One File · Powerful fitness tracker
Every session.
Every Messier object.
A stargazing log in one HTML file. Sessions, observations, sketches — and a Messier-list progress banner that ticks 1-110 as you observe.
One payment · Yours forever · 14-day refund
- Works fully offline
- Installs as an app (PWA)
- No account, ever
- Yours, forever
Loads once, never needs the internet again. On a plane, in a basement, in a foreign hotel.
Every entry, every chart — stored locally. We never see it. We can't.
No subscription. No upgrades. No re-up next year. One file, yours.
Why log
Why amateur astronomers keep notebooks.
The list is the practice; the practice is the list.
Messier list completion is the marathon.
M1-M110 over a year is a respectable feat. The dashboard banner ticks toward it; Caldwell + NGC follow.
Bortle scale per session is honest.
Not every clear night is dark. The Bortle field tracks where you actually observed and what was possible.
Sketches survive cloud nights.
What you saw at the eyepiece. The gallery preserves a year of patient drawing.
By-type donut shows depth.
After 100 observations the by-type donut tells you whether you've leaned planet, galaxy, or open cluster.
across 6 dark sites
with real Messier IDs
no recurring fee, ever
no signal in the dark; the log works
Inside the file
Eight things you'll use every day. Plus a dozen more.
One file. One dashboard. Every feature you'd expect from a "real" app — without the cloud, the cookies, or the £8/month.
Quick add
Log an observation from the home screen — three taps and back to your day.
Live insight banner
The single number that matters today, computed in real time from your entries.
Streak calendar
Daily streak across the last weeks. Showing up becomes the default.
Tier progression
Lifetime totals roll into satisfying tier badges as you log.
By type
Visual split across categories so the pattern becomes obvious without squinting.
Searchable, sortable list
Every entry findable in seconds — search across notes, sort by anything.
Photo per entry
Optional photo field stored locally as base64 — never uploaded.
PNG share cards
One-tap share card of your stats, ready for Instagram or a group chat.
Offline, always
Loads once, runs forever without a network connection.
Installs as a PWA
Add to home screen — opens like any native app.
CSV in / CSV out
Bring your old data in. Take everything with you. No lock-in.
No account, ever
No email, no signup, no analytics, no third-party tracking.
Yours forever
If we vanish tomorrow, your tracker keeps working — local file, no server.
Light + dark
Auto-follows the system. Or pick one and stick with it.
Today
Today, at a glance.
The home screen pulls together what just happened and what's coming up — clean enough to actually look at every morning.
- Live insight banner — your unique angle, computed from your entries
- Four-tile stat grid surfacing the numbers that matter today
- Streak calendar showing the last weeks at a glance
- Quick-add button — log without leaving the home screen
- Recent entries on the dashboard so the last log is one tap away
Sessions
Every session, in one place.
Night of, where, bortle scale, seeing per row. Sortable, searchable, groupable.
- Search across where, notes
- Sorted by night of (newest first)
- 9 fields per entry — the right amount of detail
Observations
Every observation, in one place.
Date, object, type, catalogue per row. Sortable, searchable, groupable.
- Search across object, notes
- Sorted by date (newest first)
- Group by type with one tap
- 10 fields per entry — the right amount of detail
Gallery
The whole jungle.
Every plant photo, in one grid. Tap any to see it full size.
- 9 fields per entry
How it's different
What you give up vs. astronomy apps. Plate-solving.
Compared with subscription astronomy apps.
- Pricing modelPay once · $8.99£8 – £15 / month, forever
- Account requiredNoYes
- Real-time sky mapNoYes
- Messier-list completion bannerYesLimited
- Bortle / seeing per sessionYesYes
- Data stays on your deviceYesNo
- Public observation feedNoYes
The promise
Your observation log is yours.
Not a database's record.
Offline, always
Open it once, never need the internet again. The file holds the whole app.
Local-first storage
Every entry stored in your browser, on your device. No server sync. No leaks. Nothing to breach.
One payment, forever
No subscription, no upgrade tier, no nag. If we shut down OneFileClub tomorrow, your file keeps working.
Data does not sync automatically between phone and desktop
This is a local-first app — everything stays on the device you logged it on. To use it on both phone and desktop, use the built-in JSON or CSV export on one device and import on the other when you want to keep them in step.
Every view, light and dark.
A look at every screen across both themes — your tracker, populated.
Questions
Real answers, no fine print.
Does it have a sky map?+
No — that needs accurate ephemeris data and updates. Use a free planetarium app for planning; this is for the log.
Can I import from SkySafari?+
Not directly. CSV import is on the roadmap; current users add as they observe — the act of writing the object cements memory anyway.
Where is my data stored?+
Locally, in your browser, on your device. Nothing is sent to OneFileClub or anyone else — there is no account, no cloud sync, no analytics.
Does it work offline?+
Yes. Once your personalised copy loads the first time, the entire tracker runs from a single HTML file. Airplane mode is fine.
What does 'personalised copy' mean?+
When you buy, OneFileClub stamps a private copy with your licence and deploys it to a unique URL just for you. You bookmark it, install it as an app, or save the file — and the file is yours, even if OneFileClub disappears tomorrow.
What is your refund policy?+
14 days, no questions asked. Email us, we'll process it and disable your private URL.
One payment.
A logbook of dark sky.
We'll personalise a copy and email you a private link. Bookmark it, install it as an app, take it to the next dark site.
14-day refund · No subscription
