AstroTonight

AstroTonight shows you what's worth photographing in the night sky tonight, from exactly where you're standing.

Tell it where you are and how dark your sky is, and it ranks galaxies, nebulae, star clusters and the planets by how well they'll image: how high they are, how well they stand out against your sky, where the Moon is, and how popular they are with astrophotographers.

TONIGHT'S BEST TARGETS
• 768 targets: every Messier and Caldwell object, bright NGC and IC objects, and about 160 favourite astrophotography targets such as the Horsehead, Heart and Soul, the Carina Nebula and the Magellanic Clouds
• Planets included and positioned live
• Ranked for your sky, using its Bortle class or your sky quality meter reading
• Difficulty from Easy to Very hard, with a plain explanation of why
• A narrowband / dual-band filter setting for emission nebulae
• Sort by best target, magnitude, altitude, time available tonight, size or name, and filter by type
• Search any target by name, catalogue number or constellation

PLAN ANY NIGHT
• Now updates every minute, and during the day it shows tonight from when it gets dark
• Pick any date and scrub through the night with a slider
• Each target's chart shows its altitude through the night, the darkness window, the Moon and your skyline
• See imageable time, highest point in darkness and when it crosses the meridian

MAP YOUR SKYLINE
• Use the camera to trace the trees, roofs and hills around you: hold the button and sweep along the skyline
• Targets hidden behind your skyline are marked as blocked
• Save several sites, each with its own sky darkness and skyline

FIND IT WITH THE CAMERA
• The live camera view labels the horizon, compass points, bright stars, planets, the Moon and tonight's best targets
• Pick a target and follow the arrow ("Turn left 30°, raise 15°") until it's in the crosshair
• Align the compass on a bright star if a metal tripod or phone case throws it off

FRAMING FOR YOUR TELESCOPE
• Built-in fields of vi…