Find the Spin
Below are 434 real brightness measurements of asteroid 16152, taken over seven weeks with Las Cumbres Observatory telescopes. The asteroid rotates, so its brightness repeats with one true period. Folded at any other period, the data are a cloud of noise. Drag the slider until the measurements line up.
What this demonstrates: period-finding in unevenly sampled time series. The alignment score is a phase-dispersion statistic, the same idea SpinDoc minimizes over thousands of trial periods with a Fourier-series fit, plus corrections for the asteroid’s changing distance and solar phase angle. Watch out for the half-period alias on your way up. Or jump straight to the asteroid’s shape.
So what does 16152 look like?
The same light curve you just folded also encodes shape. Feeding it to Silhouette, my light-curve inversion tool, gives the best-fit spinning ellipsoid below: at least 1.48 times longer than it is wide. And an honest fit reports its limits: one observing season only sets a lower bound on the elongation, so the spin pole and third axis stay undetermined until more viewing geometries are added. Knowing exactly what the data can and cannot tell you is the job.
Best-fit axis ratios a : b : c = 1.48 : 1.00 : 1.00