Study of aerosol content based on spectrophotometric observations: A comparison with long-term extinction profile from photometric observations

Malasan, Hakim L.; Prabowo, D. A.; Adhyaqsa, A.; Rabbani, M. Rafif; Puspitarini, L.; Aprilia,

doi:10.1088/1755-1315/537/1/012008

Cited by 4 publications

(2 citation statements)

References 4 publications

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“…Here 𝑀 𝑧,band is the apparent magnitude measured inside atmosphere, 𝑀 0,band is the extra-atmospheric magnitude, and 𝐾 band is atmospheric extinction coefficient. 𝐹 (𝑧) is airmass which is adopted as follows [32]:…”

Section: Atmospheric Extinction Coefficientmentioning

confidence: 99%

Characterisations of the HinOTORI telescope with a three-color imager at Ali Observatory in Western Tibet

et al. 2022

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HinOTORI is a new telescope supported by an international collaboration project between China and Japan. It is a 50 centimeter telescope equipped with simultaneous three-color imagers (u', R C, and I C bands). It is located at Ali Observatory at an altitude of 5100m. Thanks to the high altitude and extreme dryness, Ali site is one of the most suitable sites for optical astrometry. HinOTORI telescope aims at detecting optical transients such as the counterparts of gravitational wave (GW) sources, supernovae, gamma-ray bursts (GRB) and so on. This paper describes the site information, design of simultaneous three-color optical layout, system instruments and whole control system. We also report some telescope characterisations for three bands (u'/R C/I C) respectively, such as Hartmann constant (0.49”/0.56”/0.60”), best focus position (3.922/3.920/3.903 mm), PSF FWHM size (3.755/3.328/3.167pixels), total transmittance and limiting magnitude (15.69/17.57/17.05mag, 10 σ 30 seconds exposure time). With different airmass observation data, the atmospheric extinction coefficients of three bands (0.366/0.061/0.026) were also derived.

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Section: Atmospheric Extinction Coefficientmentioning

confidence: 99%

Characterisations of the HinOTORI telescope with a three-color imager at Ali Observatory in Western Tibet

et al. 2022

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“…Based on the moonlit sky brightness modelling,Yao et al (2013) derived 𝑘 = 0.23 for Xinglong Station China. At Bosscha Observatory,Malasan et al (2020) reported the extinction coefficient between 0.30 and 0.88 based on the spectroscopic observation (4200 − 7000 Å) in 2019. That quoted value is more than double the coefficient derived for the same site in 1993.…”

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confidence: 99%

Characterisation of Timau National Observatory using limited in-situ measurements

Priyatikanto,

Mumpuni,

Hidayat

et al. 2022

Preprint

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A new astronomical observatory in southeastern Indonesia is currently under construction. This Timau National Observatory will host a 3.8-metre telescope for optical and near-infrared observations. To support the operation and planning, the characterisation of the site needs to be appropriately performed. However, limited resources and access to the site hindered the deployment of instruments for comprehensive site testing. Fortunately, in-situ sky brightness data from the Sky Quality Meter (SQM) have been available for almost two years. Based on the data acquired in 470 nights, we obtain a background sky brightness of 𝜇 0 = 21.86 ± 0.38 magnitude/arcsec 2 . Additionally, we evaluate the moonlit sky brightness to estimate the atmospheric extinction coefficient (𝑘) and level of scattering on site. We find an alleviated value of 𝑘 = 0.48 ± 0.04, associated with a high atmospheric aerosol content. It is considered regular for an equatorial area situated at a low altitude (∼1300 masl). By analysing the fluctuation of the sky brightness and infrared images from Himawari-8 satellite, we estimate the available observing time (AOT) of at least 5.3 hours/night and the yearly average percentage of usable nights of 66%. The monthly average AOT from SQM and satellite data analysis correlate with 𝑅 = 0.82. In terms of the monthly percentage of usable nights, the correlation coefficient is 𝑅 = 0.78. During the wet season (November-April), the results from SQM and satellite data analysis deviate more significantly, mainly due to the limited capability of Himawari-8 in detecting fragmented low-altitude clouds. According to these results, we expect Timau to complement other observatories greatly.

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Spectroscopic Observations of Ten Galactic Wolf–Rayet Stars at Bosscha Observatory: Determination of Stellar Parameters and Mass-loss Rates

Malasan,

Setyo Budi

2024

Res. Astron. Astrophys.

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We present optical spectra of 10 galactic Wolf-Rayet (WR) stars that consist of 5 WN and 5 WC stars. The optical observation was conducted using a low-resolution spectrograph NEO-R1000 (λ/Δλ ∼1000) at GAO-ITB RTS (27.94 cm, F/10.0), Bosscha Observatory, Lembang. We implemented stellar atmosphere Postdam Wolf-Rayet (PoWR) grid modeling to derive stellar parameters. The normalized optical spectrum can be used to find the best model from the available PoWR grid, then we could derive stellar temperature and transformation radius. To derive luminosity, stellar radius and color excess, we conducted a Spectral Energy Distribution (SED) analysis with additional data on the near-ultraviolet spectrum from The International Ultraviolet Explorer (IUE) database, UBV and 2-MASSJHK broadband filter data. Additional analysis to derive asymptotic terminal wind velocity was conducted from the P-Cygni profile analysis of the high-resolution IUE UV spectrum. With previously derived parameters, we could determine the mass loss rate of theWolf-Rayet stars. Furthermore, we compared our results with previous work that used PoWR code and the differences are not more than 20%. We conclude that the PoWR spectral grid is sufficient to derive WR stellar parameters quickly and could provide more accurate initial parameter input to the PoWR program code.

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Study of aerosol content based on spectrophotometric observations: A comparison with long-term extinction profile from photometric observations

Cited by 4 publications

References 4 publications

Characterisations of the HinOTORI telescope with a three-color imager at Ali Observatory in Western Tibet

Characterisations of the HinOTORI telescope with a three-color imager at Ali Observatory in Western Tibet

Characterisation of Timau National Observatory using limited in-situ measurements

Spectroscopic Observations of Ten Galactic Wolf–Rayet Stars at Bosscha Observatory: Determination of Stellar Parameters and Mass-loss Rates

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