OLED is an observational project proposed by the Federación de Asociaciones Astronomicas de España and the Société Astronomique de France, aimed at amateur observers interested in measuring lunar occultations of double stars and using photometric techniques applied to these events. These techniques allow to obtain the light curve of a double star occultation, and from it, the measurement of its parameters, separation and position angle, with data obtained from two or more observers. Data from single observers are also valuable. It is therefore a collaborative project, like other projects such as asteroidal occultations. In the case of lunar occultations the events are not local phenomena, but their visibility is spread across a large geographical area, which makes things easier since it is not necessary to travel to specific locations: lunar occultations can be observed from our usual observing site. This aspect renders lunar occultation work ideal for international collaboration.
The objective is to study close double stars (which are more difficult to measure with other techniques), especially those with only one measurement or with few historical measurements.
Several occultations of double stars are visible from a given station every month. This collaborative project aims to initially analyze easy stars, and then expand to a larger set of stars with the aim of obtaining astrometrical data that can be used to calculate or improve their orbits.
Apart from the ongoing observation campaign, the project also deals with special campaigns. For example, a campaign to study duplicity of stars from the Gaia DR3 catalogue that are suspected of being close double has been launched recently. This taks is essential to help extract information from the massive amount of data gathered by the Gaia satellite.
Observation does not require sophisticated observation techniques, and any amateur astronomer with equipment that has tracking and digital or analog image capture system with a good time base can contribute interesting data.
If you would like to participate and/or learn more about this project, please have a look at this website (especially the AIMS, PROCEDURES and TECHNIQUES sections), and write to the coordinators, Enrique Velasco (enrique.velasco@uam.es), Spain, or Philippe Laurent (apilaure_astro@yahoo.fr), France.
