Development of a digital zenith telescope for advanced astrometry

Hanada, Hideo; Araki, Hiroshi; Tazawa, Seiichi; Tsuruta, Seiitsu; Noda, Hirotomo; Asari, Kazuyoshi; Sasaki, Sho; Funazaki, Ken-ichi; Satoh, Akira; Takahashi, Hideo; Kikuchi, Mamoru; Takahashi, Tomoe; Yamazaki, Atsumu; Ping, Jinsong; Kawano, Naoki; Petrova, Natalia; Gouda, Naoteru; Yano, Takeru; Yamada, Yoshiyuki; Niwa, Yasumasa; Kono, Yusuke; Iwata, T.

doi:10.1007/s11433-012-4673-1

Cited by 16 publications

(5 citation statements)

References 7 publications

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“…In part this may be due to a disparity in the number of observations; the larger Apollo 15 array collects 75% of the observations whereas the combined Apollo 11 and 14 arrays comprise 21%, but it also suggests that there may be some unmodeled effect on physical libration in longitude. Future measurements of physical librations could involve other techniques: differential radio tracking [ Bender , ; Gregnanin et al ., ] and a polar zenith telescope [ Hanada et al ., ; Petrova and Hanada , ] have been proposed.…”

Section: Future Investigationsmentioning

confidence: 99%

Tides on the Moon: Theory and determination of dissipation

2015

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Solid body tides on the Moon vary by about ±0.1 m each month. In addition to changes in shape, the Moon's gravity field and orientation in space are affected by tides. The tidal expressions for an elastic sphere are compact, but dissipation introduces modifications that depend on the forcing period. Consequently, a Fourier representation of the tide-raising potential is needed. A mathematical model for the distortion-caused tidal potential may be used for the analysis of precise spacecraft tracking data. Since tides affect gravitational torques on the Moon from the Earth's attraction, the lunar orientation is also affected. Expressions for five periodic perturbations of orientation are presented. The rheological properties of lunar materials determine how the Moon responds to different tidal periods. New lunar laser ranging solutions for the tidal orientation terms are presented. The quality factor Q is 38 ± 4 at 1 month, 41 ± 9 at 1 year, ≥74 at 3 years, and ≥58 at 6 years. The ranging results can be matched with absorption band models that peak at 120 days and single relaxation time models that peak at~100 days. Combined models are possibilities. Dissipation can modify laser ranging solutions; previously reported core flattening is too uncertain to be useful. Strong lunar tidal dissipation, modeled to arise in the deep hot mantle, appears to be from a region with radius ≥535 km. Classical Maxwell-type dissipation is too weak to detect at 3 and 6 year periods.

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Section: Future Investigationsmentioning

confidence: 99%

Tides on the Moon: Theory and determination of dissipation

2015

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“…in-situ observation). In recent years, the National Astronomical Observatory of Japan and JAXA (Japan Aerospace Exploration Agency) have once proposed a lunar attitude measurement program (ILOM) in which they try to put a photographic zenith tube (PZT) at the north pole of the Moon as an attempt to realize in-situ observation of rotation of the Moon (Hanada et al 2012). Limited by the lunar landing mission, it has not been successfully implemented.…”

Section: Introductionmentioning

confidence: 99%

A new telescope with three fields of view to measure the orientation parameters of the Moon and terrestrial planets

Sun

Huang

et al. 2021

Res. Astron. Astrophys.

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For lots of scientific questions about lunar physics deep inside the Moon, in-situ observation on lunar physical libration is one of the most potential ways. In this paper, we propose a brand new optical telescope functioned with simultaneously observing multiple (here there are three) fields of view (FOVs) for in-situ observation of lunar physical libration. The telescope can be placed at any place with any attitude on the Moon and do not require manned install, control or operation. It passively, continuously and simultaneously observe stars in three FOVs along with rotation of the Moon. Libration is to be measured and studied from celestial motion of the directions of three FOVs from image processing. The concept and design of this telescope are firstly introduced in this paper. The principle and feasibility of the method of in-situ observation are also demonstrated. From simulation, precision of the determined lunar physical libration is expected to be several milliarcsecs, about two orders of magnitude better than the current precision of libration by lunar laser ranging observation. Libration data with milliarcsec precision level can play a valuable role in the study of the physics and dynamics of the interior of the Moon. This telescope can also be applied to observe the rotation of other terrestrial planets like Mars.

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“…In the ~1970s, photographic zenith cameras were developed to accelerate the field observation (e.g., Wissel 1982, Wildermann 1988, Bürki 1989). Since the beginning of the 21 st century, astrogeodetic observations are mostly carried out with efficient and automated digital instruments such as digital zenith cameras (e.g., Kudrys 2009, Hirt et al 2010aAbele et al 2012, Halicioglu et al 2012, Hanada et al 2012, Wang et al 2014, Guillaume 2015 or imaging theodolites (Guillaume et al 2012, Tóth and Völgyesi 2016, Hauk et al 2017, Schack et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Reactivation of the Venezuelan vertical deflection data set from classical astrogeodetic observations

Hirt

Wildermann

2018

Journal of South American Earth Sciences

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Highlights  Astrogeodetic vertical deflections (observed geoid slopes) are rare in South America  A classical vertical deflection dataset exists for Cordillera de Mérida (Venezuelan Andes)  Transformation to current reference frames to be compatible with modern geo-products  Deflections reach amplitudes of ~60 arc-seconds in this rugged mountain area  RMS-agreement of 2 arc-seconds with predictions from GGMplus. Data freely available.

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Development of a digital zenith telescope for advanced astrometry

Cited by 16 publications

References 7 publications

Tides on the Moon: Theory and determination of dissipation

Tides on the Moon: Theory and determination of dissipation

A new telescope with three fields of view to measure the orientation parameters of the Moon and terrestrial planets

Reactivation of the Venezuelan vertical deflection data set from classical astrogeodetic observations

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