central meridian

central meridian

The imaginary N–S line bisecting the disk of a planet, satellite, etc., used as a reference.

central meridian

[′sen·trəl mə′rid·ē·ən]
(astronomy)
The meridian of a planet that crosses the center of the visible face of the planet at a given instant.

central meridian

central meridian
The longitudinal line of symmetry of a map projection and, generally, a baseline for referencing the projection to the associated grid coordinate system. As such, grid north and true north are coincident along the central meridian, but at any other point of the projection, grid north and true north diverge as a function of geodetic latitude and longitudinal distance from the central meridian as a result of the convergence of the meridians. Most map projections portray meridian convergence, but one notable exception is the Mercator Projection.
References in periodicals archive ?
On Arzachel's projection, the distances between meridians of longitude along the equator increase away from the central meridian and towards the edges of the map.
Features on Jupiter appear closer to the central meridian than to the limb for 50 minutes before and after transiting.
It's aligned so that vertical grid lines are parallel to the centre of the zone, called the central meridian.
You will need to know angle P (the tilt of the Sun's axis, + if east and - if west); angle B nought ([B.sub.0], the latitude of the centre of the Sun's disk indicating the tilt away or towards the Earth) and angle L nought ([L.sub.0], the longitude of the centre of the disk or of the central meridian).
In the summer of 1997, amidst the devolution of Scotland and Wales and the death of Diana, geographer and award-winning writer, Nicholas Crane, equipped himself with a camouflaged umbrella and embarked on a remarkable walk straight along England's central meridian. A 2,000 metre corridor being his only concession.
"Because I was walking along a route I didn't choose - there's only one central meridian - I came across places I'd never heard of.
The projection seems to be an equidistant Conic with central meridian through Beijing and it includes global longitudes apparently measured in degrees east of the Azores.
See page 48 for information on when the Great Red Spot passes Jupiter's central meridian, and what's in store for the Galilean satellites.
AR1043 N25[degrees]/324[degrees] continued across the disk from the previous month, approaching the central meridian on Feb 1 type Hsx with an area of 30 millionths.
This is the art of recording the longitude of a feature on Jupiter by noting when it appears to cross Jupiter's north-south midline, or central meridian. These timings can be converted to Jovian longitudes by using software or the tables in the annual RASC Observer's Handbook.
The Transverse Mercator projection (a variation of the original, and particularly suitable for tall, thin land shapes) depended upon a suitable centre line -- the Central Meridian. Looking at the options, Davidson's team saw that the Greenwich Meridian was so far east that it would have distorted the mapping on the western part of the country.

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