API Reference / skyViewSequence · function

Function: skyViewSequence()

function skyViewSequence(
   engine, 
   view, 
   seq, 
   opts?): SkyViewSequence;

A time sequence of skyView frames for the same place, aim, and lens: the keyframes for an accurate night-sky animation. Each frame is a complete, physically exact spec; across frames the sky rotates about the pole, the Moon drifts and changes phase, twilight evolves, and the Milky Way wheels. The geometry is continuous, so the frames are temporally coherent; supplying them as control images (or reprojecting one rendered plate by the per-frame rotation) is how to keep the rendered output coherent too.

Parameters

Parameter	Type	Description
`engine`	`Engine`	The engine used to evaluate positions.
`view`	`SkyViewSpec`	Observer, aim, lens, and image size, shared by every frame.
`seq`	`SkyViewSequenceSpec`	Frame count and timing (`stepMinutes` or `endJdUt`).
`opts`	`SkyViewOptions`	Per-frame SkyViewOptions (bortle, refraction, bodies).

Returns

SkyViewSequence

A SkyViewSequence: the frames plus timing and the sky's per-step rotation about the celestial pole (each frame carries its pole).

Example

// One frame per 6 minutes for two hours from astronomical dusk
const seq = skyViewSequence(engine, view, { startJdUt: dusk, frames: 21, stepMinutes: 6 });
seq.rotationDegPerStep;        // ~1.5 deg of sky rotation per frame
seq.frames[0].pole;            // the rotation center in pixels

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