When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Okta - Wikipedia

    en.wikipedia.org/wiki/Okta

    Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast). In addition, in the SYNOP code there is an extra cloud cover indicator '9' indicating that the sky is totally obscured (i.e. hidden from view), usually due to dense fog ...

  3. Clear Sky Chart - Wikipedia

    en.wikipedia.org/wiki/Clear_Sky_Chart

    There are clear sky chart forecasts for over 6100 locations, though the coverage area is limited to Canada, the USA and parts of Mexico and the Caribbean. Locations are typically cities, professional and public observatories, colleges and science centers. However there are also clear sky charts for star parties and backyard observatories.

  4. Skalnate Pleso Atlas of the Heavens - Wikipedia

    en.wikipedia.org/wiki/Skalnate_Pleso_Atlas_of...

    The Atlas Coeli covers both hemispheres with 16 charts. The coordinate system is referred to equinox 1950.0 and the scale is 1° = 0.75 cm. There are six charts of the equatorial regions on a rectangular graticule, covering declinations from +25° to -25°; four charts for each hemisphere with straight, converging hour circles and concentric, equally-spaced declination circles covering ...

  5. Night sky - Wikipedia

    en.wikipedia.org/wiki/Night_sky

    Paranal Observatory nights. [3] The concept of noctcaelador tackles the aesthetic perception of the night sky. [4]Depending on local sky cloud cover, pollution, humidity, and light pollution levels, the stars visible to the unaided naked eye appear as hundreds, thousands or tens of thousands of white pinpoints of light in an otherwise near black sky together with some faint nebulae or clouds ...

  6. Diffuse sky radiation - Wikipedia

    en.wikipedia.org/wiki/Diffuse_sky_radiation

    Hence, the result that when looking at the sky away from the direct incident sunlight, the human eye perceives the sky to be blue. [4] The color perceived is similar to that presented by a monochromatic blue (at wavelength 474–476 nm ) mixed with white light, that is, an unsaturated blue light. [ 5 ]

  7. Bortle scale - Wikipedia

    en.wikipedia.org/wiki/Bortle_scale

    when it is half moon (first/last quarter) in a dark location the sky appears like this, but with the difference that the sky appears dark blue; limiting magnitude with 12.5" reflector is 15; 6 Bright suburban sky 5.1–5.5 18.5–19.25 the zodiacal light is invisible; light pollution makes the sky within 35° of the horizon glow grayish white

  8. Green comet 2023 – live: How to see E3 in sky tonight before ...

    www.aol.com/news/green-comet-2023-live-best...

    Here’s how the sky will look at 4am on the morning of Thursday, 2 February, according to the latest weather forecasts: (Met Office) Watch the green comet drift across US sky

  9. Astronomical seeing - Wikipedia

    en.wikipedia.org/wiki/Astronomical_seeing

    The best systems so far built, such as SPHERE on the ESO VLT and GPI on the Gemini telescope, achieve a Strehl ratio of 90% at a wavelength of 2.2 micrometers, but only within a very small region of the sky at a time. Astronomers can make use of an artificial star by shining a powerful laser to correct for the blurring caused by the atmosphere ...