Spherical Astronomy

Karttunen, Hannu; Kröger, Pekka; Oja, Heikki; Poutanen, Markku; Donner, Karl Johan

doi:10.1007/978-1-4612-3160-8_2

Cited by 7 publications

(7 citation statements)

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“…11 12 The use of the sun, moon, and scattered sky light, together with fixed light sources, permit measurements of both the tropospheric and stratospheric concentrations of many species, 13 -16 but this option is not demonstrated here.…”

Section: B Measurement Routinesmentioning

confidence: 98%

Differential optical absorption spectroscopy (DOAS) system for urban atmospheric pollution monitoring

et al. 1993

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We describe a fully computer-controlled differential optical absorption spectroscopy system for atmospheric air pollution monitoring. A receiving optical telescope can sequentially tune in to light beams from a number of distant high-pressure Xe lamp light sources to cover the area of a medium-sized city. A beam-finding servosystem and automatic gain control permit unattended long-time monitoring. Using an astronomical code, we can also search and track celestial sources. Selected wavelength regions are rapidly and repetitively swept by a monochromator to sensitively record the atmospheric absorption spectrum while avoiding the detrimental effects of atmospheric turbulence. By computer fitting to stored laboratory spectra, we can evaluate the path-averaged concentration of a number of important pollutants such as NO 2 , SO 2 , and 03. A measurement of NH 3 and NO close to the UV limit is also demonstrated.

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Section: B Measurement Routinesmentioning

confidence: 98%

Differential optical absorption spectroscopy (DOAS) system for urban atmospheric pollution monitoring

et al. 1993

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“…Equation (6) was obtained from Eq. (7.45) of Karttunen et al (2007). Here, the geocentric distance ∆ = 1 au is expressed in kilometers, S is the projected area of Phaethon measured in square kilometers, and H and H Sun stand for the absolute magnitude of Phaethon and the apparent magnitude of the Sun at a distance of r = 1 au, correspondingly.…”

Section: Umov Effect Applied To Phaethonmentioning

confidence: 99%

Umov effect in asteroid (3200) Phaethon

Zheltobryukhov

Chornaya

Kochergin

et al. 2018

A&A

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Context. The near-Earth asteroid (3200) Phaethon occasionally reveals a comet-like activity. It is a parent body to the Geminid meteor shower and considered as a target for the space mission called Demonstration and Experiment of Space Technology for Interplanetary Voyage Phaethon Flyby Dust Science, DESTINY + . Aims. We aim to characterize Phaethon through measurements of the degree of linear polarization P measured on Phaethon at large phase angles on its closest approach to Earth on December 17, 2017. These observations allow a more accurate estimation of the maximum value of the degree of linear polarization P max of Phaethon, and therefore, of studying the Umov effect. Methods. We performed polarimetric measurements of Phaethon at large phase angles α and thus constrained its P max . We also estimated the geometric albedo a based on the data available in the literature. The obtained P max and A were analysed with the Umov effect previously derived for the Moon that establishes an inverse linear correlation between log(P max ) and log(A) in the lunar regolith. Results. Our polarimetric observations of Phaethon in the visible reveal the degree of linear polarization P ≈ (17.23 ± 2.00)% at α ≈ 57.9 • and P ≈ (31.86 ± 2.00)% at α ≈ 73.2 • , which demonstrates no significant wavelength dependence within the error bars of our measurements (±2%). These data, when combined with what has previously been reported in the literature, suggests at least three types of polarimetric response on Phaethon. For two of them, we infer the maximum linear polarization to be P max ≈ 57.9%, occurring at α max = 131 • and P max ≈ 44.5% occurring at α max = 127 • . We estimate the geometric albedo (adjusted to α = 3 • ) to be A R = 0.075 ± 0.007 in the R filter, which appears to be consistent with dark F-type asteroids, as which Phaethon was first classified. We examine the Umov diagrams previously inferred for lunar regolith and find that they are hardly applicable to Phaethon and therefore not to other asteroids either.

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“…This opposition effect is dependent upon the physical properties of the body. 57 Therefore, pðαÞ has been calculated from E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 2 ; 3 2 6 ; 6 5 3…”

Section: Target Availabilitymentioning

confidence: 99%

Small bodies science with the Twinkle space telescope

Edwards¹,

Lindsay²,

Savini³

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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Twinkle is an upcoming 0.45-m space-based telescope equipped with a visible and two near-infrared spectrometers covering the spectral range 0.4 to 4.5 μm with a resolving power R ∼ 250 (λ < 2.42 μm) and R ∼ 60 (λ > 2.42 μm). We explore Twinkle's capabilities for small bodies science and find that, given Twinkle's sensitivity, pointing stability, and spectral range, the mission can observe a large number of small bodies. The sensitivity of Twinkle is calculated and compared to the flux from an object of a given visible magnitude. The number, and brightness, of asteroids and comets that enter Twinkle's field of regard is studied over three time periods of up to a decade. We find that, over a decade, several thousand asteroids enter Twinkle's field of regard with a brightness and nonsidereal rate that will allow Twinkle to characterize them at the instrumentation's native resolution with SNR > 100. Hundreds of comets can also be observed. Therefore, Twinkle offers researchers the opportunity to contribute significantly to the field of Solar System small bodies research.

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Spherical Astronomy

Cited by 7 publications

References 0 publications

Differential optical absorption spectroscopy (DOAS) system for urban atmospheric pollution monitoring

Differential optical absorption spectroscopy (DOAS) system for urban atmospheric pollution monitoring

Umov effect in asteroid (3200) Phaethon

Small bodies science with the Twinkle space telescope

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