![Polarization axis scribing station developed for DragonflyPol. The setup enables repeatable transmission axis marking at better than 0.2◦ precision. Components include the QTH10 illumination source, Sloan r′ bandpass filter, pinhole, polarizing beamsplitter cube (reference axis), motorized rotation stage, and Hamamatsu photodiode readout.-- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/DragonflyPol.png?fit=1200%2C776&ssl=1)
[astro-ph.IM] We present DragonflyPol, a wide-field optical linear polarimetry capability implemented on the Dragonfly Telephoto Array. DragonflyPol leverages Dragonfly’s modular, multi-lens architecture to obtain simultaneous measurements in four linear polarization orientations (0∘, 45∘, 90∘, and 135∘) across a ∼5deg2 field of view, distributed across 44 polarized lens–detector units.
Four additional units serve as unpolarized reference channels. We describe a broad range of science goals enabled by this capability, including magnetic field mapping and tomography, dust grain properties, CMB foreground characterization, and the three-dimensional structure of diffuse interstellar clouds.
We integrate Canon polarizers and Baader Sloan r′ bandpass filters into the drop-in filter holders of the Canon lenses, and conduct a three-phase laboratory characterization program to select optimal polarimetric components, measure contrast ratios and transmission efficiencies, and determine and mark the transmission axis of each polarizer with sub-degree repeatability.
Laboratory measurements across all 44 deployed polarizers yield a mean noise-subtracted contrast ratio of 1228±104 and a single-polarizer transmission efficiency of ∼33% in the r′ band.
On-sky commissioning, including twilight flat-field characterization and twilight-sky polarization measurements, confirms throughput stability across polarization groups and successful recovery of the expected Rayleigh scattering signal. DragonflyPol achieved first polarimetric light in September 2025.
Mehrnoosh Tahani, Leo Hollberg, Hiroshi Akitaya, Jaeyeon Kim, Deborah Lokhorst, Roberto Abraham, Pieter van Dokkum, William P. Bowman, Vishwa Koshene Gamage, Paras Regmi, Yasuo Doi, Koji S. Kawabata
Comments: 17 pages, 11 Figures, submitted to PASP
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2607.14258 [astro-ph.IM] (or arXiv:2607.14258v2 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2607.14258
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Submission history
From: Mehrnoosh Tahani
[v1] Wed, 15 Jul 2026 18:13:40 UTC (6,183 KB)
[v2] Fri, 23 Oct 2026 22:38:31 UTC (6,183 KB)
https://arxiv.org/abs/2607.14258
Astrobiology,
