MIDSSAR: MId Dispersion Spectrograph for Stellar Activity Research

Abstract

We have developed and commissioned MIDSSAR (MId Dispersion Spectrograph for Stellar Activity Research), a novel fiber-fed, dual-band spectrograph optimized for high-cadence monitoring of stellar superflares and magnetic activity phenomena, mounted on the 3.8-m Seimei Telescope at Kyoto University Okayama Observatory. Utilizing a custom-designed volume phase holographic grating and a commercially available volume binary transmission grating, the instrument achieves simultaneous observations of key chromospheric activity indicators: the CaII H&K band (382.5-406.5nm) at a resolving power of R=13,800, and the Hα band (641.1-667.6nm) at R=18,200. MIDSSAR is strategically integrated with the existing high-dispersion spectrograph GAOES-RV to enable concurrent photosphere-chromosphere monitoring. The control software coordinates high-speed dual-camera exposures down to 1ms while incorporating real-time telescope telemetry into the data headers. We also developed a dedicated data reduction pipeline that automatically executes calibration, spatial reconstruction of the 61-fiber bundle, and one-dimensional spectral extraction with a wavelength precision of ∼ 0.002nm. Initial on-sky test observations conducted from March to May 2026 successfully verified the system's quantitative readiness. The observed signal-to-noise ratio characteristics perfectly align with modeled theoretical limits under varying seeing conditions, confirming that the entire instrument complex successfully meets its primary design requirements and operational expectations for systematic stellar astrophysics surveys.

Calibration of the Next Generation Palomar Spectrograph as a Stellar Speedometer
Pranav Nagarajan, Kareem El-Badry
arXiv16 Oct 2026PreprintCC BY 4.0Full textGalaxies Instrumentation & methodsarXiv
KiDS J1447-0149: The first spatially resolved spectroscopy of a relic galaxy beyond the local universe. An old high-dispersion core embedded in a compact rotating stellar structure
Johanna Hartke, Chiara Spiniello, Michele Cappellari +13
arXiv18 Sep 2026PreprintarXiv licenceFull textGalaxiesarXiv
"Mega-Earths" are likely an artifact of stellar activity
Casey L. Brinkman, Nicolas Cowan
arXiv8 Oct 2026PreprintarXiv licenceFull textInstrumentation & methods Planetary science & exoplanetsarXiv
Evolution of Stellar Activity and Habitable Zone. IV. Calcium II Infrared Triplet Activity from Open Clusters and White Dwarf Binaries
Shidi Zhang, Song Wang, Henggeng Han +1
The Astrophysical Journal2 Nov 2026Peer-reviewedCC BY 4.0Full textSolar & stellar physicsIOP/AASCrossref
Evolution of Stellar Activity and Habitable Zone (EATEN): III. X-ray Activity of Dwarfs in Open Clusters and Field Stars
Xue Li, Song Wang, Henggeng Han +3
arXiv29 Aug 2026PreprintCC BY 4.0Full textPlanetary science & exoplanets Solar & stellar physicsarXiv

Cite

BibTeX RIS

BibTeX

@misc{iwamuro2026midssar,
  title = {{MIDSSAR: MId Dispersion Spectrograph for Stellar Activity Research}},
  author = {Fumihde Iwamuro and Daisaku Nogami and Hiroyuki Maehara and Masaru Kino and Kai Ikuta and Akito Tajitsu and Sanghee Lee and Miho Kawabata and Keisuke Isogai and Kenta Taguchi and Kazunari Shibata},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.22834},
  eprint = {2610.22834},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.22834},
}

RIS

TY  - UNPB
TI  - MIDSSAR: MId Dispersion Spectrograph for Stellar Activity Research
AU  - Fumihde Iwamuro
AU  - Daisaku Nogami
AU  - Hiroyuki Maehara
AU  - Masaru Kino
AU  - Kai Ikuta
AU  - Akito Tajitsu
AU  - Sanghee Lee
AU  - Miho Kawabata
AU  - Keisuke Isogai
AU  - Kenta Taguchi
AU  - Kazunari Shibata
PY  - 2026
DA  - 2026/10/16
PB  - arXiv
DO  - 10.48550/arxiv.2610.22834
UR  - https://arxiv.org/abs/2610.22834
AB  - We have developed and commissioned MIDSSAR (MId Dispersion Spectrograph for Stellar Activity Research), a novel fiber-fed, dual-band spectrograph optimized for high-cadence monitoring of stellar superflares and magnetic activity phenomena, mounted on the 3.8-m Seimei Telescope at Kyoto University Okayama Observatory. Utilizing a custom-designed volume phase holographic grating and a commercially available volume binary transmission grating, the instrument achieves simultaneous observations of key chromospheric activity indicators: the CaII H&K band (382.5-406.5nm) at a resolving power of R=13,800, and the Hα band (641.1-667.6nm) at R=18,200. MIDSSAR is strategically integrated with the existing high-dispersion spectrograph GAOES-RV to enable concurrent photosphere-chromosphere monitoring. The control software coordinates high-speed dual-camera exposures down to 1ms while incorporating real-time telescope telemetry into the data headers. We also developed a dedicated data reduction pipeline that automatically executes calibration, spatial reconstruction of the 61-fiber bundle, and one-dimensional spectral extraction with a wavelength precision of ∼ 0.002nm. Initial on-sky test observations conducted from March to May 2026 successfully verified the system's quantitative readiness. The observed signal-to-noise ratio characteristics perfectly align with modeled theoretical limits under varying seeing conditions, confirming that the entire instrument complex successfully meets its primary design requirements and operational expectations for systematic stellar astrophysics surveys.
ER  -

Abstract

Related

Cite