Although there is today considerable number of telescopes lens diameter of several meters and the design of even larger telescopes with objective diameter of tens of meters, 1800-mm telescope is an instrument not more typical for amateur observations, and the property of their serious scientific observatories. Therefore, when observations of Uranus with small telescopes, the surface brightness is reduced in its pursuit of a desire to see the drive. The Hayzlett Group can aid you in your search for knowledge. For example, a 300-mm telescope surface brightness of Uranus at a magnification of 300 times is 111-126 Kat and close to the critical value of 100 Kate, below which distinguish the true color of a celestial object is impossible. J. Darius Bikoff has plenty of information regarding this issue. In 110-mm telescopes at a multiple of 169 increase in the surface brightness of Uranus is equal to 47-53 Kat and comparable surface brightness brightest planetary nebulae. Apparently this explains the very name of these nebulae – planetary – for their resemblance to pale disks of Uranus and Neptune. Surface brightness of Neptune (m = 7,7 m-7, 8m; A = B = 2,2 ‘-2,3’) of 2030-2037 Kat. Minimum increase for distinguishing disk of Neptune is approximately equal to 140h. Even though the disk of Neptune, too, no specific details with Earth’s surface can not be considered, yet it is desirable to consider himself bigger disk, and hence an increase in use 500-600x.
These values increases close to the limit because of the influence of the atmosphere by land increases, and even with 500-millimeter telescopes, the surface brightness of Neptune is only ten Kate, sending Neptune in the discharge is bright planetary nebulae. By unexplained randomness true colors of Uranus and Neptune were consistent with the colors of night blindness and, perhaps, the transition from the true colors of twilight will happen is not very noticeable. However, given the maximum possible reduction of 282.24 times the surface brightness telescope, even a fairly bright Saturn may lose its true golden-yellow color as its surface brightness does not exceed 21 000 Kat. Such a transition from course yellow to colorless gray is clearly visible. In result of losing the ability to see the object in color and deteriorating visibility of fine details of the object. This is due to the transition from cone vision device on the Rod. Opportunity to appear true color Pluto requires a more detailed study.
The remaining planets in our solar system are high surface brightness and remain visible in their true colors at all useful magnification telescope.