Visible Emission Line Coronagraph (VELC)

Recently, scientists from the Indian Institute of Astrophysics (IIA), in collaboration with NASA, successfully estimated crucial parameters of a Coronal Mass Ejection (CME) using data from the Visible Emission Line Coronagraph (VELC).
The VELC is one of the key scientific payloads aboard Aditya-L1, India’s first dedicated solar mission.

About the Visible Emission Line Coronagraph (VELC)

The Visible Emission Line Coronagraph is the primary payload of the Aditya-L1 Mission, designed for continuous and close observation of the Sun.
Aditya-L1 orbits around the L1 Lagrange point, nearly 1.5 million km away from Earth, providing an uninterrupted view of the Sun.

Key Features of the Visible Emission Line Coronagraph

1. Internally Occulted Solar Coronagraph

VELC is an internally occulted coronagraph, enabling it to block the bright solar disk and capture detailed images of the faint solar corona.

2. Multi-Capability Payload

It is capable of simultaneous imaging, spectroscopy, and spectro-polarimetry near the solar limb, making it a highly advanced solar observation instrument.

3. Advanced Optical Components

The instrument comprises:

• A coronagraph

• A spectrograph

• A polarimetry module

• High-precision detectors

• Additional auxiliary optics

4. Built by Indian Institute of Astrophysics

VELC was developed by the Indian Institute of Astrophysics (IIA) at its CREST campus located at Hosakote, Karnataka.

Objectives of the Visible Emission Line Coronagraph

1. Observation of the Solar Corona

VELC is designed to study the solar corona, the outermost and extremely hot layer of the Sun's atmosphere.

2. Closest Imaging Capability

It can image the corona up to 1.05 solar radii, which is the closest any coronagraph payload has achieved so far.

3. Analysis of Coronal Properties

VELC will help determine:

• Temperature of coronal plasma

• Velocity of solar material

• Density of coronal particles

4. Study of CMEs and Solar Wind

The payload will play a crucial role in understanding Coronal Mass Ejections (CMEs) and the solar wind, both of which significantly influence space weather.