Greek Astronomers & Telescopes: Determining Magnitude & Brightness

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    Magnitude System
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Discussion Overview

The discussion revolves around how Greek astronomers might have determined the difference in brightness between stars of different magnitudes using telescopes, despite the historical inaccuracy of their use of telescopes. Participants explore the origins of the magnitude system and its implications for brightness measurement.

Discussion Character

  • Debate/contested
  • Historical
  • Conceptual clarification

Main Points Raised

  • One participant suggests using different size telescopes to equalize the brightness of stars in the eyepiece, questioning if this approach is valid.
  • Another participant challenges this idea by stating that Greek astronomers did not have telescopes and that the magnitude system was established in the late 1800s.
  • A later reply clarifies that while Greek astronomers devised the magnitude system, it was astronomer Herschel who determined the brightness difference between stars of magnitudes 1 and 6 using telescopes.
  • It is noted that the magnitude system was based on apparent brightness determined by the human eye, which has a logarithmic response, leading to a logarithmic brightness system.
  • One participant encourages specificity regarding the term "size" of the telescopes in relation to the initial suggestion.

Areas of Agreement / Disagreement

Participants express disagreement regarding the historical use of telescopes by Greek astronomers and the timeline of the magnitude system's establishment. There is no consensus on the validity of the initial suggestion regarding telescope use.

Contextual Notes

The discussion highlights limitations in historical accuracy regarding the use of telescopes and the development of the magnitude system, as well as the assumptions about the capabilities of Greek astronomers.

skiboka33
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I was asked in a problem to guess how Greek astronomers used 2 telescopes (and no CCDs) to determine that stars with magnitudes 1 and 6 differed in brightness by 100x

My idea was to use different size telescopes to bring the images to the same magnitude in the eyepiec, am i on the right track?
 
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skiboka33 said:
I was asked in a problem to guess how Greek astronomers used 2 telescopes (and no CCDs) to determine that stars with magnitudes 1 and 6 differed in brightness by 100x

My idea was to use different size telescopes to bring the images to the same magnitude in the eyepiec, am i on the right track?
Not even close.
(1) Greek astronomers didn't have telescopes.
(2) The magnitude system of 5 magnitudes being a difference of 100 times in brightness was "decided" on (consensus) in the late 1800's.
 
Sorry, what I meant to say was that Greek astronomers devised the magnitued system and later the astronomer Herschel determined that 2 stars with magnitudes 1 and 6 differend in brightness by 100 times. (My prof gave a hint that he used 2 telescopes to do this)
 
The magnitude system was originally created to be an apparent "brightness" that was determined by eye. Since the eye has a logarithmic response, this eventually translated into the logarithmic brightness system. The magnitudes were assigned long before the system had been formally implemented.

skiboka33 said:
My idea was to use different size telescopes to bring the images to the same magnitude in the eyepiec, am i on the right track?

Yes, though try to be a bit more specific about what you mean by the "size" of the telescopes.
 
Decent explanation can be found here.
 

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