Volume 48 Number 1 JAAVSO 2020 The Journal of the American Association of Variable Star Observers Disk Instabilities Caused the 2018 Outburst of AG Draconis 2018 outburst of AG Draconis shown by STEPUP R-band and AAVSO R- and V-band measurements. The vertical dashed line marks the peak of the outburst, which occurred on JD 2458247.448. Also in this issue... • Continued Period Changes in BW Vulpeculae • HD 121620: A Previously Unreported Variable Star with Unusual Properties • Smartphone Astrophotography: A Useful Approach for Outreach and Education • 35,000 Radial Velocities for 348 Stars from the Tennessee State University Automatic Spectroscopic Telescope Complete table of contents inside... The American Association of Variable Star Observers 49 Bay State Road, Cambridge, MA 02138, USA The Journal of the American Association of Variable Star Observers Editor-in-Chief Editorial Board Nancy D. Morrison Geoffrey C. Clayton Vanessa McBride Professor of Astronomy Emerita Louisiana State University IAU Office of Astronomy for Department of Physics Baton Rouge, Louisiana Development; South African and Astronomy Astronomical Observatory; The University of Toledo, Kosmas Gazeas and University of Cape Town, Toledo, Ohio University of Athens South Africa Athens, Greece Associate Editor Ulisse Munari Elizabeth O. Waagen Laszlo L. Kiss INAF/Astronomical Observatory Konkoly Observatory of Padua Production Editor Budapest, Hungary Asiago, Italy Michael Saladyga Katrien Kolenberg Karen Pollard Universities of Antwerp Director, Mt. John Observatory, and of Leuven, Belgium University of Canterbury, and Harvard-Smithsonian Center Christchurch, New Zealand for Astrophysics Cambridge, Massachusetts Nikolaus Vogt Universidad de Valparaiso Kristine Larsen Valparaiso, Chile Department of Geological Sciences, Central Connecticut State University, New Britain, Connecticut The Board of the American Association of Variable Star Observers 2019–2020 Executive Director and CEO Stella Kafka President Gordon Myers Past President Kristine Larsen 1st Vice President Bill Stein 2nd Vice President Richard Berry Secretary Kristine Larsen Treasurer Robert Stephens Board Members Robert Buchheim Ken Hudson Michael Cook Bob Massey David Cowall Gregory R. Sivakoff Joyce A. Guzik Brad Vietje ISSN 0271-9053 (print) ISSN 2380-3606 (online) JAAVSO The Journal of The American Association of Variable Star Observers Volume 48 Number 1 2020 AAVSO 49 Bay State Road ISSN 0271-9053 (print) Cambridge, MA 02138 ISSN 2380-3606 (online) USA Publication Schedule The Journal of the American Association of Variable Star Observers is published twice a year, June 15 (Number 1 of the volume) and December 15 (Number 2 of the volume). The submission window for inclusion in the next issue of JAAVSO closes six weeks before the publication date. A manuscript will be added to the table of contents for an issue when it has been fully accepted for publication upon successful completion of the referee process; these articles will be available online prior to the publication date. An author may not specify in which issue of JAAVSO a manuscript is to be published; accepted manuscripts will be published in the next available issue, except under extraordinary circumstances. 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Miscellaneous: 1) Equations should be written on a separate line and given a sequential Arabic number in parentheses near the right-hand margin. Equations should be referred to in the text as, e.g., equation (1). 2) Magnitude will be assumed to be visual unless otherwise specified. 3) Manuscripts may be submitted to referees for review without obligation of publication. Online Access Articles published in JAAVSO, and information for authors and referees may be found online at: https://www.aavso.org/apps/jaavso/ © 2020 The American Association of Variable Star Observers. All rights reserved. The Journal of the American Association of Variable Star Observers Volume 48, Number 1, 2020 Editorial Dual-Anonymous Review Nancy D. Morrison 1 Variable Star Research QZ Carinae—Orbit of the Two Binary Pairs Mark Blackford, Stan Walker, Edwin Budding, Greg Bolt, Dave Blane, Terry Bohlsen, Anthony Moffat, Herbert Pablo, Andrzej Pigulski, Adam Popowicz, Gregg Wade, Konstanze Zwintz 3 A Note on Bimodal Pulsating Red Giants John R. Percy 10 The Photometric Period of Nova V2891 Cygni Richard E. Schmidt 13 The Reclassification of NSV 1586 from a Suspected Cepheid Star to a UG Class System Stephen M. Brincat, Charles Galdies, Kevin Hills, Winston Grech 16 Disk Instabilities Caused the 2018 Outburst of AG Draconis Helena M. Richie, W. M. Wood-Vasey, Lou Coban 21 Continued Period Changes in BW Vulpeculae David E. Cowall, Brian A. Skiff, Andrew P. Odell 28 ASAS-SN Observations of Long Secondary Periods in Pulsating Red Giants John Percy, Anthony Mark Wallace 31 HD 121620: A Previously Unreported Variable Star with Unusual Properties Roy A. Axelsen 35 CCD Photometry, Light Curve Modeling, and Period Study of the Overcontact Binary Systems NSVS 7245866 and V685 Pegasi Kevin B. Alton 40 Period Analysis of All-Sky Automated Survey for Supernovae (ASAS-SN) Data on a Sample of “Irregular” Pulsating Red Giants John R. Percy 50 The Photometric Period of V392 Persei (Nova Persei 2018) Richard E. Schmidt 53 Light Curve Asymmetries in Three Short Period Eclipsing Binary Stars Gage Hahs, Charlyn Ortmann, Vayujeet Gokhale 57 TYC 2402-0643-1: First Precision Photometric Observations and Analyses of the Totally Eclipsing, Solar Type Binary Ronald G. Samec, Daniel B. Caton, Danny R. Faulkner 62 Table of Contents continued on following pages Education and Outreach Smartphone Astrophotography: A Useful Approach for Outreach and Education Sara Bimo 72 Instruments, Methods, and Techniques A Gallery of Sky Brightness Curves from the January 2019 Total Lunar Eclipse Jennifer J. Birriel, J. Kevin