If the stormy weather blocks the sighting of the very rare annular solar eclipse tomorrow morning, we will not get to see the golden ring again.
That explains why astronomy buffs are hoping the cloud and thunderstorms forecast to loom over Hong Kong will abate.
'The weather certainly isn't ideal for viewing a rare eclipse like this,' said the Observatory's scientific officer Woo Wang-chun, who will record the phenomenon with Space Museum staff for a live public webcast, weather permitting.
'Every year there are two to three eclipses visible in different parts of the world,' Woo said. 'What's so special about this one is it's an annular solar eclipse, meaning the sun will appear as a very bright ring surrounding the moon.'
Annular solar eclipses are extremely rare in Hong Kong - the last one occurred in 1958 and the next will be more than 300 years away - in 2320.
When the sun rises at 5.41am tomorrow, the eclipse will already have begun and it will run until 7.16am.
The period when the moon completely blocks the sun - known as totality - will last about 31/2 minutes from 6.06am. This is more than twice as long as the last one.