DEdicated MONitor of EXotransits and Transients (DEMONEXT)
DEMONEXT, the DEdicated MONitor of EXotransits and Transient, 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 2Kx2K CCD imager and a 10-position filter wheel with an electronic focuser. DEMONEXT can operate in a continuous observing mode and achieve 2-4 mmag raw, unbinned,
precision on bright V < 13 targets with 20–120 second exposures, and 1 mmag precision with 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~21.
Instrument Specification
- Project type: Robotic Telescope System
- Telescope: 0.5m f/6.8 PlaneWave CDK20 Corrected Dall-Kirkham
- Mount: Mathis MI750/1000 fork mount
- CCD Camera: FLI PL23042 2Kx2K
- Field of View: 30.7x30.7 arcminutes
- Filter Wheel: FLI CFW-3-10 10-position filter wheel, 50mm square filters
- Filters: Bessel BVRI, SDSS griz, whitelight, and diffuser
- Additional Systems: Orion 80mm ED guide scope + SBIG ST402ME CCD; Hedrick electronic focuser
- Observatory Site: Winer Observatory, Sonoita, AZ, USA
- Years active: 2016-2022
- Reference: Villanueva et al. 2018, PASP, 130, 5001; Villanueva et al. 2016, SPIE, 9906E, 2L
Instrument Facts
- DEMONEXT was part of the PhD dissertation of graduate student Steven Villanueva
- DEMONEXT was the successor to DEMONEX, an OSU robotic telescope that operated from 2008-2013
- A novel science-guiding mode is used to achieve sub-pixel guiding precision for many hours of continuous time-series imaging.
- The DEMONEXT automated queue observing system 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
- While designed for exoplanet follow-up, ancillary science projects include Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation
- Jointly operated by OSU and Vanderbilt from 2016 until retirement in 2022
- DEMONEXT returned to OSU in 2023 and will be reconfigured and redeployed at another observatory site in late 2024/early 2025.
Instrument Team
Steven Villanueva (Project Lead)
Scott Gaudi (PhD co-advisor)
Richard Pogge (PhD co-advisor)
Jason Eastman (technical advisor)
Jon Shover (instrument maker)
Dan Pappalardo (electronics engineer)
Keivan Stassun (Vanderbilt collaboration lead)
Mark Trueblood (Winer Observatory)
Patricia Trueblood (Winer Observatory)