This article [J. Astron. Telesc. Instrum. Syst. 4(4), 046003 (2018), doi: 10.1117/1.JATIS.4.4.046003] was originally published with an error in an equation.
Equation 1 originally appeared as
The equation has been corrected to
All online versions of the article were corrected on 15 November 2018. The article appears correctly in print.