The DEdicated MONitor of EXotransits and Transients (DEMONEXT): System Overview and Year One Results from a Low-Cost Robotic Telescope for Follow-Up of Exoplanetary Transits and Transients

Abstract

We report on the design and first year of operations of the DEdicated MONitor of EXotransits and Transients (DEMONEXT). DEMONEXT is a 20 inch (0.5-m) robotic telescope using a PlaneWave CDK20 telescope on a Mathis instruments MI-750/1000 fork mount. DEMONEXT is equipped with a $2048\times 2048$ pixel Finger Lakes Instruments (FLI) detector, a 10-position filter wheel with an electronic focuser and $B$, $V$, $R$, $I$, $g^{\prime }$, $r^{\prime }$, $i^{\prime }$, $z^{\prime }$, and clear filters. DEMONEXT operates in a continuous observing mode and achieves 2-4 mmag raw, unbinned, precision on bright $V<13$ targets with 20-120 second exposures, and 1 mmag precision achieved by binning on 5-6 minute timescales. DEMONEXT maintains sub-pixel ($<0.5$ pixels) target position stability on the CCD over 8 hours in good observing conditions, with degraded performance in poor weather ($<1$ pixel). DEMONEXT achieves 1-10% photometry on single-epoch targets with $V<17$ in 5 minute exposures, with detection thresholds of $V\approx 21$. The DEMONEXT automated software has produced 143 planetary candidate transit light curves for the KELT collaboration, and 48 supernovae and transient light curves for the ASAS-SN supernovae group in the first year of operation. DEMONEXT has also observed for a number of ancillary science projects including Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation.

References in corpus (5)

• The Transiting Exoplanet Survey Satellite
• Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence
• MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand
• KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603
• Miniature Exoplanet Radial Velocity Array (MINERVA) I. Design, Commissioning, and First Science Results

Cited by in corpus (3)

• Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star
• TESS Shines Light on the Origin of the Ambiguous Nuclear Transient ASASSN-18el
• K2 Optical Emission from OJ 287 and Other Gamma-Ray Blazars on Hours-to-Weeks Timescales from 2014-2018