# Convert Decimal Degrees/Hours to Components

• 1 Hour = 15 degrees.
• 1 Minute = 15 arcminutes.
• 1 Second = 15 arcseconds.
• Hours can be positive or negative, but always have two digits for the hour.
• Degrees for verticals are usually from -90 to +90, and will have a +/- sign and two digits for the degree
• Degrees for horizontals usually from 0 to 360, will not be negative, will not have a +/- sign, and have three digits for the degrees.
• Longitude is the exception having values from -180 to +180, requiring 4 places for the degree position.
• Hour components are hours, minutes, and seconds, and always designated as h, m, s. E.g. +03h 25m 47.84s.
• Degree componets are degrees, arcminutes, and arcseconds, and always designated as °, ', ". E.g. +18° 43' 36.15"

It is common practice to refer to arcminutes as minutes, and arcseconds as seconds, and the reader must infer the meaning from the context. This may seem absurd and confusing. But the use of minutes and seconds to refer to subdivisions of degrees likely predated their use in time keeping. "Minute" comes from "minute division" (pronounced like "my newt"), and "second" from "2nd division". It is my recommendation that you always refer to arcminutes and arcseconds using their full or abbreviated (arcmin, arcsec) terms, unless depecting them with their symbols (' and ") as part of a full degree readout (e.g 274° 14' 11.04"). Referring to them using ' and " by themselves can possibly confuse the reader as those symbols are also used for feet and inches.

 Right Ascension: Decimal hours, eg. 10.382938 Declination: Decimal degrees, eg. 32.38288 Longitude: Decimal degrees, eg. 249.382988 Longitude 2: Decimal degrees, eg. -85.7636

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