Results of joint project on linking optical-radio reference frames
Results of international co-operation between observatories from China, Russia, Turkey, and Ukraine on refinement of linking optical and radio reference frames are discussed. About 300 fields around extragalactic radio sources in the selected fields of extragalactic radio sources from −40 to +70 deg...
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| Cite this: | Results of joint project on linking optical-radio reference frames / Z. Aslan, R. Gumerov, W. Jin, I. Khamitov, N. Maigurova, G. Pinigin, Yu. Protsyuk, A. Shulga, Z. Tang, S. Wang // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 333-337. — Бібліогр.: 15 назв. — англ. |
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Aslan, Z. Gumerov, R. Jin, W. Khamitov, I. Maigurova, N. Pinigin, G. Protsyuk, Yu. Shulga, A. Tang, Z. Wang, S. 2015-04-03T18:23:10Z 2015-04-03T18:23:10Z 2005 Results of joint project on linking optical-radio reference frames / Z. Aslan, R. Gumerov, W. Jin, I. Khamitov, N. Maigurova, G. Pinigin, Yu. Protsyuk, A. Shulga, Z. Tang, S. Wang // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 333-337. — Бібліогр.: 15 назв. — англ. 0233-7665 https://nasplib.isofts.kiev.ua/handle/123456789/79669 Results of international co-operation between observatories from China, Russia, Turkey, and Ukraine on refinement of linking optical and radio reference frames are discussed. About 300 fields around extragalactic radio sources in the selected fields of extragalactic radio sources from −40 to +70 degrees in declination were observed with CCD ground-based telescopes. The catalogue of optical positions of more than 200 ERS with average accuracy 30 mas in ICRF by using of secondary reference stars from the UCAC2 and USNO-B1.0 catalogues was obtained as a result of this cooperation. The intermediate internal estimation of link between optical and radio reference frames was shown the angle values near zero within an accuracy of about 6 mas by using of secondary reference stars from UCAC2. A comparison of presented results with those of other investigations was made. Authors thanks are expressed to Norbert Zacharis and the UCAC team at USNO for effective placing at our disposal new UCAC2 catalogue. This research has been partly supported by the Russian Foundation of Basic Research (Grant No. 02-02-17076a). en Головна астрономічна обсерваторія НАН України Кинематика и физика небесных тел MS4: Positional Astronomy and Global Geodynamics Results of joint project on linking optical-radio reference frames Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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Results of joint project on linking optical-radio reference frames |
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Results of joint project on linking optical-radio reference frames Aslan, Z. Gumerov, R. Jin, W. Khamitov, I. Maigurova, N. Pinigin, G. Protsyuk, Yu. Shulga, A. Tang, Z. Wang, S. MS4: Positional Astronomy and Global Geodynamics |
| title_short |
Results of joint project on linking optical-radio reference frames |
| title_full |
Results of joint project on linking optical-radio reference frames |
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Results of joint project on linking optical-radio reference frames |
| title_full_unstemmed |
Results of joint project on linking optical-radio reference frames |
| title_sort |
results of joint project on linking optical-radio reference frames |
| author |
Aslan, Z. Gumerov, R. Jin, W. Khamitov, I. Maigurova, N. Pinigin, G. Protsyuk, Yu. Shulga, A. Tang, Z. Wang, S. |
| author_facet |
Aslan, Z. Gumerov, R. Jin, W. Khamitov, I. Maigurova, N. Pinigin, G. Protsyuk, Yu. Shulga, A. Tang, Z. Wang, S. |
| topic |
MS4: Positional Astronomy and Global Geodynamics |
| topic_facet |
MS4: Positional Astronomy and Global Geodynamics |
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2005 |
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English |
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Кинематика и физика небесных тел |
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Головна астрономічна обсерваторія НАН України |
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Article |
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Results of international co-operation between observatories from China, Russia, Turkey, and Ukraine on refinement of linking optical and radio reference frames are discussed. About 300 fields around extragalactic radio sources in the selected fields of extragalactic radio sources from −40 to +70 degrees in declination were observed with CCD ground-based telescopes. The catalogue of optical positions of more than 200 ERS with average accuracy 30 mas in ICRF by using of secondary reference stars from the UCAC2 and USNO-B1.0 catalogues was obtained as a result of this cooperation. The intermediate internal estimation of link between optical and radio reference frames was shown the angle values near zero within an accuracy of about 6 mas by using of secondary reference stars from UCAC2. A comparison of presented results with those of other investigations was made.
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0233-7665 |
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https://nasplib.isofts.kiev.ua/handle/123456789/79669 |
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Results of joint project on linking optical-radio reference frames / Z. Aslan, R. Gumerov, W. Jin, I. Khamitov, N. Maigurova, G. Pinigin, Yu. Protsyuk, A. Shulga, Z. Tang, S. Wang // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 333-337. — Бібліогр.: 15 назв. — англ. |
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2025-11-25T21:33:42Z |
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| fulltext |
RESULTS OF JOINT PROJECT ON LINKING
OPTICAL–RADIO REFERENCE FRAMES
Z. Aslan3, R. Gumerov2, W. Jin4, I. Khamitov3, N. Maigurova1,
G. Pinigin1, Yu. Protsyuk1, A. Shulga1, Z. Tang4, S. Wang4
1Research Institute “Nikolaev Astronomical Observatory”, MES of Ukraine
1 Observatorna Str., 54030 Mykolaiv, Ukraine
e-mail: pinigin@mao.nikolaev.ua
2Kazan State University
18 Kremlevskaya Str., 420008 Kazan, Russia
e-mail: Rustem.Gumerov@ksu.ru
3Turkish National Observatory TUG
Antalya, 07058 Turkey
e-mail: aslan@tug.tug.tubitak.gov.tr
4Shanghai Astronomical Observatory
80 Nandan Road, 200030 Shanghai, China
e-mail: jwj@center.shao.ac.cn
Results of international co-operation between observatories from China, Russia, Turkey, and
Ukraine on refinement of linking optical and radio reference frames are discussed. About 300 fields
around extragalactic radio sources in the selected fields of extragalactic radio sources from −40
to +70 degrees in declination were observed with CCD ground-based telescopes. The catalogue
of optical positions of more than 200 ERS with average accuracy 30 mas in ICRF by using of
secondary reference stars from the UCAC2 and USNO-B1.0 catalogues was obtained as a result
of this cooperation. The intermediate internal estimation of link between optical and radio refe-
rence frames was shown the angle values near zero within an accuracy of about 6 mas by using
of secondary reference stars from UCAC2. A comparison of presented results with those of other
investigations was made.
INTRODUCTION
The link between optical (Hipparcos) and radio (ICRF) reference frames was realized in position within ±0.6 mas
at the mean epoch 1991.25 and in rotation within ±0.25 mas per year [4]. However, the accuracy of Hipparcos–
ICRF link degrades over time owing to error in the HC proper motion determination. It is a reason for
verification and refinement of frame’s link by different methods and telescopes [9, 15].
The task of the Joint Project (JP) between astronomical observatories from China, Turkey, Russia and
Ukraine is the refinement of optical / radio linking with collaborated CCD telescopes [7, 13].
PROGRAM AND INSTRUMENTATION
The final co-operative program list includes about 300 ERS in the selected fields of celestial sphere in declination
zone from −40◦ to +75◦ and magnitude range from 12m to 20m.
Several CCD telescopes of collaborated observatories which were taken part in the Joint Project are shown
in Table l.
OBSERVATIONS AND REDUCTION
Observations
Up to day positions of 300 ERS optical counterparts were obtained by CCD direct imaging mainly on the 1.0-m
Yunnan and RTT150 telescopes, with secondary reference stars mainly 14–18 magnitudes. More than 2000
CCD frames were obtained during 2000–2003. Every ERS field was observed on average 5–6 times.
c© Z. Aslan, R. Gumerov, W. Jin, I. Khamitov, N. Maigurova, G. Pinigin, Yu. Protsyuk, A. Shulga, Z. Tang, S. Wang, 2004
333
Figure 1. Distribution of the ERS in right ascension and declination
Table 1. Collaborated telescopes
Telescope RTT150, Antalya, TUG (Turkey) 1.0-m Yunnan AO (China) MCT, Nikolaev AO (Ukraine)
ϕ +36◦ +31◦ +47◦
Type Reflector Reflector Refractor
D (mm) / F (mm) 1500 / 11700 1000 / 13000 160 / 2044
CCD ST-8 Andor DW436 TI ISD017A
Size, pixel 1530 × 1020 2K × 2K 1024 × 1024 1040 × 1160
Pixels, mkm 18 × 18 13.5 × 13.5 24 × 24 16 × 16
arcsec/pixel 0.16′′ 0.24′′ 0.37′′ 1.6′′
FOV 4′ × 3′ 8′ × 8′ 6.5′ × 6.5′ 28′ × 31′
Mode Stare Stare, Drift scan Stare Stare, Drift scan
Magnitude 19m ÷ 21m 19m ÷ 23m 17m ÷ 19m 12m ÷ 14m
N1 131 55 116 10
N2 21 41 82 2
Period of observations 2000–2002 2003 2000–2003 2000–2003
Reduction methods and results
Processing of the CCD images including dark, flat, and defect fields corrections, digital image filtration, identi-
fication of objects and determination of coordinates for star-like objects’ in CCD were made using the PUMA
astrometric package [8]. The measured (x, y) centers of images was derived using two-dimensional spherically
symmetric Gaussian fit model.
The linear 6-parameter plate model has been adopted for reduction of measured CCD coordinates (x, y) to
tangential (standard) coordinates (ξ, η)
ξ = c + a · x + b · y,
η = f + d · x + e · y.
The primary optical reference stars from HC are too bright and sparsely distributed in the sky. On the reason
of a small field size of CCD frames of collaborated telescopes (see Table 1) the first processing approach was
made using the USNO-A2.0 and USNO-B1.0 catalogues [5, 6].
Secondary reference stars from USNO have similar magnitudes (16m–18m) in comparison with selected ERS
optical counterparts (Fig. 2). So, correction of brightness equation in ΔαO−R, ΔδO−R are expected negligible.
Differences ΔαO−R · cos δ = αO − αR and ΔδO−R = δO − δR were calculated from ERS optical and radio
coordinates, respectively, and their distributions are shown in Fig. 3a. It is to be noted that some differences in
334
Figure 2. Distribution of secondary reference stars from USNO-B1.0 (dark) and selected ERS (light) with magnitudes
a) the USNO-B1.0 catalogue b) the UCAC2 catalogue
Figure 3. Distribution of differences between ERS coordinates in optical and radio range ΔαO−R · cos δ (light) and
ΔδO−R (dark)
the positions between ICRF and USNO-B1.0 are available on the reason of some errors: the regional differences
in positions between ICRF and USNO-B1.0; some errors of CCD frames reduction and possible structure
problems of some separate ERS.
Despite enough of reference stars of similar brightness to the researched objects, the received differences
have shown impossibility to use the USNO catalogues for determination link parameters owing to low accuracy
positions and proper motions.
In autumn 2003 the UCAC2 catalogue became available in separate areas of a zone of declinations up to
+52◦. A processing of received material was made using the reference stars from the UCAC2 [14]. Unfortunately,
the version UCAC2 we used has allowed us to process less half of available fields on reason of small field and
absence of high declination zone.
A distribution of differences ΔαO−R · cos δ = αO −αR and ΔδO−R = δO − δR with the UCAC2 catalogue is
shown in Fig. 3b. Only four optical counterparts out of 136 lie beyond 150 mas. There are no dependence of
the optical minus radio position differences as a function of right ascension and declination (see Figs. 4 and 5).
DETERMINATION OF PRELIMINARY ANGLES
BETWEEN OPTICAL AND RADIO REFERENCE FRAMES
In accordance with available observations the values of the angles between optical and radio reference frames
were calculated by known formulas:
335
a) as a function of right ascension b) as a function of declination
Figure 4. Optical minus radio differences ΔαO−R · cos δ for the ERS observed in Joint Project
a) as a function of right ascension b) as a function of declination
Figure 5. Optical minus radio differences ΔδO−R for the ERS observed in Joint Project
ΔαO−R · cos δ = ωx · sin δ · cosα + ωy · sin δ · sin α − ωz · cos δ,
ΔδO−R = −ωx · sinα + ωy · cosα,
(1)
where ΔαO−R = αO − αR and ΔδO−R = δO − δR are the ERS coordinate differences in optical and radio
reference frames; wx, wy, wz are the rotation angles about the x, y, z axes, respectively.
Taking into account all remarks shown above the angles’ values were determined from available observations
(Table 2). For comparison, the angles obtained by various authors are given [3, 10, 11, 15]. At last the Joint
Project results which were determined recently with the new UCAC2 catalogue are shown in Table 2.
Table 2. Optical-radio rotational parameters
Source ωx, mas ωy , mas ωz , mas N σ1, mas
Andrei et al. (1995), FK5 [2] −30±20 30±30 20±20 29 170
Kumkova et al. (1995), FK5 [3] 38±18 22±16 −17±16 78 –
FASTT (1997), FK5 [10] 3±5 25±5 16±4 689* 104
FASTT (1998), HC [11] −2.2±3.3 −2.2±3.4 3.3±2.9 689** –
Zacharias et al. (1999), ERL [15] −0.2±3.9 −5.4±3.9 −2.5±3.9 318 58
Joint Project (2003), UCAC2 −1.3±7.2 9.3±6.7 6.1±5.7 132 59
The column N gives number of ERS sources in the solution, 689*, 689** gives number of FK5 and HC stars,
respectively, determined in the ICRF using CCD observations with the FASTT; ωx, ωy, ωz are the rotation
angles with their standard errors; σ1 is the weight unit error.
It is to be noted that results obtained with the UCAC2 are similar to best. They have higher accuracy due
to good secondary reference star positions of the UCAC2.
336
The USNO-B1.0 is a convenient and perspective catalogue for reduction of CCD frames with a small size of
fields. It is necessary to complete investigations by processing of available observations using the USNO-B1.0
catalogue.
CONCLUSIONS
• At present, the observations of about 200 ERS obtained using the telescopes collaborated in Joint Project
are available for reduction.
• The best rotation parameters has been obtained in the system of a more precise catalogue like the UCAC2
on the accuracy level of ±6 mas.
Acknowledgements. Authors thanks are expressed to Norbert Zacharis and the UCAC team at USNO for
effective placing at our disposal new UCAC2 catalogue. This research has been partly supported by the Russian
Foundation of Basic Research (Grant No. 02-02-17076a).
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