2020 How-to-Hour

This “How-to Hour” presentation is designed to provide a discussion of principles, procedures and skills that can be understood and utilized by amateurs to advance their practice of variable star photometry. It is presented by experienced observers who will describe the techniques needed to answer questions that all of us may ask and struggle with when advancing through our avocation.

A Biased Guide to Giving Science Talks – Gregory Sivakoff

We all know that some speakers give incredible and engaging talks, while other speakers have a harder time connecting with their audience. Like many things in life, the key to excelling at giving a good science talk is not relying on innate skills. Instead, it requires planning, knowing some good rules of thumb, some attention to detail, and practice. I hope that my biased guide to giving science talks will help you become a better, more engaging speaker, while (perhaps) reducing some of the stress of speaking in public. Most importantly, I hope that we can start a continuing discussion on how we all at AAVSO can become better speakers, myself included.

Photometric Accuracy of Amateur Systems – Ken Menzies and Edward Wiley

Photometrists repeatedly ask how accurate their magnitudes are using typical amateur-level equipment. We describe methods to evaluate accuracy by imaging Standard Fields in multiple filters; using VPhot/LesvePhotometry to conduct differential photometry, applying ensemble photometry, and/or applying transformation to reduce the data, and to compare the bias (accuracy) of measured magnitudes versus Landolt Standards.

We address two major questions concerning differential photometry: (1) Does accuracy improve when multiple comparison stars (single comp versus ensemble) are used for magnitude calculation, and (2) Does accuracy improve when magnitudes are color transformed to the standard system.

We report the following results and observations: (1) Landolt Standard Fields provide effective analysis of accuracy of photometric systems. (2) VPhot, LesvePhotometry & Excel Tools facilitate analysis. (3) Differences between Observed and Known Magnitudes (O-K) are statistically improved by transformation. (4) Differences are not always statistically significant between single-comp and ensemble O-K accuracy; but we note a consistent improvement in precision that favors the ensemble approach, (5) With careful processing the difference between CCD/CMOS camera magnitudes and known Landolt standards are small and within experimental error, and (6) As expected, selection of proper Comp SNR, Photometric Aperture; Image Quality impacts experimental error and bias. The typical error achieved by amateur systems confounds the ability to statistically confirm their accuracy.

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