The Reflecting Heliometer of Rio de Janeiro after 6 Years of Activity

TL;DR

The Reflecting Heliometer of Rio de Janeiro has been operational since 2011, achieving high-precision measurements of solar angles with minimal systematic errors, supporting ground-based astrometric programs.

Contribution

This paper reports six years of operational data demonstrating the heliometer's precision, stability, and independence from meteorological conditions, validating its performance for solar astrometry.

Findings

Achieved measurement accuracy of a few tens of milli-arcseconds.

Maintained constancy of the basic heliometric angle over time.

Operated reliably without systematic deviations or error amplification.

Abstract

Started its regular, daily operational phase in 2011 and installed in 2009 by the occasion of the Symp264 in the XXVII IAU GA at Rio de Janeiro, the results so far obtained show that the Heliometer of the Observatorio Nacional fulfilled its planed performance of single measurement to the level of few tens of milli-arcsecond, freely pivoting around the heliolatitudes without systematic deviations or error enhancement. We present and discuss the astrometric additions required on ground based astronomic programs. We also discuss instrumental and observations terms, namely the constancy of the basic heliometric angle, against which the measurements are made, and the independence to meteorological and pointing conditions.