Why different times such a 4 minutes 3 minutes and 2 minute sightings of Spacestation

[wendilla]

I normally post on chatterbank the times for the ISS when overhead in the uk as some people did not know that they could see it. I have read lots about it but what I would like to know is that when there is a 4 minute sighting it can be seen all the way across the sky but when it is a 2 and a 1 minute sighting it disappears halfway across. Has this got something to do with how the sun shines on it or is it to do with the shadow of the earth. Not very technichal on this subject so easy to understand replies please.Thanks

[ABerrant]

As the ISS passes through the Earth's shadow there is no sunlight to be reflected by it, thus it disappears from normal viewing by the naked eye.

[wendilla]

Thanks for answer and also just read because of stations orbit and rotation of the earth , sightings vary.

[maggieb66]

What time tonight Wendilla

[boxtops]

I wondered that wendilla, a couple of nights ago it disappeared completely well before getting to my normal horizon (i.e. next door's roof)

[Teddio]

When the ISS sighting is a few hours after local sunset it will enter the Earth's shadow earlier. From UK latitudes it is never possible to see the ISS at say 1am as it will be in the Earth's shadow. Watch carefully as the ISS "disappears", you should see it fade and turn reddish in colour. From the ISS the astronauts will see a rapid sunset as the Sun plunges below their horizon.

[wendilla]

Thank you for replies .very interesting