Friday, May 23, 2014

PCalc and HP50g: Distance of a Star by Parallax

Source: Astronomy 801: Planets, Stars, and the Universe - Penn State University
https://www.e-education.psu.edu/astro801/

PCalc Program: Distance of a Star by Parallax (Degrees Mode)
5/19/2014

D = approximate distance from Earth to the star
P = angle in arc seconds (1/3600 of the degree)

D = 1/ (tan(P/3600) * 63239.7263452)

1 light year = 63239.7263452 AU

(AU: distance from Earth to the Sun)

Input:
X: angle in arc seconds

Output:
X: distance in light year

Program:
Decimal Mode
Degrees Mode
Divide X By 3600
Tangent X
Multiply X By 63239.7263452
Invert X

Example:
Input:
X: 0.54 arc second

Output:
X: 6.0400619278 light years

HP 50g: Distance of a Star by Parallax

The commands PUSH and POP are used to preserve and recall settings. PUSH stores the settings while POP recalls stored settings. This allows the program to make necessary changes to program modes during execution with permanently affecting the settings for the user.

Input:
1: angle in arc seconds

Output:
1: distance to star in light years

Program PARALLAX
<< PUSH DEG 3600 / TAN
63239.7263452 * INV POP >>

This blog is property of Edward Shore. 2014