Context:
Recently, scientists developed a new methodology, called Equal Contrast Technique (ECT), to analyse Sun images in white light, which can help prevent temporal and latitudinal variations in observations related to instrument and sky conditions.
![](https://sp-ao.shortpixel.ai/client/to_webp,q_glossy,ret_img,w_452,h_219/https://www.legacyias.com/wp-content/uploads/2023/08/equal_contrast-Legacy-ias.png)
Relevance:
GS III: Science and Technology
Dimensions of the Article:
- Key Points
- Significance
- Magnetogram
Key Points:
- The Sun exhibits numerous regions of weak magnetic fields that change over time.
- Magnetograms and Ca-K line images are used to study these regions due to a strong correlation between magnetic field and Ca-K line intensity.
- Magneto-grams have limited availability and instrument characteristics change over time.
- Ca-K line images have long-term availability at Kodaikanal Observatory (KO) and other observatories like Mount Wilson Observatory (MWO).
- Researchers used Kodaikanal data to establish a strong correlation between derived plage area (bright region in the sun’s chromosphere) from Ca-K images and sunspot numbers. This correlation is evident even on a daily basis over about 100 years.
Significance:
- Accurate analysis of historical Ca-K image time series provides reliable insight into sun variations and their impact on Earth’s climate.
- Understanding sun dynamics, solar cycle variations, convection zone dynamo processes, and resulting long-term climatic variations on Earth is facilitated.
Magnetogram
- A magnetogram is an image captured by an instrument that is capable of detecting and depicting the strength and distribution of magnetic fields on the Sun’s surface.
- In a magnetogram, different shades of gray are used to represent varying levels of magnetic strength.
- The absence of a magnetic field is often represented by a neutral shade of gray.
- Black and white areas on a magnetogram indicate regions where the magnetic field is particularly strong or weak, respectively.
- This visualization technique helps scientists study the complex magnetic activity and patterns on the Sun, which play a crucial role in various solar phenomena and processes.
-Source: The Hindu, PIB