Tools

Calculators

Astronomy calculators for planning observations, evaluating equipment performance, and optimising your astrophotography setup.

Object Visibility & Sky Position

Check if a celestial object is visible from your location tonight

Calculate the highest point an object reaches in your sky

Find when an object rises, transits, and sets at your location

Determine the optimal time to observe a specific object

Plot how an object's altitude changes throughout the night

Calculate the airmass for an object at a given altitude

Calculate the local sidereal time for your location

Calculate the hour angle of an object

Calculate the magnification for a telescope and eyepiece combination

Calculate the exit pupil diameter for your setup

Calculate how much sky you can see through your eyepiece

Find the highest useful magnification for your telescope

Calculate the theoretical resolving power of your telescope

Find the best eyepiece focal lengths for your telescope

Calculate the faintest objects visible through your telescope

Calculate the surface brightness of extended objects

Convert between apparent and absolute magnitudes

Calculate the image scale for your camera and telescope

Calculate your camera's field of view with your telescope

Determine if your imaging setup is over or under-sampled

Match your pixel scale to atmospheric seeing conditions