Astroclimate parameters of the Kyiv observatories
Astroclimate parameters such as the atmospheric extinction, the night-sky brightness, and the seeing are studied using the observational data obtained at some Kyiv observatories. The first parameter is determined using the brief Bouguer method. The night-sky brightness is calculated using the images...
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Rieznik, K. Reshetnyk, V.M. 2017-06-06T18:35:46Z 2017-06-06T18:35:46Z 2012 Astroclimate parameters of the Kyiv observatories / K. Rieznik, V.M. Reshetnyk // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 203-205. — Бібліогр.: 3 назв. — англ. 2227-1481 https://nasplib.isofts.kiev.ua/handle/123456789/119407 Astroclimate parameters such as the atmospheric extinction, the night-sky brightness, and the seeing are studied using the observational data obtained at some Kyiv observatories. The first parameter is determined using the brief Bouguer method. The night-sky brightness is calculated using the images of standard stars in different filters. And the seeing is estimated basing on the FWHM of star profiles obtained during a set of observations at Kyiv observatories. We would like to thank Simon A. O. for the granted observational data. en Головна астрономічна обсерваторія НАН України Advances in Astronomy and Space Physics Astroclimate parameters of the Kyiv observatories Article published earlier |
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Astroclimate parameters of the Kyiv observatories |
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Astroclimate parameters of the Kyiv observatories Rieznik, K. Reshetnyk, V.M. |
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Astroclimate parameters of the Kyiv observatories |
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Astroclimate parameters of the Kyiv observatories |
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Astroclimate parameters of the Kyiv observatories |
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astroclimate parameters of the kyiv observatories |
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Rieznik, K. Reshetnyk, V.M. |
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Rieznik, K. Reshetnyk, V.M. |
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2012 |
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Advances in Astronomy and Space Physics |
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Головна астрономічна обсерваторія НАН України |
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Astroclimate parameters such as the atmospheric extinction, the night-sky brightness, and the seeing are studied using the observational data obtained at some Kyiv observatories. The first parameter is determined using the brief Bouguer method. The night-sky brightness is calculated using the images of standard stars in different filters. And the seeing is estimated basing on the FWHM of star profiles obtained during a set of observations at Kyiv observatories.
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Astroclimate parameters of the Kyiv observatories / K. Rieznik, V.M. Reshetnyk // Advances in Astronomy and Space Physics. — 2012. — Т. 2., вип. 2. — С. 203-205. — Бібліогр.: 3 назв. — англ. |
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AT rieznikk astroclimateparametersofthekyivobservatories AT reshetnykvm astroclimateparametersofthekyivobservatories |
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2025-11-26T01:42:46Z |
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Astroclimate parameters of the Kyiv observatories
K.Rieznik∗, V.M.Reshetnyk
Advances in Astronomy and Space Physics, 2, 203-205 (2012)
© K.Rieznik, V.M.Reshetnyk, 2012
Taras Shevchenko National University of Kyiv, Glushkova ave., 4, 03127, Kyiv, Ukraine
Astroclimate parameters such as the atmospheric extinction, the night-sky brightness, and the seeing are stud-
ied using the observational data obtained at some Kyiv observatories. The �rst parameter is determined using the
brief Bouguer method. The night-sky brightness is calculated using the images of standard stars in di�erent �lters.
And the seeing is estimated basing on the FWHM of star pro�les obtained during a set of observations at Kyiv
observatories.
Key words: atmospheric e�ects, light pollution.
introduction
Ground-based astronomical observations are car-
ried out through the entire atmosphere which is con-
tinuously moving and changing, that results in addi-
tional obstacles in obtaining high-quality data. The
whole set of atmospheric conditions that a�ect as-
tronomical measurements is called astroclimate. As-
tronomical observations conducted from the Earth
surface require a number of clear nights, high atmo-
sphere transparency and dark sky. The presence of
some active astronomical observatories in Kyiv re-
quires a constant monitoring of astroclimate param-
eters. Such activities are carried out in the majority
of observatories [1, 2, 3].
data and data processing
To determine the extinction coe�cient the data
received in 2012 by A. Simon and V.Reshetnyk at
Lisnyky observational station of the Astronomical
Observatory of the Kyiv National Taras Shevchenko
University at AZT-8 telescope were used. Images
taken in 2009 by V.Reshetnyk with the Celestron
CGE-1400 telescope at the Main Astronomical Ob-
servatory of the National Academy of Sciences of
Ukraine (MAO NASU) were used for estimation of
the night-sky background brightness and seeing val-
ues.
All the images were corrected for dark, �at �eld
and bias. The special software was developed for fast
image processing of the large data arrays. Its relia-
bility was tested in comparison with the results of
MaxIm DL and IDL DAOPHOT.
atmospheric extinction
We used the following formula of the brief
Bouguer method to calculate the value of the atmo-
spheric extinction:
α(λ) =
[mA(λ)−mB(λ)]− [m0
A(λ)−m0
B(λ)]
[M(zA)−M(zB)]
, (1)
where α(λ) is the extinction coe�cient, mA(λ) and
mB(λ) are the observed magnitudes, m0
A(λ) and
m0
B(λ) are the magnitudes from a catalogue, M(zA)
and M(zB) are airmasses.
Photometric data were obtained for the stars
listed in Table 1. These stars are not photometric
standards. Extinction coe�cients were calculated for
di�erent �lters. Results are given in Table 2.
Table 1: The list of observed stars.
TYC423 1203 1 TYC423 929 1
USNO-A2.0 0900-10345260 TYC3507 2315 1
USNO-A2.0 1350-09083719 TYC3507 2315 1
USNO-A2.0 1350-10099071 TYC3553 232 1
USNO-A2.0 0675-21954842 TYC6253 3197 1
USNO-A2.0 0675-21937274 TYC3553 114 1
For one series of frames we calculated the extinc-
tion coe�cients using di�erent pairs of stars. Their
errors were calculated as a standard deviation.
Table 2: Extintion coe�cients.
Filter α ∆
B 0.55 0.05
V 0.35 0.10
R 0.42 0.32
I 0.36 0.07
∗plazma313@gmail.com
203
Advances in Astronomy and Space Physics K.Rieznik, V.M.Reshetnyk
night-sky brightness
The identi�cation of stars and the determination
of scales were conducted using the calibrated images.
Standard photometric stars in proper colour bands
were found, using the VizieR Catalogue Service1.
The instrumental magnitude of the stars and the sky
background were obtained using the own developed
software. The brightness of the sky was calculated
using the Pogson formula:
mstar −msky = −2.5 lg
Bstar
Bsky
, (2)
where mstar and msky are the star and night-sky
background magnitudes, Bstar and Bsky are the star
and night-sky brightnesses.
Using catalogues available via the VizieR Cata-
logue Service, we found apparent magnitudes of the
identi�ed stars in the U, B, V, R, I bands. Ex-
tinction was estimated using the following relation:
m(λ)−m0(λ) = α(λ)M(z). Extra-atmospheric mag-
nitudes were taken from catalogues. Zenith distance
was found for the series of frames in assumption that
the temporal changes in results of observations are
negligible and changes in the angle can be neglected.
The values of the night-sky background, msky, in
mag arcsec−2 and their errors are given in Table 3.
Errors of U-magnitudes could not be estimated be-
cause of the lack of reliable data. Errors were ob-
tained using the following relation:
∆msky =
√(
2.5
∆Bstar
Bstar ln 10
)2
+
(
2.5
∆Bsky
Bsky ln 10
)2
.
Table 3: Night-sky background brightness.
U B V R I
msky 18.2 18.86 18.10 17.94 17.69
∆msky � 0.08 0.02 0.01 0.76
seeing
The seeing was estimated quantitatively from the
analysis of the averaged star pro�le using the FWHM
in the IDL image processing procedures. 2D and 3D
averaged pro�les of stars were built in 10×10 pixel
areas around the central stars extracted from the
original images (Fig. 1).
Then the star pro�les were �tted using the Gaus-
sian function with the following formula:
F (x, y) = A0 +A1e
−U/2, (3)
where U = (x/a)2 + (y/b)2. Here x and y are hori-
zontal and vertical dimensions (conventionally). The
results for FWHM and their errors are given in Ta-
ble 4. Errors were calculated as standard deviations.
Fig. 1: Three-dimensional star pro�le. Dimensions of
stars are given along the both horizontal axes and the
relative �ux is given along the vertical one.
Table 4: Value of FWHM parameter.
Time (JD) FWHM ∆FWHM
2454838.2556 3.63 0.75
2454843.2261 4.44 0.85
2454843.2524 3.5 1.3
2454885.2896 3.34 0.14
2454885.3171 2.76 0.06
2454885.3297 3.26 0.04
2454885.3931 3.01 0.08
2454885.4200 3.0 1.7
2454885.4347 2.44 0.15
2455408.3053 2.79 0.15
2455408.4178 2.91 0.25
2455415.3056 2.76 0.81
Fig. 2: FWHM parameter changes for the series of im-
ages.
FWHM change graph which is an intermediate
result for series of frames obtained on 01.06.2009 is
1http://vizier.u-strasbg.fr/viz-bin/VizieR
204
Advances in Astronomy and Space Physics K.Rieznik, V.M.Reshetnyk
shown in Fig. 2. Here the bold line is the curve of the
temperature changes. The correlation coe�cient is
0.94, that can be explained by telescope defocusing
caused by ambient temperature changes.
results and conclusions
The estimations of the extinction coe�cient were
obtained using the brief Bouguer method. The ob-
tained results for observational night were conformed
with the values for middle latitudes observatories.
The value of the night-sky brightness indicates a sig-
ni�cant illumination from the Kyiv city. The ob-
tained seeing cannot compete with seeing from high-
land observatories but its values are good enough to
to meet the requirements of the scienti�c studies.
acknowledgement
We would like to thank SimonA.O. for the
granted observational data.
references
[1] AndrukV.N. 1996, Kinematika i Fizika Nebesnykh Tel,
12, 4, 60
[2] BennC.R. & Ellison S. L. 1998, New Astronomy Reviews,
42, 503
[3] Vernin J. & Munoz-TunonC. 1994, A&A, 284, 311
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