Enter the place and local display zone
Use latitude and longitude for the observing location and choose its IANA time zone. The search start is explicitly UTC; the result table converts candidate times into the selected display zone. This separates an unambiguous calculation time from the clock your group will use.
Without weather, observer coordinates remain in the browser. Everyone can share the same cached NASA trajectory because it describes the station, not a personal location. The local calculation then determines how that trajectory appears from your coordinates.
Set a conservative skyline height
The minimum elevation can exclude a low horizon blocked by buildings or trees. It is one height for the whole skyline, not a survey of individual obstacles. A higher mask may shorten a candidate or remove a low pass entirely.
Directions use azimuth clockwise from north and an eight-point compass label. The sky diagram places the zenith at the center and the horizon at the outside. It describes where to look from the observer’s point of view, not a map of the station’s ground track.
Read the interval as a candidate
The station must be fully sunlit, the observer’s Sun below the chosen limit and the station above the mask. A listed interval can therefore cover only a portion of a full above-horizon pass. Ten-second midpoint samples make its boundaries approximate.
Choose a safe, accessible viewing place and arrive before the planned time. The tool cannot assess terrain, weather or local access. Record what you actually see on the card and keep a distinction between a predicted opportunity and a confirmed observation.