Dubbed a 'Christmas miracle' by anxious astronomers, the massive, next-generation Jame Webb Space Telescope is finally on the launch pad, ready to go to space.

Axar.az reports that the telescope has been hit by months of launch delays, which followed years of delays to its construction, with its first launch date supposed to be in 2007.

The observatory is now set to take off on December 25, with a launch window between 07:20 ET (12:20 GMT) and 07:52 ET (12:52 GMT).

Ahead of the launch, it was loaded into the fairing of an Ariane 5 rocket and moved on to the launch pad at the Europeans Space Agency facility in French Guiana.

Live coverage of the launch will be shown on NASA's TV channel and website on Saturday, starting at 06:00 ET (11:00 GMT).