Calculate Airmass

The Calculate Airmass command opens a worksheet dialog where you can calculate an airmass value. The calculation requires the 6 quantities described in the table below. They are entered into the dialog shown here. To calculate the airmass, enter the 6 quantities in the formats like those shown and click the button. For a description of input formats, see the section Data Formats, below.

The Calculate Airmass command opens from the Utilitiesmenu.

Properties for Airmass Calculation
Right Ascension	The right ascension coordinate in units of HMS. The seconds value can have decimal digits. Use the [+] and [x] buttons to add or delete the currently displayed entry.
Declination	The declination coordinate in units of DMS. The seconds value can have decimal digits.
Site Longitude	The longitude of the observing site in units of DMS. The seconds value can have decimal digits. NOTE: The longitude is negative west of the Prime Meridian at Greenwich, England (e.g., the Americas), as per the World Geodetic System specification WGS84.
Site Latitude	The latitude of the observing site in units of DMS. The seconds value can have decimal digits.
UT Date	The UT date of observation in units of YMD.
UT Time	The UT time of observation in units of HMS. The seconds value can have decimal digits.

Data Formats

The 6 input fields each accept multiple values in the form of (Hours, Minutes, Seconds), (Degrees, Minutes, Seconds), or (Year, Month, Day). These are also known as HMS, DMS, and YMD formats, respectively. In using these formats, Mira tolerates a variety of delimiters between the numbers in each field. All the accepted delimiters are listed in the table below. The dialog shown above simply uses spaces between the numbers (listed as (space) in the table).

Field delimiters
HMS	(space) / : – , H h M m S s
DMS	(space) / : – , D d M m S s
YMD	(space) / : – , Y y M m D d (degree) " '

Choose a delimiter that works for you because it is easy to type or makes the entry easy to understand.

Data Formats

Related Topics