Stray light design and analysis of the SNAP Telescope

Sholl, Michael; Grochocki, Frank; Fleming, John C.; Besuner, Robert; Jelinsky, Patrick; Lampton, M.

doi:10.1117/12.732517

Cited by 12 publications

(3 citation statements)

References 0 publications

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“…[5][6][7][8] . 미광은 일반적으로 경통 내부에서 부분 반사 및 전반사에 의해 생기는 유령광(ghost light) 과 렌즈 면 및 경통 내부의 산란에서 생기는 산란광(scattering light)으로 나눌 수 있다 [5] .…”

Section: Fig 3 Comis Cross-sectional Viewunclassified

Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Lee¹,

Lee²

2012

Korean Journal of Optics and Photonics

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This paper reports on the stray light analysis results of a compact imaging spectrometer (COMIS) for a microsatellite STSAT-3. COMIS images Earth's surface and atmosphere with ground sampling distances of 27 m at the 18 ~ 62 spectral bands (0.4 ~ 1.05 μm) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. The telescope images a 27 m × 28 km area of Earth surface onto a slit of dimensions 11.8 μm × 12.1 mm. This corresponds to a ground sampling distance of 27 m and a swath width of 28 km for nadir looking posture at an altitude of 700 km. Then the optics relays and disperses the slit image onto the detector thereby producing a monochrome image of the entrance slit formed on each row of detector elements. The spectrum of each point in the row is imaged along a detector column. The optical mounts and housing structures are designed in order to prevent stray light from arriving onto the image and so deteriorating the signal to noise ratio (SNR). The stray light analysis, performed by a non-sequential ray tracing software (LightTools) with three dimensional housing and lens modeling, confirms that the ghost and stray light arriving at the detector plane has the relative intensity of ~10 -5 and furthermore it locates outside the concerned image size i.e. the field of view of the optics.

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Section: Fig 3 Comis Cross-sectional Viewunclassified

Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Lee¹,

Lee²

2012

Korean Journal of Optics and Photonics

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“…The necessity of mitigating stray light in telescopes and other astronomical instruments is well known, and a variety of techniques have been developed to analyze stray-light problems and design solutions. Previous studies of these methods include recent ones by Brendel, 1 who examined the problem of lunar stray light on a balloon-born UV-telescope, Clermont, 2 who examined stray-light suppression in a ground-based telescope design, Grochocki, 3 who studied the stray light performance of the Operational Land Imager Landsat 8 instrument and Sholl 4 who studied the requirements of the SNAP proposed to study dark matter, and older ones such as Stauder. 5 Complex software programs have been developed that take advantage of improvements in computer performance, such as FRED or Zemax OpticStudio.…”

Section: Introductionmentioning

confidence: 99%

Scattering properties of black pigments: implications for detecting faint sources near the moon using ground-based telescopes

Mayer,

Jeong,

Brendel

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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The search for artificial and natural objects in both cis-lunar and trans-lunar space has grown increasingly important. To accurately detect and track small objects, stray light mitigation is a necessity. Observations conducted in 2022 from a ground-based telescope intended to track such objects have been hampered by excess lunar stray light. In this paper, we present work done to resolve this problem by applying black pigments to the optical tube and thus suppressing its surface scattering. A non-sequential ray tracing model was created to analyze the telescope’s final focal plane irradiance. This model was used to identify critical and illuminated surfaces to determine the stray light paths that have affected observations. We conducted experimental tests to measure the Bidirectional Reflectance Distribution Function (BRDF) of various practical, readily available, and robust black coatings, including paints such as Black 3.0 and Musou. After application on the actual telescope tube, the new surface coating reduced the photon count on the detector from a variable-angle off-axis point source by 76% over all angles measured.

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“…Different evaluation methods are related to the characteristics of the instrument and the means of stray light suppression. Sholl et al [22] analyzed the stray light situation of an SNAP telescope. The stray light was suppressed by means such as an outer baffle and vanes, and the model was established and analyzed using ASAP software.…”

Section: Introductionmentioning

confidence: 99%

Stray Light Analysis and Elimination of an Optical System Based on the Structural Optimization Design of an Airborne Camera

Yang

Qü

et al. 2022

Applied Sciences

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An aspherical airborne camera has excellent performance in the field of photoelectric reconnaissance equipment. However, the image plane contrast of the optical system will be reduced by stray light originating from inside or outside of the optical system. In the present work, the self-designed aspheric airborne camera is manufactured with a baffle and vanes to reduce the impact of stray light on the camera imaging quality. TracePro software is used to analyze the stray light and establish an ABg mathematical model based on the scattering intensity measurement. The incident angle of the light parallel to the optical axis is set, and ray tracing is performed on the optical machine model to verify whether it conforms to the optical system design. The results showed that when the incident angle of the light source is greater than 0.5°, the point source transmittance (PST) value drops rapidly, and when the incident angle is 30°, the PST value of the system is in the order of 10−8. Stray light analysis verifies that the self-designed aspheric surface-based camera optomechanical structure has the ability to suppress stray light. The design of the baffle and vanes further enhances the ability of the optical system to suppress stray light, which can provide a reference for the design of a stray light elimination structure.

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Stray light design and analysis of the SNAP Telescope

Cited by 12 publications

References 0 publications

Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3

Scattering properties of black pigments: implications for detecting faint sources near the moon using ground-based telescopes

Stray Light Analysis and Elimination of an Optical System Based on the Structural Optimization Design of an Airborne Camera

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