Browse Definitions:
Definition

solid angular measure

Solid angular measure is a quantitative expression for the flare angle at the apex of a cone. It is the three-dimensional analog of plane angular measure .

The unit of solid angular measure in the International System of Units ( SI ) is the steradian (symbolized sr). There are 4 pi (approximately 12.5664) steradians in a complete sphere. A solid angle of 1 sr as defined at a point is such that the area of the subtended portion of a sphere centered at the point is equal to the square of the radius of the sphere.

Sometimes the angular degree (symbolized deg or °) is used to quantify solid angular measure. This is often the case in astronomy, when the angular radius of an apparently disk-shaped celestial object is to be defined. The angular degree is equivalent to 1/360 of a full circle. The Sun and the Moon, as seen from the Earth, both subtend solid angles represented by cones whose apexes are slanted approximately 0.25 degree to the cone axis. Thus, the Sun and the Moon can be said to have solid angular radii of about 0.25 degree.

Compare plane angular measure . Also see steradian , angular degree , SI , and Table of Physical Units .

This was last updated in September 2005

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • phishing

    Phishing is a form of fraud in which an attacker masquerades as a reputable entity or person in email or other communication ...

  • vulnerability disclosure

    Vulnerability disclosure is the practice of publishing information about a computer security problem, and a type of policy that ...

  • incident response

    Incident response is an organized approach to addressing and managing the aftermath of a security breach or cyberattack, also ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

  • flash memory

    Flash memory, also known as flash storage, is a type of nonvolatile memory that erases data in units called blocks.

  • NAND flash memory

    NAND flash memory is a type of nonvolatile storage technology that does not require power to retain data.

  • NOR flash memory

    NOR flash memory is one of two types of nonvolatile storage technologies.

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close