Difficulty rating
Also called: easy, moderate, challenging, very hard, out of reach, visibility.
How hard an object is tonight — easy, moderate, challenging, very hard or out of reach — for your sky, instrument and Moon.
AstroPilot works out how much an object stands out from the sky background at its best moment tonight, using its surface brightness and size, your sky's darkness (bortle scale), your instrument's aperture, the moonlight and extinction at its altitude — following how the eye detects faint light. Easy objects show at a glance; challenging ones need averted vision and patience.
In AstroPilot
Every object card and page; Explore ranks objects by it.