# Clear Night Planner

> Free astrophotography planner: tonight’s cloud, darkness and Moon for your location, with targets and camera settings for your telescope or smart telescope.

Clear Night Planner (https://clearnight.co.uk/) is a free web app for amateur astronomers and astrophotographers. Enter a location and the telescopes, smart telescopes or cameras you own ("outfits"); it combines the night’s weather forecast with each outfit’s optics and mount to suggest what to image tonight and how. Version 1.8.1, updated 23 October 2026. Made in the UK, works worldwide.

## What it does

- Hour-by-hour cloud (low, mid and high), wind, humidity, dew and jet-stream forecast for 48 hours
- Astronomical darkness window, Moon phase, moonrise and moonset for your location
- Target suggestions for deep-sky objects, planets, the Moon, the Sun (with a solar filter), bright asteroids and meteor showers
- Imaging settings per target: exposure length, number of subs, gain or ISO, filter and best time window
- Add your own objects by name or catalogue number (looked up in SIMBAD, NED and VizieR) or by coordinates; each is checked against tonight’s sky and your outfit, with the reasons and the settings to use
- Equatorial (EQ) and Alt-Az mount modes, including field-rotation limits and fixed tripods (NPF rule)
- Presets for ZWO Seestar S30, ZWO Seestar S30 Pro, ZWO Seestar S50, ZWO Seestar S50 Pro, DwarfLab Dwarf 3, DwarfLab Dwarf Mini, DwarfLab Draco (Standard and SHO editions)
- Live readings from the nearest Weather Underground personal weather station
- Location by UK postcode, town name, decimal coordinates or device location
- Red night-vision mode to protect dark adaptation

## Questions and answers

### What does Clear Night Planner do?

It reads the hourly cloud, wind, humidity and jet-stream forecast for your location, works out when it is properly dark and where the Moon is, then suggests what your own equipment can capture that night: deep-sky objects, planets, the Moon and meteor showers. For each target it gives an exposure length, number of subs, gain or ISO, filter and the best time window.

### Which telescopes, smart telescopes and cameras does it support?

Any of them. You describe each outfit by its aperture, focal length, sensor size, pixel size, mount and filters. Presets are included for the ZWO Seestar S30, ZWO Seestar S30 Pro, ZWO Seestar S50, ZWO Seestar S50 Pro, DwarfLab Dwarf 3, DwarfLab Dwarf Mini and DwarfLab Draco (Standard and SHO editions), plus starting points for a telescope with a camera, a camera on a star tracker and a camera on a fixed tripod.

### How are tonight’s targets chosen?

Each target is scored on how many clear, dark hours it spends above your lowest useful altitude, how high it climbs, how well it fits your field of view, how bright it is against your sky (Bortle scale), how close and bright the Moon is, and the longest exposure your mount allows in EQ or Alt-Az mode. Blocked directions you set, such as houses or trees, are left out.

### Where does the weather data come from?

Forecasts come from Open-Meteo’s weather models, refreshed hourly. Current conditions come from the nearest Weather Underground personal weather station within 15 km when one is reporting. Sun and Moon positions are calculated with SunCalc, and planet positions from NASA JPL’s approximate orbital elements.

### Does it work outside the UK?

Yes. Search for a town anywhere, enter decimal coordinates or use your device’s location. Postcode search covers UK postcodes.

### Do I need an account?

No. Without signing in, your outfits and settings are saved in your browser on that device. Signed-in accounts keep them on the server, so they appear on any device, and can add their own Weather Underground station.

### Why are exposures shorter in Alt-Az mode?

An Alt-Az mount keeps a target centred but the field slowly turns, which trails stars at the edge of the frame. The planner works out the rotation rate for each target and time from your latitude and caps the exposure to match. EQ mode, or a smart telescope with a rotating sensor such as the DwarfLab Draco, avoids this.

### Is Clear Night Planner free?

Yes. It is free to use, with no adverts.

## Data sources

- Weather forecast: Open-Meteo (https://open-meteo.com/)
- Current conditions: Weather Underground personal weather stations (https://www.wunderground.com/)
- UK postcodes: postcodes.io (https://postcodes.io/)
- Sun and Moon: SunCalc (https://github.com/mourner/suncalc)
- Planets: NASA JPL approximate orbital elements
- Object names: CDS Sesame name resolver (SIMBAD, NED, VizieR), https://cds.unistra.fr/

## Links

- App: https://clearnight.co.uk/