Post Reply 
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
computing the time of the seasons with the HP Prime
13-03-2016, 07:35 PM
Post: #1
computing the time of the seasons with the HP Prime
This HP Prime program uses several of the routines already provided in this forum to compute the time of the seasons; spring equinox, summer solstice, fall equinox and winter solstice.

The user can edit the program and provide a calendar year of interest. The software computes the calendar date and Universal Coordinated Time (UTC) of each celestial event. Here are the program results for 2016. The UTC is typically within 10 minutes of the time computed with a precision solar ephemeris. The local civil time of an event at a particular geographic location is a function of the time zone and the status of daylight savings time (DST) at that location.

time of the equinoxes and solstices


calendar date Mar 20, 2016

UTC time 4 hr 20 min 53.088 sec


calendar date Jun 20, 2016

UTC time 22 hr 25 min 28.704 sec


calendar date Sep 22, 2016

UTC time 14 hr 11 min 14.496 sec


calendar date Dec 21, 2016

UTC time 10 hr 34 min 24.384 sec

This program uses several routines slightly modified for this application. In the zip collection, they are brent_equsol, sun_equsol and esfunc. A PDF document explaining the basic algorithm is also provided.

Attached File(s)
.zip (Size: 164.59 KB / Downloads: 5)
Find all posts by this user
Quote this message in a reply
Post Reply 

Messages In This Thread
computing the time of the seasons with the HP Prime - cdeaglejr - 13-03-2016 07:35 PM

Forum Jump:

User(s) browsing this thread: 1 Guest(s)