Meridian width

Under the Meridian width is meant the determination of the latitude of the observation of a bright celestial body , which especially in the Meridian culminates, ie reaches its peak.

The sun is at 12 noon true local time (WOZ) in the upper meridian (here in the south). Therefore, the latitude determined from this is also called midday latitude . An exact latitude determination is also possible with other stars in the meridian passage .

At midnight (00.00 a.m. WOZ) the sun is in the lower meridian (only visible in polar regions). The latitude determined here is called the midnight latitude , also for observing other stars. The observation of the sun in the lower meridian is only possible towards the poles of the polar circles in north or south summer. One then speaks of the midnight sun .

The width results from a simple addition of angles : measured zenith distance (90 ° - elevation angle) plus declination of the star.

See also

• Determination of latitude
• Astronomical_navigation # determination_of_latitude

Web links

• Determination of the midday width on www.astrosail.de. Retrieved October 19, 2010 .