The milliArgus Hercules Mount: Shouldering the Weight of the Argus Optical Array

As technological improvements continue to lower manufacturing costs, telescopes are becoming cheaper and more accessible to a wider community. A telescope with an 8-inch collecting area is now orders of magnitude cheaper than it was 20 years ago for the same surface quality or better. The Argus Optical Array takes advantage of these advances to create an all-sky, arcsecond resolution, high-cadence telescope array with a cost in the $20M range. The completed array will be a 5-m class telescope consisting of over 900 individual telescopes observing the entire Northern sky simultaneously at a 1-minute cadence, and with its low-noise CMOS detectors, the array is capable of observing at second-timescales for short periods. The series prototype, milliArgus, is a downscaled model of the full-sized array and consists of nine 8-inch telescopes under a hemispherical dome mounted onto a semi-fixed equatorial mount. The mount is capable of adjusting its Polar axis alignment via two high-precision linear actuators while sustaining a load of over 800 lbs. including counterweights. The dome is decoupled from the platform that supports the telescopes to minimize the effect of windshake during observations. Sidereal tracking is performed by two linear actuators that are connected to the outer dome and the telescope platform respectively and track synchronously with arcsecond precision. Three of the mount’s key components were fabricated by the on-campus machine shop using high precision CNC routing machines. The rest of the mount is constructed from widely-available, low-cost commodity materials some of which were welded together to provide structural support and stability. The Hercules mount is designed to scale up to the next telescope in the Argus series of prototypes: Argus Pathfinder. The Pathfinder mount will support at least 150 telescopes, 10,000 lbs. of weight, and has similar arcsecond-accuracy tracking requirements. Here we present on-sky results of the Hercules mount and our plans for the next generation of Argus prototypes.