This tutorial contains step-by-step instructions for finding the rotation period of minor planet 1036 Ganymed1 using the FALC (Fourier Analysis of Light Curves) method. FALC (Harris et. al., 1989) has been defined by Dr. Alan Harris (JPL), who is one of the most recognized leaders in asteroid research, and is a de facto standard for asteroid light curve period analysis. 


Dr. Harris' method is fully integrated in Peranso, through the Period Determination box and through a dedicated FALC Workbench. The FALC Workbench also provides sophisticated outputs, showing f.i. the uncertainty of the fitted curve. In addition, it allows to keep a period constant while incrementing harmonic orders, to determine the most significant fit order to work with.


Dr. Harris' method is very interesting too for variable star light curve analysis, as it effectively takes into account magnitude error values in the period determination.  


This tutorial contains a section explaining the usage of FALC based on the Period Determination box.  Another section describes the FALC Workbench. You may use either method to do your FALC period analysis.


Asteroid 1036 Ganymed is a 32-km Near-Earth Asteroid (NEA) with a low phase angle and amplitude. It is on a highly eccentric orbit with an orbital period of 1587 days, and was discovered by German astronomer Walter Baade in 1924. It is the largest of all NEAs and has a reported2 rotation period of 10.318 hours based on the observations used in this tutorial.



(1) This tutorial uses data obtained from the Asteroid Lightcurve Data Exchange Format (ALCDEF) database, which is supported by funding from NASA grant 80NSSC18K0851. All observations of 1036 Ganymed used in this tutorial were obtained by the prolific photometrist F. Pilcher (Organ Mesa Observatory, MPC code G50) using a 0.35m f/9.1 SCT.


(2) "Near-earth asteroid lightcurve analysis at the center for solar system studies: 2019 March-July", B.D. Warner & R. D. Stephens, Minor Planet Bulletin 46 (2019), p. 423 - 438