Astrophotography Framing Assistant Visualize your camera field of view with any telescope and camera combination. Uses real sky survey data.
Visual Astronomy Assistant Visualize your field of view with any telescope and eyepiece combination. Uses real sky survey data.
Jupiter Great Red Spot Calculator Find out when the Great Red Spot faces Earth. Predicts upcoming transits from Jupiter's System II rotation.
Equipment Comparator Put two or three telescopes, cameras or eyepieces side by side, spec against spec.
Focus Step Calculator Get the autofocus step size for your focuser, telescope and camera in each capture program, then check it on a simulated run.
Flat Frame Dust Distance Finder Find the dust donuts in a flat frame and work out whether the dust is on the sensor, the camera window or a filter.
Comet Finder See which comets are up from where you stand, where to look and how bright they should be, from today’s orbits.
Planetary Imaging Barlow Calculator Find the focal ratio your camera wants for planetary imaging, and the Barlow that gets your telescope there.
Guide Camera Suitability Calculator Check whether your guide camera and guide scope or off-axis guider suit your telescope: the scale ratio, binning for PHD2 and how easily a guide star is found.
Launch Visibility Planner Will you see the rocket jellyfish tonight? Check the conditions for an upcoming launch, the time, and where to look.
ISS Transit Finder Find when the International Space Station crosses the Sun or the Moon near you, and how far to go to see it.
Vignetting Calculator Find how wide an adapter, spacer or filter must be between your telescope, reducer and camera, and how much light the corners lose when it is too narrow.
Stonyhurst Solar Overlay Draw the heliographic grid on your own white-light photo of the Sun for the moment it was taken, and read a sunspot's latitude and longitude off it.
Solar Ruler Measure how high a prominence stands and how long a filament runs, in kilometres, on your own photo of the Sun, with Earth and Jupiter to scale.