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  2. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    Right: a few minutes later the Sun is on the local meridian again. A solar day is complete. Solar time is measured by the apparent diurnal motion of the Sun. Local noon in apparent solar time is the moment when the Sun is exactly due south or north (depending on the observer's latitude and the season). A mean solar day (what we normally measure ...

  3. Solar Dynamics Observatory - Wikipedia

    en.wikipedia.org/wiki/Solar_Dynamics_Observatory

    HMI takes high-resolution measurements of the longitudinal and vector magnetic field by viewing the entirety of the Sun's disk, with emphasis on various concentrations of metals in the Sun; specifically it passes the light (the variety of usable frequencies of which are centered on the solar spectrum's 617.3-nm Fraunhofer line) through five ...

  4. Solar time - Wikipedia

    en.wikipedia.org/wiki/Solar_time

    On a prograde planet like the Earth, the sidereal day is shorter than the solar day. At time 1, the Sun and a certain distant star are both overhead. At time 2, the planet has rotated 360° and the distant star is overhead again (1→2 = one sidereal day). But it is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). More simply, 1→2 is a complete ...

  5. GOES-16 - Wikipedia

    en.wikipedia.org/wiki/GOES-16

    GOES-16, formerly known as GOES-R before reaching geostationary orbit, is the first of the GOES-R series of Geostationary Operational Environmental Satellites (GOES) operated by NASA and the National Oceanic and Atmospheric Administration (NOAA).

  6. Sun chart - Wikipedia

    en.wikipedia.org/wiki/Sun_chart

    Most sun charts plot azimuth versus altitude throughout the days of the winter solstice and summer solstice, as well as a number of intervening days.Since the apparent movement of the Sun as viewed from Earth is nearly symmetrical about the solstice, plotting dates for one half of the year gives a good approximation for the rest of the year.

  7. Sunlight - Wikipedia

    en.wikipedia.org/wiki/Sunlight

    The spectrum of the Sun's solar radiation can be compared to that of a black body [11] [12] with a temperature of about 5,800 K [13] (see graph). The Sun emits EM radiation across most of the electromagnetic spectrum.

  8. Solar rotation - Wikipedia

    en.wikipedia.org/wiki/Solar_rotation

    At the equator, the solar rotation period is 24.47 days. This is called the sidereal rotation period, and should not be confused with the synodic rotation period of 26.24 days, which is the time for a fixed feature on the Sun to rotate to the same apparent position as viewed from Earth (the Earth's orbital rotation is in the same direction as the Sun's rotation).

  9. Atmospheric refraction - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_refraction

    Diagram showing displacement of the Sun's image at sunrise and sunset Comparison of inferior and superior mirages due to differing air refractive indices, n. Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. [1]