Metrology for AGP &amp;#x2014; Astrometric Gravitation Probe

Gai, M.; Vecchiato, Alberto; Busonero, D.; Riva, A.; Lattanzi, M. G.; Pisani, Marco

doi:10.1109/metroaerospace.2015.7180677

Cited by 3 publications

(4 citation statements)

References 29 publications

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“…In Gaia, a complex optical setup is required to inject reference laser beams into the two telescopes without introducing external errors. In a single telescope system, the telescope itself can be used in a sort of auto-collimation scheme, 5,31 as depicted in Fig. 10: photons are injected close to the focal plane, and the return beam is re-imaged in the conjugated position, after a back-and-forth travel through the optical system thanks to a retro-reflecting mirror.…”

Section: Metrology Embedded In Telescopementioning

confidence: 99%

“…ASTRA is a collaboration between the Italian Institute for Astrophysics (INAF), in particular the astrometric team at the Astrophysical Observatory of Turin (OATo), and the Shanghai Astronomical Observatory (SHAO, Chinese Academy of Sciences -CAS), under the auspices of their respective Ministries, in the framework of the Scientific and Technological Cooperation Agreement between China and Italy. The project, started in late 2019, builds on a long collaboration between the teams in the field of high precision astrometry, in particular on materialization of the absolute reference frame (APOP, 1 ), the astrometry mission proposal GAME (Gravitation Astrometric Measurement Experiment) to ESA, 2,3,4 its 2015 AGP (Astrometric Gravitation Probe) rendition, 5 and the ongoing experience on Gaia. 6,7,8 ASTRA also aims at fostering and consolidating national and international collaborations on astronomical and interdisciplinary research related to astrometric advancement.…”

Section: Introductionmentioning

confidence: 99%

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The ASTRA project: a doorway to future astrometry

Gai

Lattanzi

et al. 2020

Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV

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Astrometric Science and Technology Roadmap for Astrophysics (ASTRA) is a bilateral cooperation between China and Italy with the goal of consolidating astrometric measurement concepts and technologies. In particular, the objectives include critical analysis of the Gaia methodology and performance, as well as principle demonstration experiments aimed at future innovative astrometric applications requiring high precision over large angular separations (one to 180 degrees). Such measurement technologies will be the building blocks for future instrumentation focused on the "great questions" of modern cosmology, like General Relativity validity (including Dark Matter and Dark Energy behavior), formation and evolution of structure like proto-galaxies, and planetary systems formation in bio compatibles environments. We describe three principle demonstration tests designed to address some of the potential showstoppers for high astrometric precision experiments. The three tests are focused on the key concepts of multiple fields telescopes, astrometric metrology and very fine sub-pixel precision (goal: < 1/2000 pixel) in white light.

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Section: Metrology Embedded In Telescopementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The ASTRA project: a doorway to future astrometry

Gai

Lattanzi

et al. 2020

Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV

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“…One significant example in this sense is the Astrometric Gravitation Probe (AGP) project Gai & et al 2015), a concept for a space mission whose main scientific goal is the determination of the γ and β parameters of the PPN framework at the ∼ 10 −8 and ∼ 10 −6 level respectively. In particular, the estimation of β would be obtained by an astrometric reconstruction of the orbit of Mercury, and possibily of some selected NEOs.…”

Section: Astrometric Gravitation Probe Projectmentioning

confidence: 99%

“…Techniques of differential astrometry like the one described in this work and developed for the GAREQ experiment can be conveniently applied in other astrometric experiments involving astrometric tests of gravity theories. One significant example in this sense is the AGP project (Gai et al 2015;, a concept for a space mission whose main scientific goal is the determination of the γ and β parameters of the PPN framework at the ∼10 −8 and ∼10 −6 level respectively. In particular, the estimation of β would be obtained by an astrometric reconstruction of the orbit of Mercury, and possibily of some selected NEOs.…”

Section: Astrometric Gravitation Probe (Agp) Projectmentioning

confidence: 99%

The Short-term Stability of a Simulated Differential Astrometric Reference Frame in theGaiaEra

Abbas

Bucciarelli

Lattanzi

et al. 2017

PASP

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We use methods of differential astrometry to construct a small field inertial reference frame stable at the micro-arcsecond level. Such a high level of astrometric precision can be expected with the end-of-mission standard errors to be achieved with the Gaia space satellite using global astrometry. We harness Gaia measurements of field angles and look at the influence of the number of reference stars and the star's magnitude as well as astrometric systematics on the total error budget with the help of Gaia-like simulations around the Ecliptic Pole in a differential astrometric scenario. We find that the systematic errors are modeled and reliably estimated to the µas level even in fields with a modest number of 37 stars with G <13 mag over a 0.24 sq.degs. field of view for short time scales of the order of a day with high-cadence observations such as those around the North Ecliptic Pole during the EPSL scanning mode of Gaia for a perfect instrument. The inclusion of the geometric instrument model over such short time scales accounting for large-scale calibrations requires fainter stars down to G = 14 mag without diminishing the accuracy of the reference frame. We discuss several future perspectives of utilizing this methodology over different and longer timescales.

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Astrometric Precision Tests on TESS Data

Gai

Vecchiato

Riva

et al. 2022

PASP

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Astrometry at or below the microarcsec level with an imaging telescope assumes that the uncertainty on the location of an unresolved source can be an arbitrarily small fraction of the detector pixel, given a sufficient photon budget. This paper investigates the geometric limiting precision, in terms of CCD pixel fraction, achieved by a large set of star field images, selected among the publicly available science data of the Transiting Exoplanet Survey Satellite (TESS) mission. The statistics of the distance between selected bright stars (G ≃ 5 mag), in pixel units, is evaluated, using the position estimate provided in the TESS light curve files. The dispersion of coordinate differences appears to be affected by long term variation and noisy periods, at the level of 0.01 pixel. The residuals with respect to low-pass filtered data (tracing the secular evolution), which are interpreted as the experimental astrometric noise, reach the level of a few milli-pixel or below, down to 1/5900 pixel. Saturated images are present, evidencing that the astrometric precision is mostly preserved across the CCD columns, whereas it features a graceful degradation in the along column direction. The cumulative performance of the image set is a few micropixel across columns, or a few 10 μpx along columns. The idea of astrometric precision down to a small fraction of a CCD pixel, given sufficient signal to noise ratio, is confirmed by real data from an in-flight science instrument to the 10−6 pixel level. Implications for future high precision astrometry missions are briefly discussed.

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Metrology for AGP — Astrometric Gravitation Probe

Cited by 3 publications

References 29 publications

The ASTRA project: a doorway to future astrometry

The ASTRA project: a doorway to future astrometry

The Short-term Stability of a Simulated Differential Astrometric Reference Frame in theGaiaEra

Astrometric Precision Tests on TESS Data

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