Satellite Streaks in HETDEX: Spectra, Orbital Identification, and Survey Impact

Abstract

We present a spectroscopic database and analysis of satellite streaks in Public Data Release 1 (PDR1) from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), covering 6778 observations and $\sim$90 deg${}^2$ of sky from January 2017 to July 2024. We detect 527 streaks across 492 observations, a contamination fraction of 7.3% that rises to monthly values above 20% by 2023--2024, although the streaks mask only 0.09% of the survey area. Of the 527 streaks, 475 (90.1%) are identified with a cataloged object using archival two-line elements: 258 (54%) lie in low or Earth orbit and 217 (46%) are geostationary or highly elliptical. Only 35% were launched since 2010; the rest are spent rocket bodies, debris, and older spacecraft. This reflects HETDEX's sensitivity to faint objects and its 2017--2024 observing baseline. The Hobby-Eberly Telescope's large 10\,m aperture and HETDEX's $\sim$6\,minute exposures result in similar observed magnitudes for low Earth orbit (LEO) and geostationary Earth orbit (GEO) objects (median $g_{\mathrm{AB}}=16.2\pm 1.1$ for LEO, $16.7\pm 1.1$ for GEO). However, once transit time is corrected for, instantaneous magnitudes differ widely: $g_{\mathrm{inst}}=7.4$ for LEO versus $g_{\mathrm{inst}}=13.0$ for GEO objects, a difference of 5.6\,mag, while the exposure-averaged magnitudes differ by only 0.5 mag. Normalized to 550 km, the 34 Starlink streaks give $g(550\mathrm{km})=5.95$, consistent with the mean $V(550\mathrm{km})=5.92\pm 0.04$ reported for VisorSat-design spacecraft. The spectra are consistent with reflected sunlight, with modest, signal-to-noise-driven differences in slope. The catalog, spectra, and code are archived at https://doi.org/10.5281/zenodo.22962479.

arXiv comment15 pages, 5 figures, 1 table. Published at Mentuch Cooper et al., 2026, AJ, 172, 303. Data available at https://doi.org/10.5281/zenodo.22962479. Full workflow at https://github.com/eriniocentric/hetdex_sats

References in corpus (14)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Overview of the DESI Legacy Imaging Surveys
• The Low Earth Orbit Satellite Population and Impacts of the SpaceX Starlink Constellation
• The HETDEX Instrumentation: Hobby-Eberly Telescope Wide Field Upgrade and VIRUS
• The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections
• On the Impact of Satellite Constellations on Astronomical Observations with ESO telescopes in the Visible and Infrared Domains
• Mitigation of LEO Satellite Brightness and Trail Effects on the Rubin Observatory LSST
• astroplan: An Open Source Observation Planning Package in Python
• HETDEX Public Source Catalog 1: 220K Sources Including Over 50K Lyman Alpha Emitters from an Untargeted Wide-area Spectroscopic Survey
• The HETDEX Survey: Emission Line Exploration and Source Classification
• HETDEX Public Source Catalog 1 -- Stacking 50K Lyman Alpha Emitters
• Satellite Constellation Internet Affordability and Need
• HETDEX Public Data Release 1: Source Catalog 2 and Data Cubes from ~90 sq deg of Integral-Field Optical Spectroscopy