Solid Angle

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The following units are included in this section:

 

ID

Unit

Definition

Wikipedia page and other notes

1

steradian (sr)

-

https://en.wikipedia.org/wiki/Steradian

2

millisteradian (msr)

10-3 sr

https://en.wikipedia.org/wiki/Steradian

Page refers to steradian, not millisteradian

3

sq. degree (sq °)

(π/180)2 sr

https://en.wikipedia.org/wiki/Square_degree

4

sq. gradian (sq grad, sq gon)

(π/200)2 sr

https://en.wikipedia.org/wiki/Gradian

Page refers to gradian, not square gradian

5

spat, sphere (sp)

4π sr

https://en.wikipedia.org/wiki/Spat_(unit)

6

hemisphere

2π sr

 

7

spher. right angle

(π/2) sr

 

8

sq. arcmin (sq ′)

(π/10,800)2 sr

https://en.wikipedia.org/wiki/Solid_angle#Square_minute

9

sq. arcsec (sq ″)

(π/648,000)2 sr

https://en.wikipedia.org/wiki/Solid_angle#Square_second

10

sq. milliradian (sq mrad)

10-6 sr

 

 

All the above definitions of the various units are EXACT.

Note: In the above, a period (.) is used to indicate the decimal place and a comma (,) is used to separate groups of thousands.

 

Type of conversion relationship: DIRECTLY PROPORTIONAL (y=ax)

Example conversion diagram (see two units in bold above):

Solid Angle