The Digital Single Lens Reflex (DSLR) camera combined with a small aperture telescope is an efficient equipment for an astronomy-related lab exercise. This paper compares the different photometry softwares to provide insights on using the GUI-based photometry tool to the conventional command-line based photometry tool. The magnitude of the same point source measured within the aperture is consistent regardless of the software used although the background estimation, partial pixel treatment, and error estimation are slightly different. In a crowded field image where the aperture photometry is less reliable, the aperture photometry with varying aperture size is useful to see the qualitative trend for the magnitude. Due to the variation in ISO settings and the color dependence on the RGB Bayer system, an initial uncertainty of ~0.15mag is expected to be embedded in the magnitude derived from the DSLR images.

We present the results of BV time-series photometry of the globular cluster NGC 288. Ob- servations were carried out to search for variable stars using the Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes and a 4k pre-science CCD camera during a test observation from August to December, 2014. We found a new SX Phe star and confirmed twelve previously known variable stars in NGC 288. For the semi-regular variable star V1, we newly determined a period of 37.3 days from light curves spanning 137 days. The light-curve solution of the eclipsing binary V10 indicates that the system is probably a detached system. The pulsation properties of nine SX Phe stars were examined by applying multiple frequency analysis to their light curves. We derived a new Period-Luminosity (P-L) relation, hMV i = −2.476(±0.300) logP − 0.354(±0.385), from six SX Phe stars showing the fundamental mode. Additionally, the period ratios of three SX Phe stars that probably have a double-radial mode were investigated; PFO/PF = 0.779 for V5, PTO/PFO = 0.685 for V9, PSO/PFO = 0.811 for V11. This paper is the first contribution in a series assessing the detections and properties of variable stars in six southern globular clusters with the KMTNet system.