Observing Notebook

Your observing records belong to you — not a server, not a subscription, not a sign-up form.

Observing Notebook is an offline iPhone logbook for amateur astronomers who keep sessions in Excel or on paper and have had enough of planetarium apps that bury the logbook behind a $49/year wall. One purchase. No account. No cloud. All data stays on your device.

PLAN TONIGHT'S SESSION
See which deep-sky objects are actually visible from your location tonight. The built-in planner computes rise, set, transit, and maximum altitude for every Messier, Caldwell, and curated NGC/IC object in the offline catalog — without a network connection. Filter by observing list, object type, constellation, or observed/unobserved state. Select your targets and start a planned session in one tap.

LOG FAST IN THE FIELD
Quick-log mode captures what matters immediately: target, rating, short note, and time. Fill in the rest later. Eyepiece, filter used, seeing, transparency, Bortle class, sketch note — the full observation form is there when you want it, out of your way when you don't. Defaults carry over from your last session so repeated entry stays minimal.

BROWSE THE OFFLINE CATALOG
Messier 110 objects, Caldwell 109 objects, a curated selection of bright NGC/IC showpieces, and solar-system reference entries for Mercury through Neptune and the Moon — all bundled, all available with airplane mode on. Each object detail shows rise/set/transit for tonight, your full observation history, and actions to log, plan, or add to a list.

TRACK YOUR OBSERVING PROGRAMS
Built-in Messier and Caldwell checklists show real progress derived from your logged observations, not a manual tally. Create custom lists for your club program or personal projects. Filter by visible tonight, unobserved, type, or constellation. Progress like 47/110 updates every time you log.

NIGHT MODE & EXPORT
True-black background with deep-red controls protects your dark adaptation in the field. Export your full log to CSV or JSON and share through the iOS share sheet — to Files, AirDrop, email, or any cloud drive you choose. Your data, your format.

PRIVACY BY DESIGN
No account. No login. No tracking. No analytics. No ads. App Store privacy label: Data Not Collected. One-time purchase — nothing unlocks later, nothing expires.

Observing Notebook is not a planetarium. It does not show a star map, track objects in real time, or control mounts. It is the serious field notebook that serious observers actually need.