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Roger M. Hart

Publications and source records attributed to Roger M. Hart.

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The Local Sky as an Introductory Solar System Astronomy Laboratory Using Smart-Telescopes

Portable smart telescopes can make introductory astronomy more observational, quantitative, and locally grounded by allowing students to acquire, share, and analyze astronomical images within a single class period. This article presents an eight-laboratory sequence for introductory Solar System astronomy using the Seestar S50 smart telescope and archived or student-collected images. The sequence begins with a galaxy-size investigation that introduces pixel scale, angular size, physical size, proportional reasoning, and measurement uncertainty before students apply the same image-to-evidence approach to Solar System objects. Subsequent activities examine the positions and apparent motion of Jupiter's Galilean moons, comparative planetology and telescope limitations, the apparent sizes of Mars, Jupiter, and Saturn, lunar phase and angular diameter, relative lunar surface history through crater-density comparisons, single-session solar activity, and multi-day sunspot tracking to estimate solar rotation. Each investigation follows a 5E-informed structure and produces a focused student product, such as a measurement table, graph, comparison chart, or claim-evidence-reasoning statement. Throughout the sequence, students must define transparent measurement rules, distinguish direct observations from interpretations, and evaluate how image scale, illumination, exposure, seeing, target visibility, and boundary selection constrain their conclusions. The activities are designed for high-school, dual-enrollment, community-college, and introductory university astronomy courses and may be implemented with live observations or prepared image sets when weather, scheduling, or local observing conditions prevent data collection.

physics.ed-ph

Null Results, Real Learning: Geomagnetic Response to an X1.8 Solar Flare with Research-Grade and Smartphone Magnetometers in a Citizen-Science Classroom Activity

Introductory college Earth and space science courses offer rich opportunities for citizen science projects. One especially compelling context is Earth's geomagnetic field: a self-excited dynamo in the liquid outer core generates a global field that couples Earth's interior to solar forcing, providing a natural laboratory for space weather education. We tested the viability of smartphone magnetometers for quantitative monitoring during the 4 November 2025 X1.8 solar flare, linking planetary magnetism, space weather, and authentic undergraduate research. Co-located observations were obtained with a Geometrics G-857 proton-precession magnetometer and tri-axial smartphone sensors logging via Physics Toolbox in a course-based undergraduate research experience (CURE) emphasizing the Nature of Science (NOS). Fourteen one-minute paired averages spanning 17:27-17:40 UT revealed a systematic smartphone bias of about 630 nT (95% confidence interval 550-710 nT) relative to the G-857 and a weak negative correlation (r ~ -0.4). Smartphone magnetometers thus lack the precision and calibration stability needed for nanotesla-scale flare signatures but remain valuable as pedagogical and engagement tools. We frame smartphones within a tiered instrumentation ladder linking research-grade observatories, intermediate-cost community magnetometers (for example, HamSCI Personal Space Weather Stations), and smartphones as high-engagement entry points to geomagnetic and space weather studies. This hierarchy aligns citizen science with open data protocols and NOS pedagogy, transforming low-cost sensing into epistemically grounded inquiry suitable for introductory college laboratories.

physics.ed-ph