TI-84 Plus: Greenwich Mean Sidereal Time Estimate
Introduction
The program GMST calculates and estimates the Greenwich Mean Sidereal Time for any dates between January 1, 1900 and December 31, 2099.
For any date between 1900 and 2099, the date number is calculated as:
number of days since January 1 + (year - 1900) * 365 + int((1900 - year)/4) + 0.5 + hour/24
Please keep in mind, the formula in this program is from 1978 (see source).
For the hour, a 2400 hour clock format is used. For example, 1 AM = 1, 1 PM = 13.
This program does not take the location of the observer into account.
TI-84 Plus Program: GMST
"2019-03-08 EWS"
Disp "1900-2099"
Input "MONTH: ",M
Input "DAY: ",D
Input "YEAR: ",Y
Input "HOUR: ",H
If fPart(Y/4)=0 and Y≠1900
Then
1→L
Else
0→L
End
If M≥3
Then
int(30.6*M+1.6)+D-35+L→T
Else
int(30.6*M+368.8)+D-400→T
End
T+(Y-1900)*365+iPart((Y-1900)/4)+.5+H/4Z
Z/36525→Z
6°38'45.836"+2400.051262*Z+0°0'0.0929"*Z²→E
24*fPart(E/24)→E
Disp "GMST: ",E>DMS
Example:
Example 1:
January 1, 1978, Midnight (Hour = 0): 6°41'9.836"
Example 2:
March 13, 2011, 7:00 PM (H = 19): 11°23'54.646"
Source:
Jones, Aubrey Mathematical Astronomy With a Pocket Calculator Halsted Press: John Wiley & Sons, New York. 1978. ISBN 0 470 26552 3
Eddie
All original content copyright, © 2011-2019. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.
Introduction
The program GMST calculates and estimates the Greenwich Mean Sidereal Time for any dates between January 1, 1900 and December 31, 2099.
For any date between 1900 and 2099, the date number is calculated as:
number of days since January 1 + (year - 1900) * 365 + int((1900 - year)/4) + 0.5 + hour/24
For the hour, a 2400 hour clock format is used. For example, 1 AM = 1, 1 PM = 13.
This program does not take the location of the observer into account.
TI-84 Plus Program: GMST
"2019-03-08 EWS"
Disp "1900-2099"
Input "MONTH: ",M
Input "DAY: ",D
Input "YEAR: ",Y
Input "HOUR: ",H
If fPart(Y/4)=0 and Y≠1900
Then
1→L
Else
0→L
End
If M≥3
Then
int(30.6*M+1.6)+D-35+L→T
Else
int(30.6*M+368.8)+D-400→T
End
T+(Y-1900)*365+iPart((Y-1900)/4)+.5+H/4Z
Z/36525→Z
6°38'45.836"+2400.051262*Z+0°0'0.0929"*Z²→E
24*fPart(E/24)→E
Disp "GMST: ",E>DMS
Example:
Example 1:
January 1, 1978, Midnight (Hour = 0): 6°41'9.836"
Example 2:
March 13, 2011, 7:00 PM (H = 19): 11°23'54.646"
Source:
Jones, Aubrey Mathematical Astronomy With a Pocket Calculator Halsted Press: John Wiley & Sons, New York. 1978. ISBN 0 470 26552 3
Eddie
All original content copyright, © 2011-2019. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.
