Consider a CCD with a quantum efficiency of 80 percent and a...

Name: Problem 39, Chapter 6: 21st Century Astronomy
Uploaded: 2020-07-09T00:31:55-08:00
Duration: 2 min 10 s
Channel: Matthew Miranda
Description: Consider a CCD with a quantum efficiency of 80 percent and a photographic plate with a quantum efficiency of 1 percent. If an exposure time of 1 hour is required to photograph a celestial object with a given telescope, how much observing time would be saved by substituting a CCD for the photographic plate?

Consider a CCD with a quantum efficiency of 80 percent and a photographic plate with a quantum efficiency of 1 percent. If an exposure time of 1 hour is required to photograph a celestial object with a given telescope, how much observing time would be saved by substituting a CCD for the photographic plate?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Quantum Efficiency

Quantum efficiency is a measure of a detector's ability to convert incoming photons into measurable electrical signals. It is defined as the ratio of the number of electrons generated to the number of incident photons. A higher quantum efficiency means that more photons are effectively captured, reducing the necessary exposure time for a given level of brightness in the resulting image.

Detector Sensitivity

Detector sensitivity refers to how efficiently an imaging device converts light into a signal. This property is critical in astronomical observations where faint celestial objects must be detected. Devices with higher sensitivity, such as modern CCDs, can achieve the same signal quality in a fraction of the time required by less sensitive detectors, thus greatly improving observing efficiency.

Exposure Time Considerations

Exposure time is the duration over which light is collected to form an image. The required exposure time is inversely related to the detector’s efficiency. With more efficient detectors, less time is needed to accumulate enough light to produce a satisfactory image, thereby saving valuable observing time in astronomical observations.

Transcript

Please give Ace some feedback