Jupiter is now low in the evening sky,
only 35 degrees from the Sun, so that it will be hard to see Spica below it. The magnitudes of Jupiter and Spica are -1.7 and +1.0 – meaning that the star is 12 times dimmer.
They are closest (3.1°) at 1 Universal Time on Sep. 12, which for clocks in America is back in Sep. 11. In fact for the U.S. Central time zone it is 8 PM EDT, the time of our picture.
This is the second meeting of these two in the year. Back in February, Jupiter came to its stationary moment, about half a degree farther north of the star than it is now.
Detail from the chart of Jupiter for 2017.
Notice that, at that time, the place where Jupiter came to a standstill was north of Spica in right ascension – that is, parallel to the sloping lines marked “13h” and “30m” – but it never arrived north of Spica in ecliptic longitude, the framework of this chart. So there was a conjunction in right ascension on Jan, 20; then an appulse, or nearest approach, on Feb. 1, essentially the same as the moments on Feb. 6 when Jupiter was stationary; then a second conjunction in right ascension on Feb. 23.
After that, Jupiter was retrograding – appearing to move back westward as we overtook it – and was nearest (at opposition) in April, and, becoming more distant, began in June to resume apparent forward motion, while gradually being overtaken by the Sun.
View from 15° north of the ecliptic plane, showing the planets’ paths in September, and sightlines from Earth to Sun and Jupiter (and the other planets) at Sep. 12.
Jupiter is 6.24 astronomical units (Sun-Earth distances) from us, Spica about 260 light-years – about 3,150,000 times as far.