The season of evening ISS passes over Poland is slowly coming to an end. Saturday's observations will nevertheless be favourable due to the station's high brightness, and the first pass will run almost exactly through the zenith.
During this pass, the ISS will reach a brightness of –3.7 magnitude and a maximum altitude of 87°. The second pass will be lower and shorter, but it will take place under darker skies and remain visible from across the country.
The first ISS pass will reach an altitude of 87°
The International Space Station will appear at 21:32:20 at an altitude of 10° above the western horizon. It will then quickly rise towards the central part of the sky.
The ISS will reach its maximum altitude at 21:35:44. The station will then be 87° above the horizon in the south-western direction, just 3° from the zenith.
Its brightness will be –3.7 mag. Such a high culmination means that for the middle part of the pass, the station will be visible high above buildings, trees and other terrain obstacles.
After passing its highest point, the ISS will head towards the east-south-eastern part of the sky. The pass will end at 21:39:09, when the object descends to 10° above the horizon.
The entire pass will last 6 minutes and 49 seconds. The most important part of the observation will take place between 21:34 and 21:37, when the station will be high in the southern sky.
Visibility of the first pass depends on sky brightness
At 21:32, the sky over parts of Poland may still be noticeably brightened by late twilight. This applies especially to the northern and north-western regions of the country, where the Sun is less far below the horizon.
Conditions will improve towards the south-east. The farther south-east in Poland, the darker the sky will be during the pass and the greater the contrast between the ISS and the background.
However, a brightness of –3.7 mag should make it possible to spot the station even in a brightened sky. Observation should begin promptly, looking low above the western horizon.
The second pass will be lower and shorter
The second Saturday pass will begin at 23:09:19. The ISS will appear at an altitude of 10° above the western horizon and move towards the south-western part of the sky.
The maximum altitude will be 29°. The station will reach it at 23:12:18 in the south-western direction.
The predicted brightness of the second pass is –2.7 mag. The ISS will remain a distinct object visible to the naked eye, although its trajectory will be much lower than during the first observation.