complex information, allowing you to create beautiful plots and animations showing the changes a star will undergo during its lifetime. Knowledge of basic Python is recommended. Attendees are encouraged to familiarize themselves with TULIPS ahead of time.

October 1st: 

"How to [Python! Finding Frequency Solutions for Variable Star Light Curves]"

 with Dr. Keaton Bell 

Please note: This is the second session in a three-part series. Basic knowledge of Python is assumed. If you've never used Python before, you should install it and watch the recording of the first session ("The Basics") before attending this session.

Many stars vary in brightness at one or many frequencies. Measuring these frequencies reveals valuable information about the physical properties of the observed systems. This tutorial demonstrates how to measure the frequencies (or periods) of variation in light curve data with the interactive Python package Pyriod. The tutorial will introduce periodograms, significance testing, and the iterative prewhitening algorithm for fitting signals to the data. Attendees will benefit from previous experience with light curves and Python, but this is not required to follow the presentation.


September 3rd: 

"How to [Python! The basics]"

 with Lauren Herrington 
Join us for an interactive session all about how to use Python for astronomy! We'll start by reviewing the very basics of Python, from variables to functions. Next, we'll cover simple usage of a few of the most popular packages for doing astronomy with Python, including live demonstrations of how to manipulate data using Astropy, make beautiful graphs using Matplotlib, and data mine massive remote datasets using Astroquery. This How to Python! session will feature even more interactivity than a typical How to Session, as our instructor, Lauren Herrington, will be taking questions throughout. As the first of three webinars in the AAVSO's How to Python! webinar series, this webinar will set the stage for broadcasts to follow on the topics of asteroseismology and stellar evolution models. Don't miss it!

August 6th: 

"0, 11, 12, 13… How to [‘Count’ Sunspot Activity]"

 with Dr. Kris Larsen 
The closest variable star, our sun, has begun to awaken from solar minimum, presenting observers with an ever-changing constellation of sunspots and other features. Following up on her popular 2021 webinar on how to safely observe the sun, Dr. Kristine Larsen returns to share the ins and outs of sunspot monitoring. Measuring sunspot activity takes more finesse than merely counting the total number of spots. Learn about the care and feeding of sunspot groups, and the important role they play in measuring solar activity.


June 4th: 

"How to [Think About Transformation]"

 with Tom Calderwood 
Astronomers have spent decades defining photometric "systems." Systems like Johnson-Cousins define a standard scale on which photometry from different observers can be directly compared. However, simply using a Johnson or Cousins filter does *not* put your magnitudes on the standard system. Your data require adjustment, and this step is known as transformation. In this discussion, Tom will explain why transformations are necessary, and sketch out the basics of how their parameters are determined.


May 7th: 

"How [my students and I do science with AAVSO Data--and How You Can, Too]"

 with John Percy 
Variable stars provide astronomers with unique and important information about the nature, evolution, and behavior of stars. AAVSO observers contribute mightily to this enterprise. For half a century, I have been engaged in variable star research, and in supervising and mentoring undergraduate research students, and even high school students. They can develop and integrate a wide range of science, math, and computing skills, motivated by the thrill of doing real science with real dataincluding AAVSO dataand publishing their results in journals such as JAAVSO. Skilled amateur astronomers can do this, too, whether they are observers or not! I will lead you through some of our projects using freely-available AAVSO data and, more recently, freely-available ASAS-SN data. You will learn about the particular strengths of these datasets, and about the complementary power of light curve analysis and time-series analysis, using the AAVSO VStar package. I will explain what we do, how, and why. And I will point out some of the science which can be doneby you and/or your students.

April 2nd: 

"How to [image star guts with cosmic music]"

 with Jim Fuller 
What lies at the center of a star? A stellar core is surrounded by a million Earths worth of plasma, so we cannot see it directly. However, the immense power of a star’s radiation causes nearly all stars to pulsate, creating “star quakes” at their surfaces. These oscillations are a collection of musical notes that uniquely define each star and are determined by its internal structure, just as the sound of a musical instrument is determined by its size and shape. Join me for a cosmic symphony as we journey to the center of the Sun, Saturn, white dwarfs, red giants, and heartbeat stars.


March 5th: 

"How to [Understand Star Photometry: How it Works]"
 with Richard Berry 
Photometry seems like magic: you click on a star image and a magnitude pops up! But a lot happens between the moment you "click" and the moment that magnitude pops up on the computer screen. Berry will explore with you--in non-technical terms--what the computer has to do to turn your pixels into meaningful information. This talk will complement Bob Buchheim's "Introduction to Photometry" 2021 webinar. Berry will describe how to do photometry by presenting the inside picture of how photometry works and why it works so well. He will demonstrate using AIP4Win software (join aip4win@groups.io to download this freeware package), but all stellar photometry software works pretty much the same way.


February 5th:

"How to [Observe Optical Counterparts of High Energy Astronomical Transients]"

 with Heinz-Bernd Eggenstein 
This presentation focuses on observing three of the most energetic and interesting phenomena in the universe: the Gamma-Ray-Burst (GRB) and its optical afterglow, the Binary Neutron Star (BNS) Merger resulting in a “kilonova,” and the Core-Collapse Supernova (and here specifically the next such event in our own galaxy).
At first glance, none of these three event classes seem to be well suited for the amateur astronomer because their first signals reaching us can only be seen by professional observatories: the Earth’s atmosphere shields us against gamma rays, so Gamma Ray Bursts are typically detected by satellites like FERMI and SWIFT. Binary Neutron Star Mergers so far can only be detected with high confidence by huge gravitational wave observatories. And, perhaps somewhat surprisingly, the very first signal of the next galactic core collapse supernova will actually be a burst of neutrinos, minutes to hours before the optical supernova signal can be seen.
However, in all three cases, professional astronomers broadcast “alerts” of such events through channels that are now available to the public, some more well known than others. We will discuss how amateurs can use these channels and join professional-amateur collaboration projects to make meaningful observations of these most fascinating events. While observing these transients remains challenging for various reasons, being prepared for “target of opportunity” observations should be a skill that can be rewarded by outstanding and important amateur observations.