Joachim Gripp | Searcharxiv

arXiv2021

Appulses of Jupiter and Saturn

The latest conjunction of Jupiter and Saturn occurred at an optical distance of 6 arc minutes on 21 December 2020. We re-analysed all encounters of these two planets between -1000 and +3000 CE, as the extraordinary ones (<10$^{\prime}$) take place near the line of nodes every 400 years. An occultation of their discs did not and will not happen within the historical time span of $\pm$5,000 years around now. When viewed from Neptune though, there will be an occultation in 2046.

physics.pop-ph↗

arXiv2020

Hierarchical Eclipses

The obscuration of a celestial body that covers another one in the background will be called a ``hierarchical eclipse''. The most obvious case is that a star or a planet will be hidden from sight by the moon during a lunar eclipse. Four objects of the solar system will line up then. We investigate this phenomenon with respect to the region of visibility and periodicity. There exists a parallax field constraining the chances for observation. A historic account from the Middle Ages is preserved that we analyse from different viewing angles. Furthermore, we provide a list of events from 0 to 4000 AD. From this, it is apparent that Jupiter is most often involved in such spectacles because its orbit inclination is small. High-inclination orbits reduce the probability to have a coincidence of an occultation of that object with a lunar eclipse.

physics.pop-ph↗