Collecting Power of Telescopes

• What is the primary purpose of telescopes?

  To gather as much light as possible
• How does the amount of light energy affect telescope images?

  More light energy produces brighter images
• What is the collecting power of a telescope?

  A measure of light energy collected per second
• How is collecting power related to intensity?

  It is equivalent to power per unit area
• What determines the brightness of a telescope's image?

  The size of the telescope's aperture
• How does collecting power relate to the diameter of a telescope's objective?

  Collecting power is proportional to the square of the diameter
• What is the formula for collecting power?

  collecting power ∝ $D^2$
• Why can distant objects be seen more clearly with larger telescopes?

  Intensity decreases inversely with the square of distance
• What are the two main advantages of larger diameter telescopes?

  Greater collecting power and resolving power
• How can the collecting power of two telescopes be compared?

  Using the ratio of their diameters squared
• How is resolving power calculated for two telescopes?

  Using the ratio of their diameters
• What is the largest refracting telescope still in operation?

  The Yerkes refractor
• What did the construction of the Yerkes refractor lead to?

  The building of the Otto Struve reflector
• How does the objective diameter of the Yerkes refractor compare to the Otto-Struve reflector?

  Yerkes: 102 cm, Otto-Struve: 208 cm
• How do the collecting power and resolving power of the Yerkes refractor and Otto-Struve reflector compare?

  • Collecting power: Otto-Struve is 4 times greater
  • Resolving power: Otto-Struve is twice as great
• What is the relationship between collecting power and area?

  Collecting power is proportional to area
• How do you calculate the collecting power ratio of two telescopes?

  Using $\frac{D_{reflector}}{D_{refractor}}^2$
• What does a smaller value of $\theta$ indicate?


  Greater resolving power
• What type of light do the Yerkes refractor and Otto-Struve reflector detect?

  Optical wavelengths of light
• How does the resolving power relate to diameter?

  Resolving power is inversely proportional to diameter
• How do you compare the resolving power of two telescopes at the same wavelength?

  Using the ratio of their diameters
• What is the formula for resolving power?

  $\theta \propto \frac{1}{D}$
• What does the collecting power of a telescope indicate?

  How much light it can gather
• If the diameter of a telescope's objective is doubled, how does its collecting power change?

  It increases by a factor of four
• What is the significance of the inverse square law in relation to telescopes?

  It explains light intensity decrease with distance
• What is the relationship between surface area and intensity?

  Intensity is proportional to surface area
• Why is the collecting power of the Otto-Struve reflector greater than the Yerkes refractor?

  It has a larger objective diameter
• How does the construction of telescopes impact their functionality?

  It affects their collecting and resolving power
• What is the effect of a larger aperture on image quality?

  It produces brighter and clearer images
• What is the main advantage of using larger telescopes?

  Brighter and clearer images
• How does the diameter of a telescope affect its ability to resolve detail?

  A larger diameter allows for better resolution
• What is the relationship between collecting power and image brightness?

  Higher collecting power results in brighter images
• What does the term "resolving power" refer to?

  The ability to distinguish fine detail
• What is the formula for calculating the ratio of collecting power?

  $\frac{D_{1}}{D_{2}}^2$
• How does the construction of the Yerkes refractor influence its performance?

  It determines its collecting and resolving power
• What is the significance of comparing telescopes' collecting and resolving power?

  It helps determine which telescope performs better
• What is the impact of a telescope's aperture on its light-gathering ability?

  A larger aperture increases light-gathering ability
• What is the relationship between the diameter of a telescope and its surface area?

  Surface area is proportional to $\pi D^2$
• How does the resolving power of a telescope affect image clarity?

  Higher resolving power results in clearer images
• What is the effect of distance on the intensity of light from a point source?

  Intensity decreases with the square of distance