All Topics  
Square degree

 

 
   Email Print
   Bookmark   Link
 

 

Square degree
 
 
  Topics Square degree Topic Home

A square degree (denoted deg˛) is a non-SI
Si

Si, si, or SI may refer to :...
 unit
Units of measurement

The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day....
 measure of solid angle
Solid angle

The solid angle, O, is the angle in three-dimensional space that an object subtends at a point. It is a measure of how big that object appears to an observer looking from that point....
. Just as degree
Degree (angle)

A degree , usually denoted by ? , is a measurement of plane angle, representing 1/360 of a Turn ; one degree is equivalent to p/180 radians....
s are used to measure parts of a circle, square degrees are used to measure parts of a sphere
Sphere

A sphere is a symmetrical geometrical object. In non-mathematical usage, the term is used to refer either to a round ball or to its two-dimensional surface....
. Analogous to one degree being equal to  radians, a square degree is equal to or about 1/3283 steradian
Steradian

The steradian is the SI unit of solid angle. It is used to describe two-dimensional angular spans in three-dimensional space, analogous to the way in which the radian describes angles in a Plane ....
. The number of square degrees in a whole sphere is or approximately 41,253 deg˛.

For example, observed from the surface of the Earth
Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the World and Wiktionary:Terra.Note that by International Astronomical Union convention, the term "Terra" is used for naming extensive land masses, rather...
, the Moon
Moon

The Moon is Earth's only natural satellite and the List of natural satellites by diameter satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is km, about thirty times the diameter of the Earth....
 has a diameter of approximately 0.5°, so it covers an solid angle of approximately 0.20 deg˛, which is 4.8×10-6 of the total sky sphere.






Discussion
Ask a question about 'Square degree'
Start a new discussion about 'Square degree'
Answer questions from other users
Full Discussion Forum



Encyclopedia


A square degree (denoted deg˛) is a non-SI
Si

Si, si, or SI may refer to :...
 unit
Units of measurement

The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day....
 measure of solid angle
Solid angle

The solid angle, O, is the angle in three-dimensional space that an object subtends at a point. It is a measure of how big that object appears to an observer looking from that point....
. Just as degree
Degree (angle)

A degree , usually denoted by ? , is a measurement of plane angle, representing 1/360 of a Turn ; one degree is equivalent to p/180 radians....
s are used to measure parts of a circle, square degrees are used to measure parts of a sphere
Sphere

A sphere is a symmetrical geometrical object. In non-mathematical usage, the term is used to refer either to a round ball or to its two-dimensional surface....
. Analogous to one degree being equal to  radians, a square degree is equal to or about 1/3283 steradian
Steradian

The steradian is the SI unit of solid angle. It is used to describe two-dimensional angular spans in three-dimensional space, analogous to the way in which the radian describes angles in a Plane ....
. The number of square degrees in a whole sphere is or approximately 41,253 deg˛.

For example, observed from the surface of the Earth
Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the World and Wiktionary:Terra.Note that by International Astronomical Union convention, the term "Terra" is used for naming extensive land masses, rather...
, the Moon
Moon

The Moon is Earth's only natural satellite and the List of natural satellites by diameter satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is km, about thirty times the diameter of the Earth....
 has a diameter of approximately 0.5°, so it covers an solid angle of approximately 0.20 deg˛, which is 4.8×10-6 of the total sky sphere.