Tom.G said:
Adaptive optics is a technique to compensate for the blurring effect of the Earth’s atmosphere, also known as astronomical seeing, which is a big problem faced by all ground-based telescopes. The same turbulence in the atmosphere that causes stars to twinkle to the naked eye results in blurred images of the Universe for large telescopes. Light from stars and galaxies becomes distorted as it passes through our atmosphere, and astronomers must use clever technology to improve image quality artificially.
To achieve this four brilliant lasers are fixed to UT4 that project columns of intense orange light 30 centimetres in diameter into the sky, stimulating sodium atoms high in the atmosphere and creating artificial Laser Guide Stars. Adaptive optics systems use the light from these “stars” to determine the turbulence in the atmosphere and calculate corrections one thousand times per second, commanding the thin, deformable secondary mirror of UT4 to constantly alter its shape, correcting for the distorted light.
I was at a presentation by E2V, the sensor designer and manufacturer where it was pointed out that the adaptive optic system uses an 'artificial star, which is projected by a Sodium Yellow laser on the upper atmosphere. The 'point source' that's produced up there is not distorted significantly as there is just one path from the laser through the atmosphere. The images from the various elements in the multiple reflector are registered together to reduce the effects of the different paths.Tom.G said:New adaptive optics does an amazing job.
VLT (Very Large Telescope) and Hubble Space Telescope are both powerful telescopes used for astronomical observations. VLT is located in Chile and is operated by the European Southern Observatory, while Hubble is a space-based telescope operated by NASA and the European Space Agency.
The images taken by VLT are better than Hubble for several reasons. VLT has a larger mirror, allowing it to capture more light and produce clearer images. VLT is also located on land, which reduces the distortion caused by Earth's atmosphere. Additionally, VLT uses adaptive optics, which corrects for atmospheric turbulence and further improves image quality.
Neptune images from VLT are important because they provide scientists with a better understanding of the planet's atmosphere and its features. The high-quality images allow for more accurate measurements and analysis, which can lead to new discoveries about the planet.
The images are obtained using VLT's advanced technology, including its large mirror and adaptive optics. The telescope tracks the planet's movement and takes multiple images, which are then combined to create a single, detailed image.
The images taken by VLT can provide insights into Neptune's weather patterns, atmospheric composition, and surface features. They can also help us understand how the planet's atmosphere interacts with its moons and other objects in the solar system.