Petre Paraschiv

ABSTRACT Modern time measurements in Romania started in 1967 with the installation of Rohde & Schwarz quartz clocks. The paper shows both the evolution of these measurements and the stability of the system, which became a few times better than in the beginning, 35 years ago. The evolution of the original R1, R2, R3, R4 oscillators was analyzed. After 1994, the receivers were connected to a digital chronometer, in order to perform the acquisition of the measuring data. New comparisons of R1, R2, R3 with M1, M2, M3 quartz clocks and GNST GPS receiver were made.

International audienceAn wide range, all-sky camera network is an effective infrastructure for the detection of atmospheric entries of natural (meteoroids) or artificial bodies (space debris). The Meteorites Orbits Reconstruction by Optical Imaging (MOROI) is an allsky network operated by the Astronomical Institute of the Romanian Academy. Here we present the overall architecture of the network that became operational on mid-2017 and the preliminary results on atmospheric trajectory and orbit reconstruction of multistation events. The 20-station network is expected to be fully operational by the end of 2018

In Bucharest and Belogradchik Astronomical Observatories were performed astrometric observations of ICRF defining and candidates radio-stars. In the first step we performed a modernization of the 60 cm telescope in Belogradchik - Bulgaria, in order to be able to reach 20-th magnitude. The paper describes the achievement of this task and the methods of observation and reduction of data. The results are stored in an astrometric data-base containing also the reference system of the quasars.

In Bucharest was installed a Danjon astrolabe, transferred from the Royal Observatory of Brussels. This paper deals with the improvements brought to this instrument in order to gain stability, observation acccuracy and efficiency. The changing of the transparent prism with a Zerodur reflecting one, the new dual task of this astronomical instrument (self-collimating system and star tracker) and the acquisition of images using a CCD camera are the technical solutions of the modernisation project.

Modern time measurements in Romania started in 1967 with the installation of Rohde & Schwarz quartz clocks. The paper shows both the evolution of these measurements and the stability of the system, which became a few times better than in the beginning, 35 years ago. The evolution of the original R1, R2, R3, R4 oscillators was analyzed. After 1994, the receivers were connected to a digital chronometer, in order to perform the acquisition of the measuring data. New comparisons of R1, R2, R3 with M1, M2, M3 quartz clocks and GNST GPS receiver were made.

In Bucharest and Belogradchik Astronomical Observatories were performed astrometric observations of ICRF defining and candidates radio-stars. In the first step we performed a modernization of the 60 cm telescope in Belogradchik - Bulgaria, in order to be able to reach 20-th magnitude. The paper describes the achievement of this task and the methods of observation and reduction of data. The results are stored in an astrometric data-base containing also the reference system of the quasars.

In Bucharest was installed a Danjon astrolabe, transferred from the Royal Observatory of Brussels. This paper deals with the improvements brought to this instrument in order to gain stability, observation acccuracy and efficiency. The changing of the transparent prism with a Zerodur reflecting one, the new dual task of this astronomical instrument (self-collimating system and star tracker) and the acquisition of images using a CCD camera are the technical solutions of the modernisation project.

Modern time measurements in Romania started in 1967 with the installation of Rohde & Schwarz quartz clocks. The paper shows both the evolution of these measurements and the stability of the system, which became a few times better than in the beginning, 35 years ago. The evolution of the original R1, R2, R3, R4 oscillators was analyzed. After 1994, the receivers were connected to a digital chronometer, in order to perform the acquisition of the measuring data. New comparisons of R1, R2, R3 with M1, M2, M3 quartz clocks and GNST GPS receiver were made.

The Danjon astrolabe transferred from the Royal Observatory of Brussels to Bucharest has been upgraded. The wollaston micrometer was replaced by an illuminated reticle that serves for the determination of astrolabe tilt versus the local vertical (the mercury pool). The transparent prism was replaced with a reflecting one, cut from a Zerodur block; it contains two pieces glued at the contact surfaces. The left piece has the reflecting surface tilted at 45 degrees to the optical axis of the astrolabe, and is the autocollimating mirror. The right piece has the reflecting surface tilted at 22.5 degrees to the astrolabe objective, and serves for star observations. The camera used is a COHU 4710 (borrowed from Paris Observatory, DANOF). The images are obtained in the CINE-CCD mode. The software was written in Pascal, based on advice received from Dr. F. Chollet. In the first step we have determined the inner parameters of the new astrolabe. We hope to observe by this technique stars faint...

The Danjon astrolabe transferred from the Royal Observatory of Brussels to Bucharest has been upgraded. The wollaston micrometer was replaced by an illuminated reticle that serves for the determination of astrolabe tilt versus the local vertical (the mercury pool). The transparent prism was replaced with a reflecting one, cut from a Zerodur block; it contains two pieces glued at the contact surfaces. The left piece has the reflecting surface tilted at 45 degrees to the optical axis of the astrolabe, and is the autocollimating mirror. The right piece has the reflecting surface tilted at 22.5 degrees to the astrolabe objective, and serves for star observations. The camera used is a COHU 4710 (borrowed from Paris Observatory, DANOF). The images are obtained in the CINE-CCD mode. The software was written in Pascal, based on advice received from Dr. F. Chollet. In the first step we have determined the inner parameters of the new astrolabe. We hope to observe by this technique stars faint...

In the next observation campaign of mutual phenomena of Jupiter satellites, a Meade telescope with CCD will be used beside the other instruments already in function at Bucharest Observatory. The installation of the instrument began with different tests performed with the CCD camera. This includes laboratory tests, observations of stars and of planetary satellites. Different image acquisition and data storage software were used.

For detecting and observing NEOs for astrometrical purposes, we prepared a special observing system. We mean a special equipped instrument and a specific CCD method of identifying the object and data acquisition. Our efforts were concentrated on both subjects: the topic shows the improvements made to the instrument to the pointing device, the observation system CCD camera / accessories and the results obtained.

In the next observation campaign of mutual phenomena of Jupiter satellites, a Meade telescope with CCD will be used beside the other instruments already in function at Bucharest Observatory. The installation of the instrument began with different tests performed with the CCD camera. This includes laboratory tests, observations of stars and of planetary satellites. Different image acquisition and data storage software were used.

Astronomical Institute of Romanian Academy initiated this project in 2005. The results of researches related to the construction of mechanic systems and the proposed astrometric tasks will be finished in 2008. The module PROTEL is a result of several research groups and it will perform astrometric control observations remotely.

The Danjon astrolabe transferred from the Royal Observatory of Brussels to Bucharest has been upgraded. The wollaston micrometer was replaced by an illuminated reticle that serves for the determination of astrolabe tilt versus the local vertical (the mercury pool). The transparent prism was replaced with a reflecting one, cut from a Zerodur block; it contains two pieces glued at the contact surfaces. The left piece has the reflecting surface tilted at 45 degrees to the optical axis of the astrolabe, and is the autocollimating mirror. The right piece has the reflecting surface tilted at 22.5 degrees to the astrolabe objective, and serves for star observations. The camera used is a COHU 4710 (borrowed from Paris Observatory, DANOF). The images are obtained in the CINE-CCD mode. The software was written in Pascal, based on advice received from Dr. F. Chollet. In the first step we have determined the inner parameters of the new astrolabe. We hope to observe by this technique stars fainter than 8 mag with a new intensified CCD camera.

In the Bucharest Astronomical Observatory we started an observational program aiming at the improvement of positions for optical counterparts of ICRF radiosources by narrow-field CCD observations and the accurate densification of the optical frame and extension to fainter magnitudes. We also estimated the errors in UCAC2, USNO B1.0 and 2MASS catalogs by CCD observations of ICRF sources and we prepared a catalog of intermediary reference stars around ICRF optical counterparts. Comparison with three independent telescope/catalog datasets shows that the precision obtained here represents an important improvement on previous works.