Sriharikota (AP) | ISRO is all set to launch India's maiden solar mission, Aditya L1, from the spaceport here on Saturday, the countdown for which was on.

Aditya-L1 is the first space-based observatory class to study the Sun and is being fired using ISRO's reliable Polar Satellite Launch Vehicle (PSLV) from here at 11.50 am.

The spacecraft, after traveling about 1.5 million km from the Earth over 125 days, is expected to be placed in a Halo orbit around the Lagrangian point L1 which is considered closest to the Sun.

The major objectives of the mission include understanding the Coronal Heating and Solar Wind Acceleration, the initiation of Coronal Mass Ejection, and near-earth space weather and the solar wind distribution.

The Aditya-L1 mission carries seven scientific payloads to carry out the study.

The Sun expedition comes close on the heels of ISRO's successful moon mission, Chandrayaan 3.

The 23.40 hour countdown for today's launch commenced at 12.10 pm on Friday.