Ground-based observatory operations optimized and enhanced by direct atmospheric measurements

McGraw, J. T.; Ackermann, Mark R.; Hines, Dean C.; Hull, Anthony B.; Rossmann, Lisa; Zirzow, D. C.; Brown, Steven W.; Fraser, Gerald T.; Lykke, Keith R.; Smith, A. W.; Stubbs, C. W.; Woodward, John T.

doi:10.1117/12.857787

Cited by 7 publications

(4 citation statements)

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“…Nowadays detector and instrument capabilities probably have the potential to attain even a sub-percent accuracy, but their full exploitation requires techniques for monitoring the actual throughput of the telescopes (Stubbs et al 2007;Regnault et al 2009;Doi et al 2010) and for monitoring the atmospheric layers above the ground-based telescope with a more accurate and complete spatial and temporal sampling than the classical weather stations. This approach, conceptually similar to the adaptive optics (AO) philosophy, should be able to provide photometric measurement corrections for direction-, wavelength-, and time-dependent astronomical extinction, as described in McGraw et al (2010); Zimmer et al (2010Zimmer et al ( , 2016, pursuing the development of what we may call "Adaptive Photometry", something similar to AO, but in the photometric regime. In this way, photometric observations can be corrected in real time, taking into account the actual transmission of the column of air through which calibrations are being made.…”

Section: Discussionmentioning

confidence: 99%

The Gaia spectrophotometric standard stars survey – IV. Results of the absolute photometry campaign

Altavilla

Marinoni

Pancino

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present Johnson-Kron-Cousins BVRI photometry of 228 candidate spectrophotometric standard stars for the external (absolute) flux calibration of Gaia data. The data were gathered as part of a ten-year observing campaign with the goal of building the external grid of flux standards for Gaia and we obtained absolute photometry, relative photometry for constancy monitoring, and spectrophotometry. Preliminary releases of the flux tables were used to calibrate the first two Gaia releases. This paper focuses on the imaging frames observed in good sky conditions (about 9100). The photometry will be used to validate the ground-based flux tables of the Gaia spectrophotometric standard stars and to correct the spectra obtained in non-perfectly photometric observing conditions for small zeropoint variations. The absolute photometry presented here is tied to the Landolt standard stars system to ≃1 per cent or better, depending on the photometric band. Extensive comparisons with various literature sources show an overall ≃1 per cent agreement, which appears to be the current limit in the accuracy of flux calibrations across various samples and techniques in the literature. The Gaia photometric precision is presently of the order of 0.1 per cent or better, thus various ideas for the improvement of photometric calibration accuracy are discussed.

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Section: Discussionmentioning

confidence: 99%

The Gaia spectrophotometric standard stars survey – IV. Results of the absolute photometry campaign

Altavilla

Marinoni

Pancino

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Since they are mounted next to each other, there is a region close to the LIDAR where the backscattered light from the laser does not reach the detector (no overlap), or only part of it is seen (partial overlap). Kunz 1996;McGraw et al 2010), however none goes without previous assumptions about the aerosol extinction-to-backscatter efficiency (LIDAR ratio) throughout the retrieval range.…”

Section: Adapted Signal Inversion Algorithmmentioning

confidence: 99%

Characterizing the aerosol atmosphere above the Observatorio del Roque de los Muchachos by analyzing seven years of data taken with an GaAsP HPD-readout, absolutely calibrated elastic LIDAR

Fruck,

Gaug,

Hahn

et al. 2022

Preprint

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We present a new elastic LIDAR concept, based on a bi-axially mounted Nd:YAG laser and a telescope with HPD readout, combined with fast FADC signal digitization and offline pulse analysis. The LIDAR return signals have been extensively quality checked and absolutely calibrated. We analyze seven years of quasi-continuous LIDAR data taken during those nights when the MAGIC telescopes were operating. Characterization of the nocturnal ground layer yields zenith and azimuth angle dependent aerosol extinction scale heights for clear nights. We derive aerosol transmission statistics for light emitted from various altitudes throughout the year and separated by seasons. We find further seasonal dependencies of cloud base and top altitudes, but none for the LIDAR ratios of clouds. Finally, the night sky background light is characterized using the LIDAR photon backgrounds.

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“…Improving the precision of upcoming ground-based sky surveys will benefit from a careful determination of this atmospheric optical transfer function. 1,2 Photometric calibration issues are currently the dominant source of uncertainty for using type Ia supernovae to determine the properties of the Dark Energy, and this provides a strong motivation for improving the precision of photometric calibration. 3 An approach that breaks the photometric calibration problem into two distinct measurement challenges (the apparatus and the atmosphere) is described in Stubbs & Tonry (2006), 4 and we follow that methodology here.…”

Section: Introductionmentioning

confidence: 99%

Comparison of MODTRAN5 atmospheric extinction predictions with narrowband astronomical flux observations

et al. 2015

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Improving the precision of ground-based astronomical observations is an objective of both current (e.g. PanSTARRS1) and future (e.g. Dark Energy Survey and the Large Synoptic Survey Telescope) sky surveys. An important element of this effort is to determine the optical attenuation imposed by the atmosphere. We have obtained atmospheric extinction observations from narrowband photometry (typically 10 nm bandwidth) at central wavelengths of 380 nm, 488 nm, 500 nm, 585 nm, 656 nm, 675 nm and 840 nm. The passbands were selected to measure the continuum component (predominantly from Rayleigh and aerosol scattering) of atmospheric attenuation, and to avoid molecular absorption features in the atmosphere. We compare these atmospheric extinction observations with predictions from MODTRAN5, a commonly used computer model of atmospheric optical transmission. The MODTRAN5 calculations were informed by a satellite-based determination of atmospheric ozone on the night of observations. We also adjusted the MODTRAN5 predictions of Rayleigh scattering to account for the difference between the default pressure and that measured at the observatory on the night of observations. We find excellent agreement across all passbands between the pressureadjusted MODTRAN5 extinction model and the observations, within our typical extinction uncertainty of 0.013 mag/airmass, but only if we exclude any aerosol scattering component in the MODTRAN5 model. Even though this is a very limited test, with observations of a single star for a single night, the fact that we obtain excellent agreement between extinction measurements and the MODTRAN5 model, with no adjustable fit parameters, bodes well for exploiting MODTRAN5 to increase the precision of ground-based flux measurements.

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Ground-based observatory operations optimized and enhanced by direct atmospheric measurements

Cited by 7 publications

References 0 publications

The Gaia spectrophotometric standard stars survey – IV. Results of the absolute photometry campaign

The Gaia spectrophotometric standard stars survey – IV. Results of the absolute photometry campaign

Characterizing the aerosol atmosphere above the Observatorio del Roque de los Muchachos by analyzing seven years of data taken with an GaAsP HPD-readout, absolutely calibrated elastic LIDAR

Comparison of MODTRAN5 atmospheric extinction predictions with narrowband astronomical flux observations

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