Aditya-L1 has been successfully launched from the Satish Dhawan Space Research Centre in Sriharikota on Saturday. The first Sun mission from India carried by the Polar Satellite Launch Vehicle (PSLV)-C57 rocket is equipped with seven payloads. Among these, the Visible Line Emission Coronagraph (VELC) is the primary payload that Aditya-L1 will use to focus on the Sun’s Corona. (Follow LIVE updates on Aditya-L1 launch here)
Annapurni Subramaniam, Director of the Indian Institute of Astrophysics Bangalore, which delivered VELC to ISRO, said that this payload has been designed to create a ‘total solar eclipse’ all the time once Aditya-L1 is placed in L1 (Lagrangian Point 1).
“We have delivered the main instrument for this mission, which is the Visible Line Emission Coronagraph (VELC). It will create a total solar eclipse continuously since it will be positioned at L1, providing an unobstructed view of the Sun. It will constantly observe the Sun in eclipse. This will be the first mission to examine the innermost part of the Corona,” news agency ANI quoted Annapurni Subramaniam as saying.
Aditya-L1 will be placed in a halo orbit around Lagrangian Point 1 (L1), which is 1.5 million kilometers from Earth in the direction of the Sun.
What will VELC find out in this Solar mission?
-VELC aims to collect data to understand how the temperature of the solar corona can reach about a million degrees while the Sun’s surface remains at just over 6000 degrees Celsius. It does this by continuously observing the corona, starting from its lower boundary and moving upwards, while filtering out the bright light from the solar disc.
-The payload will send 1,440 images per day to the ground station for analysis once it reaches its intended orbit. VELC has the capability to capture images of the solar corona closer to the Sun’s disc than any other solar space observatory.
-VELC has a mechanism to occult (block) the solar disc to separate and discard the light from the Sun’s disk. This allows it to observe the Sun as if it were a solar eclipse, enabling the study of the corona and its characteristics, including its origin and the source of coronal mass ejections.
-The Indian Institute of Astrophysics (IIA) is actively involved in the calibration and utilisation of data from VELC and other payloads on Aditya-L1. They aim to address fundamental questions about solar astrophysics and its impact on daily life.
-VELC’s ability to capture close-up images of the solar corona is attributed to its extremely accurately polished primary mirror, which was crafted by ISRO’s Laboratory for Electro Optics Systems (LEOS). This precision reduces light scatter within VELC.