[論文レビュー] Observations of Binary Stars with the 1.3-m Devasthal Fast Optical Telescope Using Speckle Interferometry: An Attempt

Km Nitu, Arjun Dawn+4 more|arXiv (Cornell University)|Feb 13, 2026

Adaptive optics and wavefront sensing被引用数 0

ひとこと要約

feasibility study は 1.3 m DFOT で speckle interferometry を sCMOS ディテクタを用いて six binary stars を観測し、追跡誤差とデータ解析の実行可能性を評価する。

ABSTRACT

We present a feasibility study exploring the implementation of optical interferometry and speckle techniques with the 1.3-m Devasthal Fast Optical Telescope (DFOT) at ARIES, which is currently dedicated to photometric observations. Using the sCMOS camera as the DFOT backend, we perform interferometric speckle observations of several binary stars. Standard Speckle Interferometry (SI) algorithms are applied to analyze the recorded data. While this study does not aim to achieve the diffraction limit of DFOT or address a full science-driven resolution case, it serves as a crucial testbed for instrumentation, data acquisition, and analysis of Speckles with DFOT. Notably, we successfully identify and correct tracking-related positional errors in the observed binary systems, demonstrating the viability of the approach. These results provide strong motivation for more systematic observations and future implementation of optical interferometry techniques at meter-class telescopes.

研究の動機と目的

• Assess the feasibility of implementing speckle interferometry with the 1.3 m DFOT at ARIES.
• Evaluate the performance of sCMOS-based speckle observations for binary stars.
• Identify tracking-related positional errors and test corrective analysis methods.
• Provide groundwork for future instrumentation improvements to approach diffraction-limited speckle imaging at meter-class telescopes.

提案手法

• Equip DFOT with a 2048×2048 sCMOS camera as backend for high-speed imaging.
• Record speckle frames in the R-band (~650 nm) with 2 ms exposure and multiple frame sets per target.
• Apply standard Speckle Interferometry data analysis to the recorded frames, including Fourier transform, averaging, and autocorrelation.
• Analyze autocorrelation functions to extract binary signatures and mitigate atmospheric tracking variations.
• Identify limitations due to non-diffraction-limited speckle patterns and propose instrumental improvements.

Figure 1: The Devasthal Fast Optical Telescope (DFOT) along with the sCMOS camera at the backend. The attached computer system is kept at the right, and the dome is closed.

実験結果

リサーチクエスチョン

• RQ1 Can speckle interferometry be effectively implemented on DFOT using an sCMOS detector?
• RQ2 To what extent can speckle autocorrelation mitigate tracking errors for wide binaries observed with a meter-class telescope?
• RQ3 What are the limitations in achieving diffraction-limited speckle patterns with the current setup, and how could instrumentation improvements address them?
• RQ4 What preliminary orbital or binary-signature information can be extracted from available speckle data for the sample targets?

主な発見

Star System	Binary	Orbital Period	Semi-major Axis	Citation Source
A Boötis	Yes	~ 212 days	~ 2.3”	Ren & Fu ( 2013 )
Alpha Ophiuchi	Yes	~ 3,139 days	~ 430”	Gardner et al. ( 2021 )
Gamma Leonis	Yes	~ 553 years	~ 3.09”	Takeda ( 2023 )
Gamma Virginis	Yes	~ 168.93 years	~ 3.639”	Scardia et al. ( 2007 )
Alpha Virginis	Yes	~ 4.01 days	~ 1.71”	Tkachenko et al. ( 2016 )
Zeta Herculis	Yes	~ 34.45 years	~ 1.33”	Söderhjelm ( 1999 )

• Speckle patterns were recorded for six binary stars using a 1.3 m DFOT with an sCMOS backend in the R-band.
• The speckle frames showed blurred patterns indicating the system did not reach diffraction-limited performance.
• Autocorrelation of averaged frames revealed binary signatures in some targets, demonstrating feasibility of the approach for at least wide binaries.
• For wide binaries, orbital signatures could be identified directly in individual frames, while averaging did not yield a static orbit due to atmospheric turbulence.
• Close binaries remained unresolved with the current setup, highlighting the need for instrumental optimization to approach diffraction-limited speckle imaging.
• The results motivate dedicated observations and detector/instrumental enhancements to realize routine intermediate-resolution optical interferometry at meter-class telescopes.

Figure 2: Representative speckle images of six binary systems-A Bootis, $\alpha$ Ophiuchi, $\gamma$ Leonis, $\gamma$ Virginis, $\alpha$ Virginis, and $\zeta$ Herculis-arranged from top left to bottom right. Each frame has an exposure time of 2 ms and has been corrected for instrumental effects throu