A planet in motion
In video, the rapid spin and swirling air currents of Jupiter come dramatically to life
The banded atmosphere of Jupiter, full of everchanging detail, is an amazing sight to observe and image with a medium to large aperture reflector of
6 inches (150mm) upwards. Some features, such as the Great Red Spot, are large and obvious to see, while others may be subtle, appearing like small areas of noise on single still images. This is where animation really comes into its own. In an animated sequence, disc noise disappears between frames, while real features persist and rotate with the planet.
There is some motion within Jupiter’s atmosphere, but this is hard to see unless you’re using special techniques. For example, with careful planning and luck with the weather, it should be possible to take an image of Jupiter at the same longitude over many rotations. Animating these will then reveal atmospheric features drifting and developing over time.
Typically Jovian animations are done with frames recorded at regular intervals over an extended time of many minutes or hours. These sequence animations use the planet’s limb as the anchor reference, the result showing how the features come and go as Jupiter rotates on its axis.
With each rotation taking less than 10 hours, the results can be quite spectacular.
To capture images for an animation, a polar-aligned tracking equatorial mount is highly recommended. As well as keeping the planet in position on the camera sensor chip, this removes the need for post-capture orientation adjustment, as each image will have the same orientation.
As was the case with the moon animation, carefully consider what the capture frequency should be. Bear in mind high-frame-rate captures typically require 30 to 60 seconds to record. A sequence of, for example, 50 seconds capturing the frames, then waiting 10 seconds, followed by another 50 seconds of capture and 10 seconds of waiting, will produce a very smooth animation but will also be labour-intensive.
Longer intervals between captures take the pressure off, but the final animation won’t be as smooth. Longer gaps also have the advantage of less data to handle and less post-capture processing to do. It’s your choice, but we’d recommend looking at a starting figure of 10 minutes between frames.
The shadows cast by transiting moons make for particularly striking animations, providing good motion and image contrast with the steadily rotating Jovian globe. Moons involved in other events make excellent targets too. For example, consider animating a moon moving behind (occultation disappearance) or being revealed by (occultation reappearance) Jupiter’s globe. Alternatively, a moon being hidden (eclipse disappearance) or revealed (eclipse reappearance) by Jupiter’s shadow can make for a dramatic sight through larger apertures.