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Uncertainty about Uncertainty (CHOICE)

Due to the New England winter storm currently affecting the area, phone coverage at the AAVSO may be much reduced until Wednesday. The staff is still available via email, and we suggest using that method to contact us if you need assistance.

This is a description of a CHOICE course.

This course is for photometric observers who want to learn how to make accurate estimates of the uncertainty (a.k.a. "error") of their observations. The only prerequisite is that the observer needs to have submitted photometric data to the AAVSO International Database. The course covers the theory behind uncertainty, the difference between precision and accuracy, the difference between stochastic and systemic uncertainty and includes a decision tree which an observer can use to determine what technique they should use to determine uncertainty for a given image. Examples are given using the AAVSO's free Vphot software, but students are free to use whatever software they prefer.

Here is a course outline:


1.     Introduction

2.     Signal vs. Noise

3.     Error vs. Uncertainty

4.     Accuracy vs. Precision

5.     Stochastic vs. Systematic

6.     Standard Error vs. Standard Deviation

7.     Quadrature

8.     Significant Figures

9.     Computing Photometric Uncertainty

o   Technique 1: Standard Deviation of the Variable

o   Technique 2: Standard Deviation of the Check Star

o   Technique 3: Standard Deviation of the Comparison Stars

o   Technique 4: Signal to Noise Ratio

o   Technique 5: CCD Equation

10.  Extra: History of Uncertainty in the AID

12.  Extra: Photometry Hints (Apertures, Ensembles and Binning)

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484