University of Nevada, Reno Photometry+: A Scientific Pipeline and Teaching Tool A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science and Engineering by Alexis R. Tudor Dr. Sergiu Dascalu / Thesis Advisor Dr. Richard M. Plotkin / Thesis Advisor May, 2021 Copyright © 2021 by Alexis R. Tudor All rights reserved. THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by ALEXIS TUDOR entitled Photometry+: A Scientific Pipeline and Teaching Tool be accepted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Sergiu Dascalu, Ph.D. Advisor Richard M. Plotkin, Ph.D. Co-advisor Emily M. Hand, Ph.D. Committee Member Melodi Rodrigue, Ph.D. Graduate School Representative David W. Zeh, Ph.D., Dean Graduate School May, 2021 i Abstract As more and more data are collected from the night sky, it becomes increasingly important to be able to analyze the data precisely and quickly by using computer programs. Given the importance of data analysis pipelines for telescopes we have developed a photometric pipeline, Photometry+, for the Great Basin Observatory (GBO), a 0.7-meter robotic telescope located in the Great Basin National Park in Nevada. This photometric pipeline takes raw images of the night sky and measures the magnitude of a star in the image. Studying the changes in the flux of a star over time is crucial for learning more about variable objects such as supernovae and binary star systems. Photometry+ focuses on human-computer interaction (HCI) in addition to scientific results. The HCI goals of the proposed pipeline are to create a graphical user interface (GUI) that is easy to use, gives astronomers control of and confidence in the results of the program, and teaches students the process of differential photometry through use. Our research shows that users agree that these goals are met and that just using Photometry+ results in a statistically significant 15% increase in score on a differential photometry quiz (from 66% to 81%). These results cement it as a new tool for professional astronomers looking to reduce the time they spend on data analysis while still obtaining publication-quality results and for students looking to learn the process alike. This thesis encompasses astronomy and human-computer interaction background, related works, software engineering aspects, practical astronomy uses of Photometry+, the user study research we completed, and the results we obtained. ii Dedication To my parents, Glenn and Judy Tudor, and my partner, Ryan Nunes for their endless support of me during the challenging times in which this work was created. Additionally I would like to dedicate this work to my Chihuahua, Lucky, who was there for me for most of my education and passed away in 2020. iii Acknowledgements I would like to thank from the bottom of my heart the advisors over this work, Dr. Sergiu Dascalu and Dr. Richard Plotkin, as well as Dr. Aarran Shaw, for their invaluable support and near-infinite knowledge, without which this research would never have come to completion. Additional thanks to the Great Basin Observatory, Nevada, for their support of this project and the use of their telescope, with particular thanks to Aviva O’Neil for all of her help. And finally, great thanks to the UNR Black Holes lab group, whose brainstorming ability and willingness to help was critical to making Photometry+ what it is. iv Table of Contents Abstract i Dedication ii Acknowledgements iii Table of Contents iv List of Tables viii List of Figures ix 1 Introduction 1 2 Background 4 2.1 Photometry and Differential Photometry 4 2.2 Astronomy and Computing 6 2.2.1 Novae 7 2.2.2 Intermediate Polars 9 2.2.3 Black Hole X-Ray Binary Systems 11 2.3 Interactive Systems 12 2.3.1 User Experience Design 14 3 Related Works 15 3.1 Photometric Pipelines 15 3.2 User-Friendly Design in Scientific Software 16 3.3 Discussion 17 4 Photometry+: Software Engineering Aspects 19 4.1 Software Specifications 19 4.1.1 Discovery 19 4.1.2 Functional Requirements 21 v 4.1.3 Non-Functional Requirements 24 4.2 Technical Specifications 25 4.2.1 PyQt5 25 4.2.2 Astrophysics Libraries 26 4.2.3 VizieR, SIMBAD, and Astrometry.net 27 4.3 System Design 27 4.3.1 User Interface Design 29 4.4 Development 30 4.4.1 Test-Driven Development 30 4.4.2 Iterative Development 34 4.4.3 Development User Studies 36 4.4.4 Agile Development 36 4.5 Data Design 37 4.6 Documentation 38 5 Scenarios of Use 39 5.1 Code Version 39 5.1.1 Use Cases 40 5.2 Desktop Version 42 5.2.1 Use Cases 42 5.2.2 Home 44 5.2.3 New Project 44 5.2.4 Processing and Walkthrough Mode 48 5.2.5 Project Results 51 5.2.6 My Projects 52 vi 5.2.7 About 52 5.2.8 Settings 53 5.2.9 FAQ 54 6 Practical Astronomy Applications 56 6.1 Light Curve Analysis of Transient Nova AT2019tlu 56 6.2 Monitoring For Rare Low-Flux States of Intermediate Polars 58 6.3 Teaching Stellar Evolution with a Generated CMD 61 6.4 Studying the A0620-00 Black Hole X-Ray Binary System 62 6.5 Planned Observing Projects 64 7 User Studies 65 7.1 Participants 65 7.1.1 Age 66 7.1.2 Gender 66 7.1.3 Education Level 67 7.1.4 Operating System 68 7.1.5 Astronomy Experience Level 68 7.1.6 Photometry Experience Level 69 7.2 Apparatus 70 7.3 Procedure 70 7.3.1 Pre-Study Survey 71 7.3.2 Differential Photometry Quiz 72 7.3.3 Photometry+ Tasks 73 7.3.4 Post-Study Survey 74 7.4 Experimental Design 76 vii 8 Results and Discussion 77 8.1 Results of Post-Study Survey 77 8.2 Analysis of Dependent Variable Derived From Quiz 79 8.3 Discussion 79 9 Conclusions and Future Work 81 Appendix A 83 Appendix B 84 References 86 viii List of Tables Table 4.1: Functional requirements for Photometry+ versions, where C indicates the code version and D indicates the desktop application. 22 Table 4.2: Non-functional requirements for Photometry+ versions, where C indicates the code version and D indicates the desktop application. 24 Table 4.3: Example subset of tests used for test-driven development along with most recent results. 31 Table 5.1: This table describes the use cases in Figure 5.1 in more detail. 40 Table 5.2: Detailed descriptions of the use cases described in Figure 5.2. 43 Table 8.1: Results of post-study survey Likert scale questions. In all of the examples below, the scale starts at “Strongly Disagree” at one and ends at “Strongly Agree” at five. 78 ix List of Figures Fig. 1.1: The Great Basin Observatory, Nevada. Photo Credit: The Great Basin Observatory. 1 Fig. 2.1: Artist’s depiction of a cataclysmic variable, with white dwarf in the bottom left and the donor star in the top right. Art credit: Julie Bauschardt. 10 Fig. 2.2: The Xerox Star (left) and its GUI (right). Photo credit: The Interface Experience. 13 Fig. 4.1: The context diagram for Photometry+ displaying the external dependencies of the system. 26 Fig. 4.2: Abridged version of the steps Photometry+ takes to perform differential photometry. 28 Fig. 4.3: Light curve made with Photometry+ utilizing GBO data (top) matched with data from AAVSO, where the Photometry+ results are green and AAVSO results are blue (bottom). The match in the bottom figure demonstrates that Photometry+ works with a comparable accuracy to other top photometric pipelines. Figure generated by Ava Covington. 29 Fig. 4.4: A diagram showcasing the iterative development stages used for all parts of coding Photometry+. 34 Fig. 4.5: Three example screens of Photometry+ prototypes, with the desktop versions on top and the website version on the bottom. 35 Fig. 5.1: Use cases for the code version of Photometry+. 40 Fig. 5.2: Use cases for the desktop version of Photometry+. 42 Fig. 5.3: The Home screen of the desktop version of Photometry+. 44 Fig. 5.4: The New Project page of Photometry+ before any user input. 45 Fig. 5.5: The New Project page of Photometry+ after being filled out by the user. 45 Fig. 5.6: Demonstration of the tooltip associated with the catalog setting. 46 Fig. 5.7: Demonstration of the pop up window associated with clicking on the information button next to the catalog setting. 47 Fig. 5.8: Confirmation prompt after user tries to submit their project. 47 Fig. 5.9: Initial processing screen after a new project is submitted. 49 x Fig. 5.10: Walkthrough mode reference star selection with all reference stars checked. 49 Fig. 5.11: Walkthrough mode reference star selection with Ref6 and Ref20 unchecked. 50 Fig. 5.12: Processing screen after reference stars are confirmed. 50 Fig. 5.13: Project results page for a DO Dra project. 51 Fig. 5.14: Project management page for Photometry+. 52 Fig. 5.15: The About page of Photometry+, broken into three of the scrollable sections in order. 53 Fig. 5.16: The default settings page of Photometry+. 54 Fig. 5.17: Frequently asked questions page of Photometry+. 55 Fig. 6.1: This photometry data shows the star AT2019tlu. This image is made of the data from the B, V, and R filters of the Great Basin Observatory, and AT2019tlu is circled.