NS Draconis / NS Dra
Light curve and phase diagram of the EA type eclipsing binary NS Draconis / NS Dra, constructed from photometry of 72 images taken between 2017 July 28 and 2018 March 11 by the Open University COAST telescope. The images were taken with a V filter.
The catalogue period for this star is 50.517 days (GCVS, AAVSO VSX and Kreiner.) Plotting a phase diagram with this period gives the following result;
The secondary minimum - all two data points of it - ('min II') occurs at a phase of approximately 0.63 to 0.65, and an enlarged plot is given below.
This is consistent with the result published by Otero et al (2006) [NS Dra is listed as GSC 04544-00439 with a listed phase of 0.630 for the secondary minimum.] A phase other than 0.5 for the secondary minimum is due to the eccentricity of the component's orbits around the barycentre.
More observations are needed to give more detailed shapes and phases for the minima.
[This page updated 2018 August 16.]