ZERO SHADOW DAY - PRIVACY POLICY

Last updated: 27 July 2026


IN SHORT

Zero Shadow Day collects nothing about you. There are no accounts, no
advertising, no analytics and no tracking in the app. Your location, if you
choose to share it, is used on your device to work out when the Sun passes
overhead where you are. It is never sent to me and never stored anywhere I can
see it.


WHAT THIS COVERS

This policy covers the Zero Shadow Day app for iPhone and iPad (bundle id
com.alokm.zsd) and for Android (package com.alokm.zsd), both published by Alok
Mandavgane, and the browser version of the app. The app is made for the Public
Outreach and Education Committee of the Astronomical Society of India.


WHAT THE APP KEEPS ON YOUR DEVICE

The app remembers two things, using the ordinary app storage your operating
system provides (UserDefaults on iOS, SharedPreferences on Android):

  - the place you have chosen: its latitude, longitude, name and time zone
  - the language you have chosen for the app's own text

Both stay on your device. Neither is sent anywhere. Both are removed when you
uninstall the app, or when you clear the app's data.


LOCATION

Sharing your location is optional. The app works fully without it: decline the
permission and you are asked to pick a city instead, and every feature works
from that city.

  - On iPhone and iPad the permission is requested only when you tap the
    location button in the top bar.
  - On Android the app asks for approximate location (ACCESS_COARSE_LOCATION)
    the first time it runs, and you may refuse.

If you do share it, your coordinates are used in three ways:

  1. On your device, to calculate your zero shadow days, local noon and shadow
     lengths. All of this arithmetic happens on the device; nothing about it
     leaves it.
  2. To ask your operating system's geocoding service to turn the coordinates
     into a place name - Apple's on iPhone and iPad, Google's on Android. That
     request goes to Apple or Google, not to me, and is handled under their
     privacy policies.
  3. To centre the map on you, which means the area you are looking at is
     requested from Google's map servers as described below.

I never receive your location, and no copy of it exists outside your device and
those services.


MAPS

The zero shadow day finder uses the Google Maps SDK. When you open it, the map
data for the area shown is fetched from Google, and Google collects information
about that use under its own privacy policy:

  https://policies.google.com/privacy

I have no access to anything Google collects this way.


WHAT THE APP DOES NOT DO

  - No account, sign-in, email address or name is ever asked for.
  - No advertising, and no advertising identifier is read.
  - No analytics or crash-reporting service of any kind is built into the
    mobile apps.
  - Nothing you do is tracked across other apps or websites.
  - Nothing is sold or shared, because nothing is collected.

One exception worth stating plainly: if you have chosen in your device settings
to share analytics and crash reports with app developers, Apple and Google may
pass me aggregated, anonymised reports about crashes and general usage. That is
their mechanism, not the app's, it can be switched off in your device settings,
and the reports do not identify you.


THE BROWSER VERSION

The web version of Zero Shadow Day is different in one respect: the page uses
Google Analytics to count page views, which involves cookies and lets Google
estimate an approximate location from your IP address. Nothing you enter in the
app is sent to it - only which view you opened. It is covered by Google's
privacy policy above, and Google's opt-out is at:

  https://tools.google.com/dlpage/gaoptout

The apps for iPhone, iPad and Android contain no analytics at all.


CHILDREN

The app is suitable for all ages and collects no personal information from
anyone, children included.


YOUR DATA, AND REMOVING IT

Because nothing about you is collected or held by me, there is no personal data
of yours for me to show you, correct or delete. The place and language the app
remembers are on your own device: uninstalling the app, or clearing its data in
your device settings, removes them. You can withdraw location access at any
time in your device's privacy settings.


CHANGES TO THIS POLICY

If this policy changes, the new version will appear at this address with a new
date at the top. Material changes will also be noted in the app's release
notes.


CONTACT

Questions about this policy, or about anything the app does with data:

  Alok Mandavgane
  alok@alokm.com