NASA has launched a mission from Cape Canaveral in Florida to observe the Sun.
It was the second lift-off attempt after a postponement due to high winds on Wednesday.
The BBC reports the observatory is designed to acquire detailed images of the Sun to explain variation in its activity.
Activity from the Sun can disrupt satellite, communication and power systems on Earth.
An Atlas V carrying the observatory left Earth at 1023 local time (1523 GMT) on Thursday.
Once ejected from the rocket's upper-stage, the observatory immediately deployed solar panels to charge its batteries and start operating its systems.