Quote:
Originally Posted by MortonH
Yesterday SS (Android basic version) predicted that the GRS would be central around 8:30pm and that Callisto would begin a transit around the same time.
When I actually observed it last night I noticed that Callisto didn't begin to pass in front of Jupiter until at least 30 minutes after SS showed the event starting.
I checked my location and time settings and even swapped between using the GPS setting and manually selecting Sydney - no change.
Is this normal or do we expect SS to be more accurate with its timings?
I didn't think to compare it with my Mac version.
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SS is possibly showing the event time as it would be seen at Jupiter without taking the time it takes for the light to get back to Earth.
Finding that Jupiter moon transits were being seen at varying times was how
Ole Romer's measurements lead to the first scientifically determined estimate of the speed of light.
You could ask the question on Y!.
Note: I know Romer's name is spelled with a o with a / through it, but non ACSII characters stuff up my Firefox.