Night Logic
Tonight’s targets, ranked
Everything above your horizon tonight is scored and sorted, so the best thing you could point at is the first thing you see. Nothing is up? It says so, instead of burying it.
Astrophotography planner for iPhone · Android coming soon
Stop guessing what to shoot — and how long to expose it.
Night Logic scores every target above you tonight against your sky, your location, and the exact telescope, mount, and camera you own. Then it hands you a real exposure plan: sub length, shot count, and how good the stack will actually get.
3,000+
Deep-sky targets
110+
Scopes & cameras built in
16
Nights of forecast
10
Factors per grade
What it does
Every answer is calculated for your rig, not a generic one.
Most planners tell you what is up. Night Logic tells you what is worth your night — because it knows your aperture, your focal length, your mount’s tracking, your sensor, and how bright your sky is going to be.
A real exposure plan
PROSuggested sub length with the reason it is capped there, the share of frames you’ll lose to star drift, and an integration ladder showing what two, four, or eight hours of data actually buys you.
Grades you can interrogate
Every score opens into the ten factors behind it — optical speed, framing, field rotation, sub-exposure efficiency, moonlight — each one explained in plain language. No black-box number.
Live sky conditions
Cloud cover, seeing, transparency, moon phase and illumination, and the best window tonight — pulled live for your coordinates. Pro extends it to a 16-night outlook so you can plan the whole run.
When it’s up, and where to point
A viewing window for every target: its altitude and compass direction hour by hour, with true astronomical dark highlighted, so you know when to start and which way to aim.
Framing on your sensor
See the target drawn inside your actual field of view, at your focal length, on your sensor format. Find out it won’t fit here, not at 1 a.m. with the mosaic already half shot.
Your sky darkness, estimated
A Bortle class is derived from where you are observing, and every score respects it — or override it if you know your site better than a model does. Save separate locations for home and the dark site.
Your gear, already in there
Forty telescopes and seventy-plus cameras come preloaded with real specs, plus binoculars, mount types, and sensor formats. Anything missing you can enter by hand, and keep as many rigs as you own.
Nothing leaves your phone
No account, no sign-in, no analytics, no ads. Your location and equipment live in local storage on your device — the only thing sent anywhere is the coordinates needed to fetch a weather forecast.
In the app
See what tonight looks like.
Real screens from Night Logic: a ranked target list, the exposure plan, framing on your sensor, a viewing window, and a share card for the finished shot.
Every target graded for your setup
Difficulty is scored for your exact telescope, mount, and camera, with tonight's sky verdict, cloud cover, and moon at the top.
Your session plan, done for you
Exposure per shot, bankable time, and drift loss, plus an integration ladder from Starter to Deep. (Pro)
Check the framing before you shoot
See how the target fills your camera's field of view at your focal length, before you set up.
See when it's up and where to point
Altitude and direction all night, with true astronomical dark highlighted.
Share your night sky
Turn any session into a shareable image or video that includes your gear details.
The part nobody else answers
“How long do I expose for?”
It is the question that costs imagers the most nights, and the honest answer depends on maybe a dozen things about your setup and the sky above it. Night Logic works through all of them and gives you a number — along with the reason it landed there.
- Sub length that respects your mount. Capped by tracking accuracy, sky glow, or the point where one lost frame costs too much — and it tells you which.
- Drift loss, up front. The percentage of subs you should expect to throw away, so your shot count is the real one.
- An integration ladder. What one hour gets you versus four versus eight, on this target, with this rig, under this sky.
- Tonight’s time budget. Whether the window actually banks enough usable exposure to reach a viable stack before dawn.
- Planets get their own math. Bright targets switch to lucky imaging — frame exposure in milliseconds, and how long you can record before rotation smears the stack.
Exposure plan
PRO
Exposure per shot
120s
Suggested 120s — your equatorial (tracking) mount starts trailing stars past this. Shorter subs lose fewer to drift but need more shots to add up.
Shots lost to star drift
~8%
Trailed or unusable subs discarded from the stack — shortening exposure per shot cuts this down.
Integration ladder
4h 20m
2h 00m
Starter
4h 00m
Solid — tonight
6h 00m
High-end
Tonight’s window comfortably outlasts what this target needs.
Under the grade
Ten factors, all of them yours.
A target fit score is not a vibe. It is these, weighed against tonight’s conditions and your equipment, and every one of them opens up to tell you what it measured and why it mattered.
Achievable quality tonight
Optical speed (f-ratio)
Framing (focal length)
Sky darkness
Peak altitude
Imaging altitude window
Field rotation
Sub-exposure efficiency
Seeing vs. focal length
Moonlight
Not shooting tonight? Leave the camera out and the app grades for the eyepiece instead — aperture fit, brightness against sky glow, altitude, hours above the horizon, and moonlight.
Setup takes about a minute
Four answers, and you’re set up for good.
STEP 01
Where you observe
Use your device location or search for a site. Everything — what is up, when it peaks, how dark it gets — is computed from here, in that location’s own time zone.
STEP 02
What you look through
Pick your telescope or binoculars, the mount underneath, and the camera if you shoot. Aperture, tracking, and sensor drive every number that follows.
STEP 03
Go shoot the plan
Open it at dusk and the ranking is already rebuilt for tonight. Tap a target for its exposure plan, framing preview, and viewing window.
Pricing
Free is genuinely usable.
Planets, the full Messier catalog, tonight’s conditions, and equipment-fit grading cost nothing and never expire. Pro adds the depth.
Free
$0
No account, no trial timer, no ads.
- All planets and the 108 Messier objects
- Tonight’s live sky conditions and moon
- Target fit and equipment grading
- Framing preview and viewing windows
- Unlimited saved equipment configurations
Android version coming soon to Google Play.
Pro
Monthly, yearly, or lifetime
Current prices are shown in the App Store (and in Google Play once Android launches).
- Everything in Free
- The full exposure plan — sub length, drift loss, integration ladder
- 2,900+ NGC and IC objects
- 16-night weather and target outlook
- Lifetime option — buy once, done
Learn
Astrophotography, explained plainly.
Short guides on the questions that cost imagers the most nights.
How long should you expose?
Sub-exposure length versus total integration time, with starting points by mount and sky.
The Bortle scale, for imagers
What each class from 1 to 9 means for exposure length, total time, and target choice.
What to photograph tonight
Altitude, Moon, surface brightness and framing, plus classic targets by season.
Which astro app for which job
Planetariums, photo planners, forecasts, and deep-sky planners compared by purpose.
Questions
Before you download.
What is Night Logic: Astrophotography?
Night Logic: Astrophotography is a free iPhone app for planning astrophotography. It scores every deep-sky target above your horizon tonight against your location, sky darkness, the Moon, and the exact telescope, mount, and camera you own, then builds an exposure plan with sub-exposure length, expected frame loss, and total integration time. Android is coming soon to Google Play.
How is it different from Stellarium or PhotoPills?
Planetarium apps like Stellarium show you what is in the sky, and photo planners like PhotoPills help you plan wide-field and landscape shots. Night Logic answers a narrower question: given your specific telescope, mount, camera, and sky, which target is worth shooting tonight and how long should you expose? Many imagers use it alongside a planetarium and a weather app.
Is Night Logic free?
Yes. Night Logic is free to download and includes the planets, all 108 Messier objects, tonight’s live sky conditions, equipment-fit grading, viewing windows, and framing previews, with no account and no ads. Pro adds the full exposure plan, 2,900+ NGC and IC objects, and a 16-night outlook, as a monthly, yearly, or lifetime purchase.
Do I need a telescope to use it?
No. Naked eye and binoculars are both first-class options in setup, and the app grades for what you actually have. Without a camera it scores targets for visual observing rather than imaging.
My scope or camera isn’t in the list.
You can enter any rig by hand — aperture, focal length, mount type, sensor format and resolution — and it is treated exactly like a preloaded one. There is also a calculator for filling in specs you only half know.
Where does the weather data come from?
Open-Meteo, queried live for your observing coordinates. Cloud cover, wind (which drives the seeing estimate), humidity, precipitation probability, and sunrise/sunset all come from there; moon phase and illumination are computed on the device.
Is there an Android version?
Coming soon. Night Logic is on iPhone today, and the Android version is heading to Google Play.
Does it need an internet connection?
Only for weather and for searching locations. Target positions, altitudes, rise and set times, framing, and the exposure math are all computed on your phone, so the planning still works without a signal at a dark site — it just falls back to your last-known conditions.
What happens to my data?
It stays on your phone. There is no account, no server of ours, no analytics SDK, and no advertising. Deleting the app deletes everything it stored. The Privacy Policy spells out the specifics.
How do I cancel a subscription?
Through Apple, in Settings › your name › Subscriptions on your iPhone. Subscriptions are billed by Apple, so cancellation and refunds run through them rather than through us.
Clear night coming?
Set up once, and every night after that opens with the answer already worked out.
Download on the App Store