L'eclissi di Luna del 26 maggio 2021 da misure meridiane

The lunar eclipse of May 26, 2021 was not observable form Rome, Italy. Its footprints are, nevertheless, present in the meridian data measured on the windowsill. At 23:34 UT of May 26, the Moon shadow cast by the gnomon of 293 mm was 641±1.5 mm long; with the sameapparatus the Sun casted a 109.5±0.5 mm shadow at noon 11:07 UT of 29 May. The shadow's limit corresponds to the North limb of Moon and Sun; their centers are 16' lower. To have at least a partial eclipse the distance of the lunar limb from antihelion position should be ≤1.5°, the average radius of Earth's shadow at mean Moon's distance. On May 26th, the solar transit was at 11:07 UT, the Moon was in meridian 27 minutes after the local true midnight, i. e. the Moon passed the opposition of 7°, or 12 hours since its angular mean velocity is 0.5°/hour. The ecliptic is the orbit of the Sun, and 180+7 days after, the Sun at the meridian is 25.8° above Rome's horizon.The Moon 12 hours after the opposition on May 26th is at 24.6° and its ecliptic latitude is -1.2°±0.1°: indeed 12 hours before an eclipse occurred.