Narrative:

[Jump plane] was releasing high altitude high opening parachute operations VFR at 17;500 feet MSL. Releasing jumpers about 5NM southwest of ZZZ. Estimated time in the air of the jumpers was 10 minutes. All traffic VFR and IFR was aware of this and kept away from the operation. On the last release he began a rapid descent back into ZZZ and notified to me that the parachutes would take about 10 minutes to get down to the ground. I terminated flight following and began to notice the primary targets from the radar slowly move from the release point; back to ZZZ airport. About 5 minutes after the release; [the jump plane] was gone and had probably landed at the airport but I noticed an un-verified VFR target (aircraft X) on the radar scope that was about 5 miles northeast of ZZZ and due south-bound with an altitude readout of 7;500 feet (unverified).the landing zones at ZZZ are located just east of the runway and looked like they might be an issue with aircraft X so I made a call in the blind about the parachute operations in the area and tried giving this aircraft a warning and asked for them to move further east and away from the operation. This attempt was met with no response and another call in the blind was made as the aircraft got closer to the primary targets; now just south of ZZZ that I assumed were the parachutes. The aircraft was in the middle of what I remember to be about 5 different targets before I noticed a hard left turn by the aircraft that took them east. The jump operation was at night and I imagine the jumpers were very difficult to see; a few different pilots on frequency at the time actually asked me to confirm that jump operations were occurring at the time; in disbelief that they would do this at night with low visibility. It's a VFR operation and NOTAMS are already in place to warn aircraft of the operation at ZZZ. The jump aircraft descends immediately after the release; the only thing I can think of to warn of jumpers at night to other aircraft would be for the jump aircraft to follow the jumpers down to a lower altitude before changing to local frequency. If I could call this unverified traffic to the jump plane and give a position report of potential conflict; they might be able to warn off unsuspecting aircraft either through flight maneuvers or local radio messages.

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Original NASA ASRS Text

Title: Enroute Controller reported observing a VFR aircraft take evasive action to avoid parachute jumpers.

Narrative: [Jump plane] was releasing High Altitude High Opening parachute operations VFR at 17;500 feet MSL. Releasing jumpers about 5NM southwest of ZZZ. Estimated time in the air of the jumpers was 10 minutes. All traffic VFR and IFR was aware of this and kept away from the operation. On the last release he began a rapid descent back into ZZZ and notified to me that the parachutes would take about 10 minutes to get down to the ground. I terminated flight following and began to notice the primary targets from the radar slowly move from the release point; back to ZZZ airport. About 5 minutes after the release; [the jump plane] was gone and had probably landed at the airport but I noticed an un-verified VFR target (Aircraft X) on the radar scope that was about 5 miles northeast of ZZZ and due south-bound with an altitude readout of 7;500 feet (unverified).The landing zones at ZZZ are located just east of the runway and looked like they might be an issue with Aircraft X so I made a call in the blind about the parachute operations in the area and tried giving this aircraft a warning and asked for them to move further east and away from the operation. This attempt was met with no response and another call in the blind was made as the aircraft got closer to the primary targets; now just south of ZZZ that I assumed were the parachutes. The aircraft was in the middle of what I remember to be about 5 different targets before I noticed a hard left turn by the aircraft that took them east. The jump operation was at night and I imagine the jumpers were very difficult to see; a few different pilots on frequency at the time actually asked me to confirm that jump operations were occurring at the time; in disbelief that they would do this at night with low visibility. It's a VFR operation and NOTAMS are already in place to warn aircraft of the operation at ZZZ. The jump aircraft descends immediately after the release; the only thing I can think of to warn of jumpers at night to other aircraft would be for the jump aircraft to follow the jumpers down to a lower altitude before changing to local frequency. If I could call this unverified traffic to the jump plane and give a position report of potential conflict; they might be able to warn off unsuspecting aircraft either through flight maneuvers or local radio messages.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.