GPS IIF-1 over Chicago tonight
Pass predictions for Chicago, IL.
Next visible pass
Wed, Sep 9, 11:48 AM
Peak elevation 36.80° · rises SE · sets NE
Tracking: GPS BIIF-1 (PRN 25) (NORAD 36585)
7-day pass forecast
| Date | Time | Peak elev | Rises | Sets |
|---|---|---|---|---|
| Sep 9 | 11:48 AM | 36.80° | SE | NE |
| Sep 10 | 2:39 AM | 39.53° | NW | SW |
| Sep 10 | 11:44 AM | 36.80° | SE | NE |
| Sep 11 | 2:35 AM | 39.54° | NW | SW |
| Sep 11 | 11:40 AM | 36.80° | SE | NE |
| Sep 12 | 2:31 AM | 39.54° | NW | SW |
| Sep 12 | 11:35 AM | 36.80° | SE | NE |
How to spot GPS IIF-1 from Chicago
GPS navigation satellite in MEO at ~20,200 km — visible with binoculars in the right window.
- Look in the direction listed — passes start near the horizon and arc across the sky.
- Peak elevation matters — a 60°+ peak means it'll go nearly overhead; under 30° stays low.
- Best viewing is in the 90 minutes after sunset or before sunrise — the satellite is sunlit while you're in shadow.
- No equipment needed for bright passes — the ISS at peak rivals Venus.
Going to look up?
For fainter satellites you'll want 7×50 or 10×50 binoculars. A pair of Celestron SkyMaster binoculars is the consensus pick. Affiliate placement — replace with your affiliate link.
Pass alerts on your phone
Browser push, no email needed. We'll notify you 30 minutes before GPS IIF-1 is visible from Chicago.
Prefer email?
One email tonight before GPS IIF-1 is visible, never more than 2/week.