Thirty Meter Telescope - GS questions based on daily current affairs

1)   What is astronomical or atmospheric seeing in relation to observatories?

a. High frequency temperature fluctuations of the atmosphere
b. Reduced visibility due to cloud cover
c. Reduced visibility due to solar flares
d. The capacity of an observatory to see the moon as a reference
Answer  Explanation 

ANSWER: High frequency temperature fluctuations of the atmosphere

Explanation:

  • Seeing is high frequency temperature fluctuations of the atmosphere, and the mixing of air parcels of different temperatures/densities.
  • This behaviour of the atmosphere is seen at the eyepiece as a blurred, moving, or scintillating image.
  • There are roughly 3 main areas where Atmospheric turbulence occurs. Near ground seeing (0 – 100 metres or so.) central troposphere (100m – 2km), and High troposphere (6-12km.) Each area exhibits different characteristics.
  • Hanle in Ladakh has been identified as one of the potential alternate sites for the Thirty Meter Telescope (TMT).
  • Hanle site has lower seeing values of 0.9-1.2 arc sec as compared to the alternate sites in Chile and Canary Islands of Spain (La Palma) which have seeing values of 0.55 arc sec. Thus, scientifically, Hanle has less advantageous characteristics for hosting a mega telescope like the TMT in comparison to the other alternate sites.
2)   Which is the most important parameter to decide the location of hosting the Thirty Metre Telescope?

a. Seeing
b. Cost of the project
c. Environmental concern
d. Temperature of the surrounding areas
Answer  Explanation 

ANSWER: Seeing

Explanation:

  • Key scientific parameter, viz. ‘Atmospheric turbulence or Seeing measured in arc-second’ is assessed while determining the location of telescopes.
  • An observer, be they at a mountain top observatory, or in their own back yard must, at all times contend with the Earth’s atmosphere. It is a notoriously unpredictable and limiting factor in obtaining fine views of the Planets, and close binary stars.
  • Hanle in Ladakh has been identified as one of the potential alternate sites for the Thirty Meter Telescope (TMT). The original site for TMT was Mauna Kea in Hawaii in the United States of America.

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