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CHOICE Course Descriptions

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Most courses are available to AAVSO members AND the general public. The fee for AAVSO members is $35.00 click here. Non-members pay $60.00 click here. Registrations are available on a first-come, first-served basis.

The following is a brief description of each course currently offered in the CHOICE curriculum:


CCD Photometry Part I

This course will use the first half of the AAVSO Guide to CCD Photometry and will provide motivation and scientific background for doing photometry with a CCD.  Topics covered include system testing and basic image calibrations from bias and dark frame subtraction to flat fielding. Students will need their own image processing software, and should have their own CCD/telescope ready to take calibration and light frames. A cooled monochrome camera is required. A cooled 16-bit monochrome CCD is recommended. One-shot color cameras are not suitable for this particular course.

Important-please read: Camera and software requirements and recommendations


CCD Photometry Part II

This course covers chapters 5, 6, and 7 of the AAVSO CCD Photometry Guide.
Prerequisites: Experience with basic CCD imaging and image calibration.  CCD Photometry (Part I) is strongly advised but not required.  

This is an observing course.  You must have the use of a functioning telescope and camera system and the ability to produce calibrated images of assigned fields.  You will need, at minimum, a photometric Johnson V filter, and one other photometric filter, preferably Johnson B.  For observers transitioning from RGB tricolor imaging, you may use your RGB filters for the exercises, including transforms, but you will need photometric filters if you decide to continue doing CCD photometry.    

You will also need working knowledge of the photometry tool in any of the standard CCD image processing programs.  Knowledge of VPhot will be very helpful.  

For students continuing from CCD Photometry (Part I), detailed instructions on how to do the exercises using VPhot will be provided.  By the end of the course you should have a decent working knowledge of VPhot.

Important-please read: Camera and software requirements and recommendations


Developing A Visual Observing Program

This four week course is designed to help visual observers get the most enjoyment and scientific return from the observing programs they develop, based on each individuals’ equipment, observing conditions and interests. To successfully complete this course you must provide in writing, two documents.

1) A complete observer profile (a sample is provided)

2) A list of stars appropriate for your primary observing equipment, observing site and conditions, frequency of observing sessions, scientific merit and fun factor (a sample is provided).


DSLR Photometry

This course will utilize the AAVSO DSLR Observing Manual as its guide. This manual is a basic introduction and guide to using a DSLR camera to make variable star observations. The target audience is first-time beginner to intermediate level DSLR observers, although advanced observers may find the content useful as well.

Important-please read: Camera and software requirements and recommendations


Exoplanet Observing

This course is designed to provide participants with the basics of how to conduct their own exoplanet observations. With the scheduled launch of TESS (Transiting Exoplanet Survey Satellite) in March 2018, this course offering is especially timely.

The first half of the course will cover the fundamentals of high precision photometry, as well as the various phases of an exoplanet observation. The second half will review the use of AstroImageJ (AIJ) for image reduction and exoplanet transit modeling. In addition, the future of exoplanet observing using small telescopes will be discussed, as well as ways in which amateur astronomers can contribute to exoplanet research, including contributions to the TESS mission.

The course will use “A Practical Guide to Exoplanet Observing” as its primary text, as well as a set of sample exoplanet observations, both of which can be found at Video modules will lead participants through each part of the course and participants will be required to take a quiz after each module.

Participants must successfully pass each quiz to successfully pass the course. A private forum will be available to participants in order to communicate with each other, as well as the instructor.


Photoelectric Photometry in the 21st Century

This course will cover the techniques necessary for observers to produce highly accurate variable star observations using single channel photometric photometry (PEP).  We will cover the history of PEP technology and its continuing relevance today, as it fills a gap left by CCD and large automated surveys for precision photometry of bright stars.

Equipment and observing techniques will be presented as well as detailed discussions of data reduction and error source identification and correction.  Spreadsheet based tools for extinction, transformation, and data reduction to the standard system will be provided for use in labs using sample observation sets.  Specific techniques applicable to commercially available single channel photometers, such as the Optec SSP-3 and SSP-5 will be covered in detail.

Although this material and the exercises will be based on PEP observations, the underlying theory is applicable to all types of photometric measures, and may prove useful to CCD and DLSR observers who desire a fundamental understanding of photometric measurement.

The course will conclude with a module on designing your own PEP observation program.  Star and observation band selection will be covered, as well as discussions on how to balance the calibration observations needed for high precision with the science observations that are the final results.

The course will use the newly created Photoelectric Photometry Observing Manual as its primary text, but will augment this material with additional readings and tools available on the AAVSO website.

You must successfully complete exercises and weekly quizzes as well as a final examination to pass the course.


Photometry Using VPHOT

This course is designed to teach observers how to use VPHOT, the AAVSO’s cloud based photometry reduction software. You will learn how to upload and manage your image files, how to perform photometry on single images and time series, how to save your analyses and how to submit your results to the AAVSO. You do not have to own a CCD or have your own images. Sample images will be provided.

An extra week has been added to this course in order to add transformations to the curriculum.

You must successfully complete exercises and weekly quizzes as well as a final examination to pass the course.

This course is only available to AAVSO members. If you would like to join the AAVSO click here.


Variable Star Classification and Light Curves

This course is an overview of the types of variable stars most commonly observed by AAVSO observers. We discuss the physical processes behind what makes each type variable and how this is demonstrated in their light curves. Variable star names and nomenclature are placed in a historical context to aid in understanding today’s classification scheme.

You must successfully complete weekly quizzes, a journal paper review and a final examination to pass the course.


Visual Observing Basics

This course will use the AAVSO Visual Observing Manual as its primary text. We will cover variable stars, basic equipment, how to make observations and submit data, plotting VSO charts, planning an observing session and many other topics. This course is highly recommended for anyone just starting out in visual VSOing.

The course will last four weeks. There will be an additional two-week period in which to make observations, submit observations, ask questions in the forum and put what you’ve learned into practice. After the six-week period, those who have completed the quizzes, participated in discussions and submitted two positive variable star observations of sufficient quality to the AAVSO International Database will be awarded a certificate of accomplishment along with a badge on your website profile.


How to use VStar

This course is intended to provide participants with a systematic coverage of VStar's current functionality, an appreciation of the ways in which it can be extended, and how it can be used for variable star data visualization and analysis.

You’ll learn how to create mean plots, phase plots, and perform simple period analysis. This is not a course on statistics but relevant statistical concepts as they apply to the use of VStar will be introduced through reading and discussion.

You must successfully complete exercises and weekly quizzes as well as a final examination to pass the course.

VStar is written in the Java programming language, requiring at least version 1.6 to run on Windows, Mac OS X, Linux, and OpenSolaris.


Analyzing Data with VStar

This course is intended for VStar users who have taken and passed the basic CHOICE VStar Course, How to Use VStar. This course assumes that you already know the mechanics of using VStar. The objectives of this course are to provide participants with a better understanding of analysing data with VStar, what you are doing when you use VStar and why it works. That means the course explores basics of underlying theory, limitations of the analysis and valid conclusions one can draw from the results and conclusions that one cannot draw from the results.  The course will also afford ample practice in applying the various analytical tools VStar provides.

This will be achieved by guided reading, exercises (both illustrative and real-world), forum discussions, quizzes, and a final exam or project. The text for the course is Analyzing Light Curves: A Practical Guide, by Grant Foster, which will be applied to the use of VStar. The book is available from and is required for the course (Please order your book at least 2 weeks before the start of the course.)

Discussion topics will be created in the course forum for all major course outline sections. Everyone can benefit from questions and comments in such forum topics.

This is not a course on statistics but relevant statistical concepts as they apply to the use of VStar will be introduced through reading and discussion. By necessity this course will use more math than the basic course.


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