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. It calculates which of 3,200+ objects — galaxies, nebulae, clusters, double stars, and the planets — are visible from your location on any given night, taking into account your telescope, your sky conditions, the Moon, and obstructions around your observing site.
Everything runs in your web browser. Your telescopes, eyepieces, observations, queue, and horizon profile are all saved locally on your device between sessions.
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 for anyone interested in deep-sky observing and imaging.
Galaxies, nebulae, clusters, planets, and curated double stars across all major catalogs.
Altitude calculated 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.
Exact time range each object clears your horizon during darkness.
Save unlimited scopes and switch the active one with a tap.
Magnification, true field, and exit pupil per eyepiece — plus best-match suggestions.
Tells you whether each object is within reach of your scope and sky.
Define trees and buildings three ways — including a phone-sensor survey.
Build a target list, sort by transit, export to text or SkySafari.
Mark priority, status, and notes for every object.
One tap shows only what's above the horizon right now.
Track what you've observed and imaged by type and status.
Detects your coordinates and timezone (with DST) automatically.
When you first open the app:
At the top of the Objects tab:
| Setting | What it does |
|---|---|
| Latitude / Longitude | Your observing location. Tap 📍 My Location to auto-fill. |
| Date | The night you're planning for. Calculations use this date's evening through next morning. |
| Timezone | Auto-detected with DST. Change only if planning for a different zone. |
| Min Altitude | Hides objects that never rise above this altitude. 20° is a good default to avoid horizon murk. |
Changing any of these recalculates the entire list automatically.
The band below the settings shows the key times for the night:
Each object appears as a card showing its name, type, nickname, visibility badge, and key stats. Tap a card to expand it for full details:
Sort by best visibility tonight, name, rating, magnitude, size, transit time, moon separation, or longest viewing window.
Each card shows colored blocks for every two hours from 7pm to 4am. The number is the object's altitude in degrees at that time.
| 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 |
Below the bars, the viewing window shows the exact time range the object is above your minimum altitude during astronomical darkness.
Tap ⏱ Now (right side of the sort bar) to filter the list to only objects above your minimum altitude at this exact moment, respecting your horizon mask. Each card shows a green "Alt Now" value. Tap again to turn it off.
Tap + Queue on any object to add it to your session list. On the Queue tab you can:
.skylist file you can open directly in SkySafariSave as many telescopes as you own. Use the Active Telescope dropdown to switch — all calculations (limiting magnitude, eyepiece matches, split difficulty) update for the selected scope. Use + Add New to create one and Delete to remove it.
The app automatically calculates focal ratio, Dawes limit (resolving power), and maximum useful magnification (2× aperture in mm).
Add each eyepiece with its focal length and apparent field of view. The app shows magnification, true field of view, and exit pupil for each. When you expand an object, it recommends the eyepiece that best frames that target.
Set your Bortle scale (1 = pristine dark, 9 = inner city), seeing, and transparency. From these and your aperture, the app calculates:
When you expand an object, a note tells you whether it's an easy target, near your limit, or likely too faint. This also powers the "Visually seeable" filter.
If you own nebula filters, add them on the Scope tab under 🌈 Nebula Filters and check the ones you have. The app comes pre-loaded with common filters (Tele Vue Nebustar, Astronomik OIII, Astronomik UHC) and you can add custom ones.
When you expand an object, a 🌈 recommendation tells you which of your filters helps — and crucially, when not to use one:
Define obstructions around your site so the app knows what's actually blocked. Three methods on the Scope tab:
Once set, objects behind your horizon are flagged ⚠ Partially blocked or ⛔ Horizon blocked, and viewing windows exclude blocked time.
The Stats tab summarizes your logged observations — how many you've observed and imaged, broken down by status, object type, and priority.
From the Queue tab, Export SkySafari creates a .skylist file. On your phone, open the file and choose to open it in SkySafari — your targets appear under Observing Lists, identified by their best catalog number (Messier, then NGC, then IC).
From any latitude, objects with very southern (or northern) declinations may never rise. Seasonal objects like M31 in late spring only rise near dawn — check the later altitude slots (3am, 4am).
Personal data is stored in your browser. It will be lost if you clear browser data, use private/incognito mode, or switch devices. It does not sync between devices.
Planet positions are accurate to roughly 1–2 arcminutes — ample for visual observing and GoTo alignment. Magnitudes use the IAU standard formulas.
Within a few minutes of published values — fine for planning. They are computed for your exact coordinates and date.
Once loaded, most features work without a connection. Location and the external image/data links require internet.