On July 23rd I printed off a list predictions for ISS passes visible from Cork. Becuase of cloud cover I only managed to see 1 pass until last night - 26th. The prediction was for 22:14 with a magnitude of -2.4. I waited, and waited but no sign of ISS until 22:21 when it appeared.
I checked the time again and confirmed the prediction of 22:14.
This morning I went back on to the Heavens Above website and viewed the predictions for the next 7 days. When I compared the list to the one I printed on the 34rd, all the times were out .. starting at about 5 minutes and finishing with August where the original prediction is 23 minutes before what the website says this morning!
Is this a regular occurence - do they revise the times on a daily basis ?
John, it's interesting you should mention this as we've had a similar discussion elsewhere. What we do know is that the ISS orbit decays and it is periodically kicked back up a bit by the Shuttle, so the timings would change. We don't know how H-A accommodates this but like you, we have observed passes being a little later than advertised.
John, it's interesting you should mention this as we've had a similar discussion elsewhere. What we do know is that the ISS orbit decays and it is periodically kicked back up a bit by the Shuttle, so the timings would change. We don't know how H-A accommodates this but like you, we have observed passes being a little later than advertised.
  