Save observing sites — each bundles a location and its own horizon profile. Selecting a site loads both at once.
Define obstructions for this site below. Trees, buildings, or terrain.
Set minimum visible altitude at each compass bearing. 0° = open horizon, 30° = blocked to 30° elevation.
Click or drag on the chart to draw your horizon profile. The red line is your current horizon mask.
Stand at your observing site and hold your phone upright in portrait mode. Point the top edge of the phone at the obstruction (treetop, roofline) so it lines up with the top of your screen. Tap Record at each bearing.
Check the filters you own. Expanded object cards recommend which (if any) helps for that target.
Create an account to sync your telescopes, eyepieces, filters, observations, queue, and settings across all your devices. The app still works offline — your data syncs when you're online and logged in.
Night Crazy is an observing planner for visual astronomy and astrophotography. Enter your location and it calculates which of 3,200+ objects — galaxies, nebulae, clusters, double stars, and the planets — are observable tonight and when, accounting for your telescope, your sky conditions, the Moon, and the obstructions around your observing site.
Everything runs in your browser and works offline. Your telescopes, eyepieces, filters, observations, queue, sites, and settings save on your device, and an optional free account syncs them across devices.
This app was inspired by and includes data from the Imm Deep Sky Compendium, created by Gary Imm — a prolific deep-sky astrophotographer whose compendium catalogs thousands of objects with observing notes, ratings, and imaging details. His website at garyimm.com hosts an extensive collection of his astrophotography, detailed object data, and links to his publications, and is well worth exploring.
Galaxies, nebulae, clusters, planets, and curated double stars across all major catalogs.
Altitude and direction for your exact location, date, and time.
All 8 planets with live position, magnitude, phase, and angular size.
75 curated pairs with separation, colors, and split difficulty for your aperture.
Sunset, astronomical dark/dawn, moonrise/set, age, and illumination.
Hourly bars show how high and which direction, all night long.
Save unlimited scopes and switch the active one in a tap.
Magnification, true field, exit pupil, and best-match suggestions.
Per-object advice on which filter helps — and when to use none.
Tells you whether each object is within reach of your scope and sky.
Save locations with their own horizon profiles; switch in one tap.
Define trees and buildings three ways — including a phone-sensor survey.
Limit to the slice of sky you can actually see — great for balconies.
Build a target list, sort by transit, export to text or SkySafari.
One tap shows only what's above the horizon right now, with direction.
Optional account syncs everything across your devices.
At the top of the Objects tab:
| Setting | What it does |
|---|---|
| Latitude / Longitude | Your observing location. Tap 💾 Save Location to store typed coordinates, or allow geolocation to auto-fill. |
| Date | The night you're planning for — evening through the next morning. |
| Timezone | Auto-detected with DST. Change only when planning for another zone. |
| Min Alt | Hides objects that never rise above this altitude. 20° avoids horizon murk. |
| Max Alt | Hides objects that only appear higher than this — useful when a balcony roof or overhang blocks the overhead sky. |
Changing any of these recalculates the list automatically.
The band below the settings shows the night's key times:
Each object is a card with its name, type, nickname, visibility badge, and key stats. Tap a card to expand it for full detail:
Best visibility tonight, name, rating, magnitude, size, transit time, moon separation, or longest viewing window.
Each card shows colored blocks for every hour from 7pm to 4am. The top number is the object's altitude; below it is the compass direction and degrees (azimuth) at that hour.
| Color | Altitude | Meaning |
|---|---|---|
| Green | 45°+ | Excellent — high and clear |
| Dark green | 30–45° | Good |
| Amber | 15–30° | Fair — some atmosphere |
| Red | 0–15° | Low — heavy atmosphere |
| Grey | Below 0° | Below the horizon |
The azimuth (compass direction and degrees) appears under each hour, so you know which way to face as the object moves across the sky. Objects that pass near your zenith change direction quickly around their highest point — that rapid swing is normal. Hours blocked by your horizon mask are dimmed and marked with a 🌲 icon. Below the bars, the viewing window shows the time range the object is above your minimum altitude during darkness, and Highest At shows when it peaks, in which direction, and how high.
Tap ⏱ Now (right of the sort bar) to switch into a live "what can I see this minute" view:
Tap the button again to return to the full list and full-night bars.
Tap + Queue on any object to add it. On the Queue tab you can reorder targets, sort by transit time, and export — as plain text or a SkySafari .skylist file.
Each gear section has an Edit button — controls stay hidden until you tap it, so you can view your setup cleanly without changing anything.
Save as many telescopes as you own. The Active Telescope dropdown switches between them — all calculations update for the selected scope. The app shows focal ratio, Dawes limit, and maximum useful magnification.
Add each eyepiece with its focal length and apparent field of view (40°–120°, including 70°). The app shows magnification, true field, and exit pupil, and recommends the best eyepiece to frame each object.
Set your Bortle scale (1 = pristine, 9 = inner city), seeing, and transparency. From these and your aperture the app computes naked-eye and telescope limiting magnitudes, and tells you on each expanded card whether the object is easy, near your limit, or likely too faint. This also powers the "Visually seeable" filter.
On the Scope tab under 🌈 Nebula Filters, check the filters you own (Tele Vue Nebustar, Astronomik OIII, Astronomik UHC are pre-loaded; add your own too). Expanded object cards then recommend which filter helps:
Define the obstructions around your site so the app knows what's actually blocked. Three methods:
Blocked objects are flagged and their blocked hours dimmed. You can save multiple Observing Sites — each bundles a location and its own horizon — and switch between them with the Active Site dropdown. Choosing "Ad-hoc" keeps your current location with an open horizon.
The Stats tab summarizes your logged observations by status, type, and priority.
From the Queue tab, Export SkySafari creates a .skylist file. Open it on your phone and choose SkySafari — your targets appear under Observing Lists, identified by their best catalog number.
An account is optional — the app works fully without one, storing everything on your device. On the Account tab you can register or log in to sync your telescopes, eyepieces, filters, observations, queue, sites, and settings across all your devices.
To protect your dark adaptation at the eyepiece, the app offers two screen modes, chosen by the toggles in the tab bar. They're mutually exclusive — turning one on turns the other off — and your choice is remembered between sessions.
If you place a physical red filter over your screen, the app's normal colours become hard to read — red film blocks blue and green almost entirely, so blue accents go nearly black. Grey mode remaps everything to a high-contrast greyscale on black, with heavier text, so that brightness alone carries the information — which is the one thing the filter preserves. The altitude blocks are reshaded by brightness (lighter = higher).
Red mode turns the whole interface to deep red on black — the classic dark-adaptation scheme. It uses only red tones, with no white, blue, or green anywhere, because even small amounts of blue/green light are what degrade night vision. Use this when you don't have a physical filter. The altitude blocks appear as red intensities (brighter red = higher).
Open the site in Safari (iPhone) or Chrome (Android) → Share / menu → Add to Home Screen. It launches full-screen with the Night Crazy icon, like a native app. If you update the app and the icon still shows an old version, remove the icon and clear the site's data, then re-add it.
Objects with very southern (or northern) declinations may never rise from your latitude. Seasonal objects like M31 in late spring only rise near dawn — check the later hours (3am, 4am).
Without an account, data is stored only in that browser and is lost if you clear browser data or use private mode. Log into an account to sync and protect it across devices.
Planet positions are good to ~1–2 arcminutes; the Moon's to ~0.3°. Twilight and sun times are within a few minutes. Location to two decimal places (~0.7 mile) is plenty — coordinate precision beyond that makes no visible difference.
Galaxies are listed in millions of light-years (Mly) — M51, for example, is about 25 Mly away. Nebulae and clusters are close enough to be shown in plain light-years, and planets in astronomical units (AU). Double-star distances are to the primary star, in light-years.
Yes — once loaded, the planning features work without a connection. Location, sync, and the external image/data links need internet.
Clear-sky wishes — enjoy your time under the stars.