Satellite Passes and the ISS from Guyana
The brightest "star" that moves may be a spacecraft, if it is sunlit and your sky is dark enough.
Low-Earth-orbit satellites reflect sunlight. You see them when you are in darkness (or twilight) and the satellite is still lit, classic evening and morning passes. Mid-night eclipses are common: the craft flies through Earth's shadow and fades out.
ISS specifics
The International Space Station is often as bright as (or brighter than) Venus at good elevations. From ~6°N:
- Passes can go high overhead depending on the orbit plane that week.
- Compass azimuth at rise matters, face the predicted start bearing.
- Magnitude estimates are approximate; haze and light pollution dim the view.
Use ISS Pass Predictor for times, badges (visible / twilight / daylight / near Sun / eclipsed), and sky path simulation.
Reading visibility flags
| Kind | Meaning | |------|---------| | Visible | Best chance for naked-eye spotting | | Twilight | Sky still brightening/darkening, still often easy for ISS | | Daylight | Above horizon but daytime sky usually wins | | Near Sun | Geometry unsafe/hard, do not hunt near the Sun | | Eclipsed | In shadow, typically not a bright streak |
Photography tips
- Wide lens, high ISO, 1-5 s trials for trails; or video for live view.
- Include a landmark for scale.
- Stacking many short frames can show a dashed path.
Limits
TLEs age; refresh predictions for passes days out. Weather still cancels. Iridium flares of old are mostly gone; many dimmer sats need darker sites.
Next
- How-to: ISS Pass Predictor
- Weather: Stargazing Weather