The chart above displays the setting time of Venus (green curve) compared to sunset. The three phases of twilight are displayed as well. The setting time differences are displayed for bright stars near the ecliptic as well as other bright planets. The moonset interval is displayed with circles. The rising time difference – compared to sunset – is displayed for Jupiter and Saturn as well. When the planets rise at sunset, they are at opposition.
Venus as an Evening Star, semi-technical summary.
Saturn’s opposition with Venus is displayed as a brown box on the Saturn Rising line. A yellow box on the Jupiter Rising line indicates a similar event, Venus – Jupiter opposition. In the evening, when two planets are at opposition, opposite sides of Earth, one is rising as the other sets. A week or so after these dates Saturn, then Jupiter, appear in the eastern sky as Venus shines from the west. In this study of Venus, this trio is in the sky together during evening hours until nearly the end of its evening appearance during early 2022.
When the Venus curve crosses another line, Venus and that celestial object set at the same time. Conjunctions occur near this date. White boxes on the charts indicate conjunctions with stars and other planets. The yellow triangle, with the letters “GE,” indicates the greatest elongation dates of Venus and Mercury.
The setting chart is from data by the U.S. Naval Observatory’s Multiyear Interactive Computer Almanac (MICA) for Chicago, Illinois. Make any appropriate adjustments for different latitudes. Time intervals after sunset are used in the following notes for observers to determine the appropriate observing clock time at their locations.
Newly released analysis from the Mars Reconnaissance Orbiter shows that the Arabia Terra region on Mars experienced powerful volcanic eruptions.
September 30, 2021: An hour before sunrise, the crescent moon is near the Gemini Twins.
September 29, 2021: The thick crescent moon is in the southeast before sunrise, approaching the middle of Gemini. The evening planet pack is visible after sunset.
September 28, 2021: This morning the moon, as it approaches its Last Quarter phase, is high in the south at the Gemini – Taurus border. The evening planet pack – Venus, Jupiter, and Saturn – brightly shine after sunset.
September 27, 2021: Before sunrise this morning, the bright moon seems caught between the horns of Taurus, Elnath and Zeta Tauri. The planet pack, Venus, Jupiter, and Saturn, are visible after sundown.