TI-84 Plus: Greenwich Mean Sidereal Time Estimate

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.

Estimating the Boiling Point at Various Elevations

Estimating the Boiling Point at Various Elevations

Equation

We can estimate the boiling point of water, accurate to the nearest tenth (one decimal point), by the formula:

y = 4.299969165*10^-8 * x^2 – 0.0035531324 * x + 100.0049216

Where:

x = elevation in meters

y = boiling point of water in degrees Celsius (°C)

This equation was derived using quadratic regression analysis of 27 sample points, testing points for elevations from -305 m to 6629 m.

If you are working with US units, you can use the following unit conversions:

1 ft = 0.3048 m

Conversion to Celsius:  °C = (°F – 32) * 5/9

Examples

x = -152 m (approx. -498.687664 ft), y ≈ 100.5 °C

x = 4115 m (13500.65617 ft), y ≈ 86.1 °C

x = 6325 m (20751.31234 ft), y ≈ 79.3°

Source:

Glover, Thomas J.  Pocket Ref 4th Edition.  Sequoia Publishing, Inc. Littleton, CO. 2012

Eddie

All original content copyright, © 2011-2018.  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.  Please contact the author if you have questions.