Ishigaki Star Guide Privacy Policy

DRAFT — not yet reviewed by Nobunari Arakaki (created 2026-09-08 by Claude).
The app’s final name is undecided; Ishigaki Star Guide is a placeholder for a global find-and-replace.

Ishigaki Star Guide — Privacy Policy

Last updated: 2026-09-08 (insert the release date)
Effective: 2026-09-08

Hoshihaku, Inc. (“we”, “us”) respects the privacy of everyone who uses the mobile application
Ishigaki Star Guide (the “App”). This policy explains what the App does and does not do with information.

Summary

The App collects no personally identifiable information whatsoever.
No account is required. There is no sign-in.
There are no advertisements, no analytics SDKs, and no tracking of any kind.
The App is free, with no in-app purchases.
Settings and your constellation collection are stored only on your device. They are never sent to us.
We operate no server for this App, so we have no means of receiving your data.
The only data that leaves your device is your approximate latitude and longitude, sent solely to
fetch a weather forecast (see Section 2).

1. Information we do not collect

The App does not collect, store, or transmit any of the following.

Item	Handling
Name, email address, phone number, postal address	Not collected (there are no such input fields)
Account credentials or passwords	Not collected (there is no account system)
Device identifiers (IDFA, Advertising ID, device ID)	Not collected
Contacts, photos, calendar, microphone, files	Not accessed
Usage history, interaction logs, crash reports	Not collected (no analytics SDK is embedded)
Purchase or payment information	Not collected (there are no purchases)

2. Location

2-1. Why the App uses it

The App is a sky map. What is visible in the sky depends entirely on the observer’s latitude and
longitude, so the App uses your coordinates for two purposes:

Astronomical calculation on your device — altitude and azimuth of stars, constellations, the Moon
and planets; moonrise and moonset; the best viewing time for an object. All of this is computed
locally on your device and never leaves it.
Fetching the local weather forecast, used to compute the “Sky Score” (how good tonight’s sky is).

2-2. What is sent off the device

To fetch the forecast, the App sends only your latitude and longitude over HTTPS to Open-Meteo,
a free and open-source weather API service.

Endpoint: https://api.open-meteo.com/ (operated by Open-Meteo, Austria)
Sent: decimal latitude and longitude, plus the names of the weather variables requested
Not sent: your name, any device identifier, any account information, or anything else that
could identify you
We do not receive or store these coordinates; the request does not pass through any server of ours
Open-Meteo’s own handling is governed by their terms: https://open-meteo.com/en/terms

Because coordinates can indicate your approximate whereabouts, we treat them as location data. They are
used for app functionality only, are never linked to your identity, and are never used for tracking,
advertising, or profiling.

2-3. If you decline

Nearly every feature works without location permission. If you decline, the App uses fixed coordinates
for the Hirakubo Peninsula of Ishigaki Island, Japan (24.6111° N, 124.3111° E) as the observing site.

You may revoke location permission at any time in your device settings.

3. Camera

The App’s “AR mode” uses the rear camera for one purpose only: to display the live view behind the star
map so that constellations appear to overlay the real sky.

The App does not take photographs or video, does not save any image, and does not transmit anything.
The camera feed is displayed on screen and discarded immediately; nothing is retained.
The camera is stopped whenever AR mode is off and whenever the App is closed or in the background
(the camera component is unmounted, not merely paused).
Declining camera permission leaves every sky-map feature fully usable; only the live background is absent.

You may revoke camera permission at any time in your device settings.

4. Information stored on your device

The following is stored in the App’s private storage area (React Native AsyncStorage).
Neither we nor any third party can read it.

Storage key	Contents
`@hoshizora/settings/v1`	Display language, layer toggles, magnitude limit, vertical flip, compass calibration
`@hoshizora/constellationCatches/v1`	Your constellation collection (IAU abbreviation and capture timestamp)
`@hoshizora/challengeIntroSeen/v1`	Whether you have already read the challenge-mode introduction

None of this is transmitted, backed up to us, or used for advertising.
How to delete it: uninstalling the App removes all of it permanently.

5. Third-party services the App contacts

Service	Purpose	What is sent
Open-Meteo (weather API)	Weather forecast for the Sky Score	Latitude and longitude only
Expo (EAS Update)	Delivery of app updates	Technical information required to serve an update, such as app version and platform. No personal information is sent
Apple Maps (iOS only)	Rendering the light-pollution map	The map viewport, through the operating system’s standard map component
Google Maps	Directions to an observing spot	Only when you tap “Open in Maps”, the coordinates of that spot are passed to the external browser or Maps app

We pass no information that identifies you to any of these services. Each provider’s own privacy policy
governs its handling of the request.

The spoken guide that reads object descriptions aloud uses your device’s built-in text-to-speech.
No text or audio is sent to any server of ours.

6. No sharing, no advertising, no tracking

We do not sell, share, or disclose user information to third parties — we hold none.
The App displays no advertisements and contains no advertising SDK.
The App performs no tracking as defined by Apple’s App Tracking Transparency framework.
No analytics tool (Google Analytics, Firebase Analytics, or similar) is embedded.

7. Children

The App is suitable for all ages and is designed to be enjoyed by families observing the night sky together.

Because no personal information is collected, no situation arises that would require verifiable
parental consent.
There is no chat, no user-generated content, and no communication between users.
External links are limited to opening an observing spot in a maps application and to our own website.
We do not knowingly collect any information from children, and we collect nothing that would fall under
the U.S. Children’s Online Privacy Protection Act (COPPA) or Japan’s Act on the Protection of
Personal Information.

8. Access, correction, and deletion requests

We hold no personal data about you, so there is nothing for us to disclose, correct, or delete.
The settings and collection stored on your device can be erased completely by uninstalling the App.

9. Security

All network communication made by the App uses HTTPS. The App implements no proprietary encryption
and relies solely on the standard transport encryption provided by the operating system and its libraries.

10. Changes to this policy

We may revise this policy when the law changes or when we add features. If a change is material, we will
update the “Last updated” date above and note it in the App’s release notes.

11. Contact


Company	Hoshihaku, Inc. (ホシハク合同会社)
Representative	Nobunari Arakaki, Managing Partner
Address	1050-7 Hirae, Ishigaki City, Okinawa 907-0003, Japan
Email	info@goattours.com
Phone	+81 90-9382-0744
Website	https://goattours.com

Privacy enquiries: info@goattours.com

Appendix: Data sources and licences

The App’s sky data comes from the following open datasets, credited in the App’s in-app credits screen.

Star catalogue: HYG Database v3.8 (CC BY-SA 4.0, astronexus)
Constellation lines and Milky Way: d3-celestial (BSD 3-Clause, Copyright (c) 2015, Olaf Frohn)
Ephemeris calculations: astronomy-engine (MIT License)
Weather data: Open-Meteo (CC BY 4.0)

Submission note (remove before publishing)

Both App Store Connect and Google Play Console require a publicly reachable URL for the privacy
policy. Publish this at a permanent address such as goattours.com/hoshizora-privacy-en/ rather than
submitting the Markdown file, and link it from the App’s Settings > About screen.