The Gedser Lighthouse was built in 1802 and before that a marking light made by a charcoal fire could be seen up to 10 kilometers from the shore that is out to the Gedser Reef Lightship

Could you correct the punctuation please?
The Gedser Lighthouse was built in 1802, and before that a marking light made by a charcoal fire could be seen up to 10 kilometers from the shore, that is out to the Gedser Reef Lightship.