Hubble Telescope Case Study

Question 0

Describe the problems of the new mirror

Answer 0

• Mirror was flatter at the edges so rays did not focus properly causing fuzzy images.
• error was only 10micrometers was 30x more than 30micrometers

Question 1

Give the designs of the new telescope shape.

Answer 1

• 2.4m in diameter
• Hyperbolic shape
• designed to be used with short wavelength ultraviolet light
• mirror to fit a shape of a tight tolerance of 30nm

Question 2

Describe the new null corrector

Answer 2

• uses interference of light to judge correctness of the surface shape.
• designed by PerkinElmer
• incorrectly assembled

Question 3

What went wrong with the new null corrector?

Answer 3

• lens had to be placed 580mm below reference line to a precision of 10micrometers.
• top of the rod wrongly placed due to laser light being reflected by the chipped anti reflective paint.
• causing the rod to be placed 1.3mm to low

Question 4

What did the other null correctors say?

Answer 4

New null corrector showed that mirror was made to the right shape while the old ones said it had not been.
- because null corrector was newer they went with that

Question 5

What did people do once they realised something was wrong with the telescope?

Answer 5

People worked out the defects from the images and brought up extra parts to add to it.
They also went up to improve some other components, like the computer software.

Question 6

Example of a zero error=

Answer 6

Accurate spacers made by machines calibrated by putting blocks on top of each other, but leave tiny air gaps.

Question 7

Give the summary of the whole case study.

Answer 7

• zero error is a fixed error added or subtracted from the true value.
• cant average zero errors out
• dont trust an instrument because its new
• check everything.