International Space Station

The International Space Station is now the brightest object in the night sky except for the moon. To see an artist’s conception of the multi-year assembly process click here. It circles the earth every 1 hour and 36 minutes. Orbiting at 250 miles up, it can be easily seen if it passes within 500 miles of here. Still, viewable passes are not frequent. Its orbit covers the whole earth between 52 degrees north and south latitudes. And to be viewable the pass must be shortly after sunset or just before sunrise. If the pass were in the middle of the night the earth itself would shadow it from the sun which, unlike stars, is its only illumination. Solar panels added to the station in recent years have made it more and more reflective.

The cycling of the many factors affecting passes results in about two consecutive weeks of each month in which there are no viewable passes at all. Then for a week or so they will be clustered in the predawn hours. Following that will be a week or so of more conveniently viewable passes – between sunset and about midnight. Clicking on the attached link brings up a schedule that looks like this:  

SATELLITE	LOCAL DATE/TIME	DURATION (MIN)	MAX ELEV (DEG)	APPROACH (DEG-DIR)	DEPARTURE (DEG-DIR)
ISS	Thu Aug 02/03:32 AM	4	82	32 above WNW	10 above ESE

The time and date given is when the station will appear at the “Approach” position. Here, on Thursday, August 2, at 3:32am it will appear 32 degrees above the west northwest horizon. It will then reach a maximum elevation of 82 degrees (nearly straight up) before setting 10 degrees above the east-southeast horizon. The entire pass will last four minutes.