IIA scientists propose new metric which can help quantify image quality of the Sun taken from ground-based telescopes

According to the Ministry of Science and Technology, dynamic occasions like flares, prominences, and coronal mass ejections going down on the floor of the Sun have made the photo voltaic physique the focus of curiosity of astronomers.
| Photo Credit: representational image

Scientists from the Indian Institute of Astrophysics (IIA) have proposed a new metric, which can help quantify image quality of the Sun taken from ground-based telescopes.

According to the Ministry of Science and Technology, dynamic occasions like flares, prominences, and coronal mass ejections going down on the floor of the Sun have made the photo voltaic physique the focus of curiosity of astronomers.

“Being the closest star, it can be studied in great detail, and properties of other stars may be extrapolated by the understanding of the Sun. To resolve even the smallest features in greater detail, large telescopes are built,” stated the Ministry of Science and Technology.

Scientists from IIA have proposed to make use of a novel metric referred to as the root imply sq. granulation distinction to quantify the image quality of ground-based photo voltaic telescopes.
| Photo Credit:
file picture

However there’s a main drawback when the telescopes are on the floor. “The light from the Sun passes through the Earth’s atmosphere, which is not a homogenous medium. There are random temperature fluctuations that lead to refractive index fluctuations. This causes the light to bend randomly and can be observed as the variation of intensity (scintillation/twinkling) and position of the image on the detector. One way to overcome this is to use an adaptive optics (AO) system to measure and correct for the distortions introduced by the atmosphere in real time,” the Ministry stated.

It additional added that the quality of the pictures obtained from ground-based telescopes can’t be quantified with the Strehl ratio or different metrics used immediately for nighttime astronomical telescopes.

To overcome this, scientists from IIA have proposed to make use of a novel metric referred to as the root imply sq. (rms) granulation distinction to quantify the image quality of ground-based photo voltaic telescopes.

Using theories that can be used to elucidate the turbulence launched by the ambiance, scientists Saraswathi Kalyani Subramanian and Sridharan Rengaswamy carried out simulations of how an image would look when there is no such thing as a atmospheric turbulence (ultimate case) and in comparison with the image when there may be an environment (perturbed image) and when AO correction is finished.

“Comparing the results of the idealistic simulations to practical systems, they computed an efficiency factor deriving an efficiency of about 40 to 55% for Strehl ratio and about 50% as a lower bound for contrast. Their results will be useful in characterising the performance of any solar telescope and associated AO system,” the Ministry stated.