sDate, sTime are the UT date and time
strings to convert to Julian Date.CalcHJD
The CalcHJD function calculates the Heliocentric Julian Date using the date and time plus the right ascension and declination of the object. The date and time may be expressed as two strings for date and time or as a merged ISO 8601 date/time string. The Heliocentric Julian Date is refeferenced to the Sun's location, hence is independent of Earth's motion and the object coordinates. Use CalcJC to calculate the "normal", or Geocentric Julian Date.
nJD = CalcHJD( sDate, sTime, sRA, sDec )
nJD = CalcHJD( sDateTime, sRA, sDec )
sDate, sTime are the UT date and time
strings to convert to Julian Date.
sDateTime
is the standard (ISO 8601) merged UT date/time string separated
with the letter T, like '2024-12-23T04:17:49'.
sRA and
sDec are the right ascension and
declination of the object.
nJD is the
Julian Date (e.g., 2441552.645325).
The following inverse operations convert a Julian Date number to its number and string components:
Use
ParseJD to split the
Julian Date number into 3 numbers for the date and 3 numbers for
the time.
Use
JDtoDateTime to
split the Julian Date number into two strings for date and
time.
To
calculate the "normal", or geocentric Julian Date, use CalcJD.
The following script converts UT date and time, right ascension, and declination to Heliocentric Julian Date:
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-- 17 June 1999 UT |
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-- 01:01:59.0 UT |
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-- RA: 18h 42m 43.42s |
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-- Dec: 63 degrees 35' 06.1" |
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-- calculate the HJD |
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-- Result: JD = 2451346.54326 |
The following script calculates the Heliocentric Julian Date using the ISO 8601 version of date and time:
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-- 17 June 1999 at 01:01:59.0 UT |
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-- RA: 18h 42m 43.42s |
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-- Dec: 63 degrees 35' 06.1" |
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-- calculate the HJD |
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-- Result: JD = 2451346.54326 |
Mira Pro x64 Script User's Guide, v.8.77 Copyright Ⓒ 2024
Mirametrics, Inc. All Rights Reserved.