TY - GEN

T1 - Measuring the Near-IR Airglow Continuum with Stray Light Reduced Spectrograph

AU - Viuho, Joonas K. M.

AU - Andersen, Michael I.

AU - Fynbo, Johan P. U.

PY - 2022/8/29

Y1 - 2022/8/29

N2 - We present an experimental spectrograph based on a new type of a white pupil echelle spectrograph designed for interline sky continuum measurement. This is an application which requires extremely low instrumental scattered light background and high spectral fidelity due to the faintness of the signal and the fact that the night sky is illuminated by bright hydroxyl emission lines from the red-end of visual spectrum through near infrared wavelengths. The conceptual design is a white pupil echelle spectrograph using a single grating in double pass. The xy-plane of the optical beam is rotated between the two consecutive dispersions thus redirecting the scattered 'grating grass' light from the grating to different direction respective to the spectrum. A mask in the secondary focus prevents this scattered light reaching the camera. The beam rotation is achieved with a normal right-angle prism allowing us to use off-the-shelf optical components and classical geometrical optics to mitigate the issue of hydroxyl airglow emission lines.

AB - We present an experimental spectrograph based on a new type of a white pupil echelle spectrograph designed for interline sky continuum measurement. This is an application which requires extremely low instrumental scattered light background and high spectral fidelity due to the faintness of the signal and the fact that the night sky is illuminated by bright hydroxyl emission lines from the red-end of visual spectrum through near infrared wavelengths. The conceptual design is a white pupil echelle spectrograph using a single grating in double pass. The xy-plane of the optical beam is rotated between the two consecutive dispersions thus redirecting the scattered 'grating grass' light from the grating to different direction respective to the spectrum. A mask in the secondary focus prevents this scattered light reaching the camera. The beam rotation is achieved with a normal right-angle prism allowing us to use off-the-shelf optical components and classical geometrical optics to mitigate the issue of hydroxyl airglow emission lines.

KW - Airglow

KW - airglow continuum

KW - near infrared

KW - spectroscopy

KW - echelle

KW - spectral purity

KW - atmospheric emission

KW - OH SUPPRESSION

U2 - 10.1117/12.2630668

DO - 10.1117/12.2630668

M3 - Conference article

VL - 12184

JO - Progress in Biomedical Optics and Imaging

JF - Progress in Biomedical Optics and Imaging

SN - 1605-7422

M1 - 1218465

T2 - Conference on Ground-Based and Airborne Instrumentation for Astronomy IX

Y2 - 17 July 2022 through 22 July 2022

ER -