As NASA’s Juno spacecraft closes in for its Monday arrival at Jupiter, many other eyes are also staring at the solar system’s largest planet.

Data from about 25 observatories — including some of the largest on Earth, like the W. M. Keck Observatory in Hawaii, and in orbit around Earth, like the Hubble Space Telescope — will aid scientists in interpreting the data that Juno is expected to gather as it swoops close to the cloud tops of Jupiter over the next 20 months.

It has taken Juno nearly five years to reach this point in its journey.

“In just a few days, we’re about to arrive at Jupiter, and it’s hard to believe,” Scott Bolton, the mission’s principal investigator, said at a NASA news conference on Thursday.

Around last Friday, Juno crossed from interplanetary space into the magnetic bubble surrounding Jupiter that deflects the stream of particles from the sun known as the solar wind. “Inside that magnetosphere is Jupiter’s domain that’s filled with its particles,” Dr. Bolton said. “It has blocked out the sun’s particles.”