SunriseActivity

Sunrise / Sunset / Moonrise / Moonset Predictor Activity

This activity will display a table of the time of day for the rising and setting of the sun and the moon over a period of seven days.

You may specify a location (longitude and latitudeand time zone offset from GMT) and the starting date that you wish to have a table created for. Alternatively, you can get a table calculated for the week beginning with the current sky.

The latest version (identified as "Version 1, build 3") can be downloaded from TBD.

This version has been tested and confirmed to function on OLPC O/S releases TBD.

Preface

Please add comments on the "discussion" page associated with this article. Where's the source code?
This activity is coded entirely in Python. Therefore, the source for the activity is distributed as part of the .XO file and can (with any tool that understands the compressed format of .XO files, e.g.: WinZip for the PC) be extracted directly from the bundle. Disclaimer: there will be bugs
This is the first "beta" release. It functions and has all the intended initial features buit it still may contain cosmetic bugs. And the algorithms generate times that are precise to the minute but only accurate to about five minutes -- which is pretty poor. Please see the bug tracking page for the list of known bugs or to report a bug.

Introduction

Sunrise was created by a professional programmer and amateur astronomer who likes to vacation in places far removed from his home town and appreciates the opportunity to view the sky from these places. The XO is a wonderful travel accessory for supporting this sort of thing since it is light, compact and frugal of battery power while providing a reasonably large, reasonably high resolution color display.

This Activity is intended to support the star-gazer who has no instrument better than his own eyes. If one uses the rule-of-thumb that the sky is dark enough for astronomy from one hour after sunset to one hour before sunrise, the table this activity generates can be used to plan an observing session. By noting the time of moonrise and moonset, you can additionally plan for lunar observing or predict when the night sky will be maximally dark.

The current version of this activity is "Version 1 (build 3) of 2010.08.13.1600 UT", which can be confirmed by using the "About" feature. See the change log page for revision history.

Before you begin

Be sure your XO has been set to the correct time-zone offset and the correct local time! The astronomical algorithms need to compute GMT (UT) and can't do that if "now" isn't the right time. (This is only an issue if you don't plan to always use "specify date". But it's still an untidy way to operate your computer.)

Installation and set-up

For best results, remove any previous version of Sunrise you may have installed. Re-start X (hit Ctrl-Alt-Backspace). Then, simply follow the usual procedure for downloading and installing an Extra Activity.