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EclipseDroid Tutorial,

Wolfgang Strickling's Android Eclipse Page

EclipseDroid

EclipseDroid is an astronomic app, computing local circumstances for solar eclipses like the contact times, percentual coverage of the sun etc. As these times and values depend on your location, it is useful to get them from your phone with GPS or network localization.
Most interesting are the so called contact times, i. e. the beginning (1st contact, C1) and the end of the eclipse (4th contact, C4), and the start (second contact, C2) and end (3rd contact, C3) of a total or annular eclipse. For partial eclipses, C2 and C3 are not defined, you only obtain C1 and C4 and the maximum of eclipse.

The eclipse algorithms came from Deirdre O'Byrne's Java Script Eclipse Calculator, thanks to Deirdre! BTW: Deirdre's Java Script eclipse calculator will work also on your phone offline!

Main screen

On the main screen (see image left) you see the date of the eclipse, whether it is partial, total or annular. Below this, the actual location (may be GPS or network based, can also choose a custom defined location) is shown. To choose another location, click the Menu button and select "Location". You may select GPS localization, let Google search a place by its address or enter coordinates manually.
If chosen GPS or network localization, EclipseDroid updates your location every 50 meters or 10 seconds and calculates new times if necessary.

Below your coordinates in the second field there are shown the four contact times and the time of mid of eclipse. You see the absolute times and a countdown. Recent events are displayed in gray, future events in green, except those ones in the next five minutes. They are shown in red colour.

In the third field, the next event and its countdown is displayed in a large line. Below this, the current time, the selected timezone and the actual coverage (eclipse magnitude) of the sun. The eclipse magnitude is the amount of the covered solar diameter by the moon.

The main screen updates the countdown timers every second.
Parallel to text output EclipseDroid can speak predefined announcements, you can select or reselect them in the "Settings" menu. Testing the App at the PSE 2011

Below are shown a number of user defined event and action times, like photos or text announcements. These events need a configuration file, the "Actions File", see documentation below.

A click on "simulation" starts an eclipse simulation for training and testing purposes. By default, the simulation starts 65 seconds before C2. You can change this value in the settings menu. You can also start a simulation at a free selectable date and time via the settings menu, selecting "Date Simulation".

The button "local circumstances" at the bottom of the screen starts

the local circumstances form.

This screen displays all local parameters of the eclipse, starting again with the location, showing some more details like the assumed value of deltaT and the altitude above sea level.
The following lines present the contact times, the altitude and azimuth angle of the event. Azimuth 0° is north, 90° is east, 180° south etc..
The position angle to celestial north is given also, as well as the position angle to local zenith, given in an o'clock value. 12 o'clock is upward direction zenith, 3 o'clock right. If C1 has an o'clock position of 3, this means, that the moon will start the eclipse by touching the solar limb exactly from the right side.

Below are several other parameters, like rise and set times and general parameters of the eclipse, like duration, angle of shadow bands (only for total eclipses), the maximal eclipse magnitude, the umbral depth (100% is in th mid of path of totality)

At the bottom of the page you see a table at which time a certain magnitude (coverage of solar diameter) occurs, possibly interesting for photographers. This feature can be deselected via the settings menu in the main screen.

Clicking your phone's menu button enables to copy the text to the clipboard, eg. for saving or sending by email. You can also select to show a NASA map of the eclipse in your webbrowser.

Other menu options are only available in the main screen.
You can select by pressing the menu button:

another eclipse
the location setup
adjust the system clock
simulate the eclipse
change the program settings
edit the actions file
showing a global NASA-Map of the eclipse in your webbrowser
displaying an info text with program version
control the volume of speech output
selecting the language
visiting this webpage
Adding the eclipse to your Android calendar (only in menu of the main form). Respect, that all times are given in the timezone you selected in EclipseDroid, while the times in your calendar depend on the timezone of the android device!

A very important feature is

the system clock adjust screen.

However, this app can not change the system clock itself, as android protects system settings against change by apps.
EclipseDroid stores and applies internally the offset as a correction parameter.

In this screen you can select the offset (i. e. the error) of the system clock and the time zone.
If GPS is active, you can also force a synchronization with GPS time. However, my desire has an average delay of about 1 second. The entered value of GPS delay is added to the displayed GPS time. If you have a mobile network connection, i recommend setting "Automatic" date and time in your phone's "Date & time" menu. It seems to be quite precise.

If you do not have a network connection, you can force a continuous synchronization of EclipseDroid's time to GPS time. For unstable GPS connections, deselect it and load a measured GPS offset into the offset input field.

Setting up the actions file

To show user defined events, announcements or to take snapshots automatically you must select an "actions file" in the settings menu. This is a kind of CSV file with data rows and semicolon separated columns. Once you have selected the file, you can edit it either using your favorite Android text editor or using EclipseDroid's simple text editor in the menu. The file will look similar like this:

Contact;Time;Action;Parameter
C2;-20;Play;/sdcard/20sekunden.mp3
C3;-20;Play;/sdcard/20sekunden.mp3
c2;-55;Flash;300
c2;-45;Photo;45 mins before C2;picture-size=640x480;jpeg-quality=50
c2;-35;Show;Shadow Bands!
c2;-20;Show;Covers off!
c2;-5;Photo;Before Totality
c0;0;Photo;Totality
c3;+35;Show;Shadow Bands!
C3;+20;Show;Covers on!
C3;+120;Show;Game over, serve Champaign
A;12:00:00;show;Noon, let's have lunch
mid;0;Show;Mid of eclipse

Each line consists of minimum four rows, separated by a semicolon. The meaning of those entries are:

First row: The contact. Can be C1, C2, C3, C4 or Mid (=C0), relative to the calculated eclipse events. There is also the possibility to select absolute times, indicated by the letter "A"
Second row: The time. For relative events (C0-C4) it is the time in seconds before (-) or after (+) the contact, absolute timings are given in HH:MM:SS format in UTC.
Do not enter local times!
Third row: The action. Actions can be:
SHOW (displaying a text on the main screen),
PLAY playing an audio file, or
PHOTO, taking a snapshot with the internal camera. Photos are generally made with the maximum resolution and the best JPEG quality (jpeg-quality=100) by default.
FLASH, to release the camera flash, e. g. for launching external cameras like a DSLR. The following number is the flash duration in ms, try something in the range from 100 to 300 ms. My EOS 450D accepts 100 ms.
LAUNCH, launching an external app.
It searches first for the application label (case sensitive), then makes case insensitive search, if not found yet it searches for class name (substring, case insensitive).
fourth row: The parameter.
For SHOW it is the message to be displayed on the screen, otherwise the file to be played or to be launched.
For photos you can select a file for storage. If nothing selected, the file name will be "EclipseDroid". The date and time will be added in every case. Chose the desired photo directory in the settings menu of the main screen!
For photos you can enter a list of additional camera parameters. These settings are a bit tricky, so make extensive tests! Wrong parameters have no effect or can even crash the whole app!
The commands are loaded one by one with the Camera.Parameters.Set method into the camera. Read the android documentation for further details. A sample file of camera settings on my Desire can be downloaded here (from my HTC Desire®). If coordinate acquisition is active (network or GPS), the photos will be geotagged.

For testing the flash mode or camera parameters, try my free app 'Camera Timer'.

Available languages for EclipseDroid: German and English.
If you like to translate EclipseDroid into other languages, please send an email to me ( dr.strickling <at> gmx.de), translation is quite easy!

Download

Download from my website: EclipseDroid.apk (ca. 580 kB), from the Android market or from AndAppStore. System requirements: Android 2.0 or higher
Download source code of eclipse routines here, an example actions file and the camera settings on the Desire as an example for camera settings

This program is currently also available in the Android market.
For manual download you need an Apk_Installer (see QR-Code in the right) or the Astro File Explorer. On your phone you have to allow installation of applications from non-Market sources. Activate in your phone's menu in "Settings", "Applications" the check box "unknown sources", otherwise you will not be able to install my applications!

My other android apps
For lunar eclipses i made an ICAL-calendar file from the lunar eclipses 2011-2100 for import into office Apps or the Google-Calendar:
les.ics (English) or mofis.ics (German)

Software for other computers are developed by:

last Update 2011-07-18
The original URL of this page is http://www.strickling.net/eclipsedroid.htm