Angular Resolution: Best Possible Observing Distance for Stars

[intervoxel]

Supposing a perfect optical instrument, what is the best angular resolution possible when observing distant stars?

 

[Filip Larsen]

You may want to read up on the concept of "diffraction limited telescope".

 

[Drakkith]

Supposing a perfect optical instrument, what is the best angular resolution possible when observing distant stars?

The depends almost entirely upon the diameter of the aperture and the wavelength you are asking about.

http://en.wikipedia.org/wiki/Airy_disk

 

[zhermes]

The previous answers are entirely correct, but also note that ground-based telescopes (as apposed to space-based) are often more limited by 'seeing' than the diffraction limit. Atmospheric Seeing is deterioration of the signal based on variations (turbulence, etc) in the atmosphere.

 

[pmacias]

The best angular resolution possible when observing distant stars is determined by the diffraction limit, which is a fundamental limitation imposed by the wave nature of light. This limit states that the smallest resolvable angle, or angular resolution, is directly proportional to the wavelength of light and inversely proportional to the diameter of the optical instrument's aperture.

In other words, the longer the wavelength of light and the smaller the aperture, the lower the angular resolution. For example, using visible light with a wavelength of 500 nanometers and a telescope with an aperture of 1 meter, the best possible angular resolution would be approximately 0.00002 degrees.

However, this is assuming a perfect optical instrument with no atmospheric disturbances. In reality, factors such as atmospheric turbulence and imperfections in the telescope's optics can significantly degrade the angular resolution. Therefore, the best angular resolution achievable in practice may be slightly lower than the theoretical limit.

In conclusion, the best possible angular resolution for observing distant stars is limited by the diffraction limit and is dependent on the wavelength of light and the aperture of the optical instrument. With advancements in technology and techniques, scientists continue to push the boundaries of angular resolution and improve our understanding of the universe.