Software Bisque Paramount Taurus Model 500 Equatorial Fork Mount Direct Drive

Observatory-Grade Mount for 20-inch Telescopes

The Paramount Taurus 500 is engineered for permanent observatory installations housing large-aperture instruments, with a typical optical tube assembly (OTA) size of 20 inches (0.5 m). It is built for astronomers, institutions, and researchers who want precise pointing and tracking for attended, unattended or remote data acquisition.

By combining the stability of a dual-tined fork with direct-drive motors and on-axis absolute encoders, the Taurus 500 serves long-exposure deep-sky imaging and, with the included Satellites module, satellite tracking.

Equatorial Fork Design: Uninterrupted Imaging 6 Hours Past Meridian

The equatorial fork is the defining feature of the Taurus 500, enabling it to track celestial objects continuously from horizon to horizon. This design allows the mount to follow a target for up to 6 hours past the celestial meridian without interruption. There are no interruptions for meridian flips.

Furthermore, the fork design offers far easier eyepiece access for visual observers compared to German equatorial mounts (GEMs), especially with large catadioptric or Cassegrain telescopes. The OTA remains in a comfortable and accessible position throughout the night, making the Taurus 500 an excellent choice for public outreach and educational facilities where both imaging and visual use are important.

Paramount Taurus vs. German Equatorial Mounts: The End of the Meridian Flip

The most significant operational difference between the Taurus 500 and a GEM is the elimination of the meridian flip. This single feature transforms the reliability and efficiency of an automated observatory.

• Workflow Continuity: A GEM must pause imaging at the meridian, rotate the entire assembly, reacquire the guide star, and restart the exposure sequence. The Taurus 500 tracks straight through without that interruption.
• Automation Reliability: The meridian flip is a common point of failure in robotic setups, introducing risks of cable snags, collisions, or re-acquisition errors. Removing this maneuver removes those risks from unattended operation.
• Payload Stability: With a GEM, the telescope is cantilevered off the side of the declination axis, balanced by counterweights. The Taurus 500 cradles the payload between two fork tines, and its dual-tined fork provides exceptional stability for your instruments.

Direct-Drive Motors: 37 Nm of Torque and 30°/s Slewing

The Taurus 500 uses high-performance direct-drive motors on both the hour angle and declination axes. These motors deliver 37 Nm of continuous torque, enabling rapid slewing at speeds up to 30 degrees per second. Because there are no gears, worms, or belts in the drive train, the system has no measurable backlash.

The direct-drive motors mean silent operation and much faster slew speeds, and with the on-axis absolute encoders periodic error is negligible.

26-bit On-Axis Absolute Encoders: 0.02 Arcsecond Resolution

Paired with the direct-drive motors are 26-bit on-axis absolute encoders on both axes. These encoders provide a fundamental resolution of 0.02 arcseconds, ensuring the mount's control system always knows the exact orientation of the telescope with extreme precision. This has two critical benefits for the user.

First, periodic error is negligible. While minor harmonic errors from encoder mounting can exist, the periodic error is negligible. Second, the mount never needs to be homed or initialized. The mount can be restarted (powered off then on) with virtually identical pointing and tracking accuracy from session to session.

TPoint & ProTrack: Pointing Better Than 30 Arcseconds RMS

The Taurus 500's pointing and tracking accuracy also depends on software. The included TPoint software builds a comprehensive model of the entire telescope system, mapping out and correcting for all repeatable, systematic errors. This includes not only mechanical issues like cone error and tube flexure but also optical errors like atmospheric refraction.

Once a TPoint model is created, ProTrack uses it in real time to continuously adjust the mount's position, correcting tracking errors across both axes. All-sky pointing accuracy is 30 arcseconds RMS or less, a figure based on gear-driven models. Direct-drive Paramounts deliver significantly better results. Gear-driven Paramounts without encoders deliver 5- to 10-minute unguided exposures, many up to 20 minutes, and direct-drive models are better still.

Industrial Control System: 3-Axis Stability with Ethernet Control

The Taurus 500 is governed by a three-axis industrial direct-drive motor controller housed within the mount's pedestal. The controller has a configurable 10-20A, 20 kHz control algorithm rate. It also supports an optional third axis for the Software Bisque instrument rotator.

Communication with the mount is handled via a standard Ethernet connection, providing robust and reliable control from a host computer. For users who wish to bypass TheSky, the controller supports direct communication using the ACSPL+ command set, allowing for custom integration into existing observatory control systems.

TheSky Universal Bundle: A Complete Multi-OS Observatory Suite

Every Paramount Taurus 500 includes TheSky Universal bundle, a professional-grade software suite for observatory control. The bundle features TheSky Professional, TPoint, Cameras+, Domes, Multi-OS+, and the Weather module. The Satellites module is also included for ephemeris-based satellite tracking.

A critical feature of this software is its cross-platform support. The entire suite runs natively on Windows, macOS, and Linux (x86_64 and ARM64), with an identical interface and feature set across all operating systems. The included license permits installation on up to six computers, providing complete flexibility for your observatory and data processing workflow. A physical USB security key is required for TheSky to operate with the mount.

A 400 lb. Instrument Capacity with Integrated Balancing

The Taurus 500 is engineered to carry a total instrument capacity of 400 lb. (180 kg). The rigid fork design and massive 10-inch hour angle and 8-inch declination bearings provide the stability necessary for such heavy payloads. Mounting an OTA is facilitated by the optional Software Bisque Scope Rail System, which allows instruments to be moved fore and aft for precise balancing along the optical axis.

To correct for imbalances caused by asymmetrical instrument packages, the mount includes a tine counterweight system. The support tine (the non-drive side) features an attachment plate for counterweights to offset the heavier drive tine and any off-center equipment, so the system can be balanced for smooth tracking.

Installation & Alignment: A 5-Component Assembly with a 0-58° Latitude Range

Despite its size, the Taurus 500 is designed for manageable assembly by a two-person team. The mount breaks down into five primary components, each weighing under 100 pounds: the wedge, the HA assembly, the fork center, the drive tine, and the support tine. The Taurus pedestal houses the control electronics and provides the mounting base.

Polar alignment is achieved via the integrated equatorial wedge, which offers a latitude range from 0° to 58°. A ratcheting mechanism allows for coarse latitude adjustments in six-degree increments, while a fine-threaded adjuster provides precise control. Azimuth can be adjusted by ±2.5°. Once mechanically aligned, TheSky's Accurate Polar Alignment routine helps align the mount precisely to the refracted pole.

Power & Thermal Management: 110-240V AC Operation

The Paramount Taurus 500 operates on a standard 110-240V AC power source, with a maximum draw of 15A. An internal power supply provides the necessary DC voltage for the control system and motors. All electronics and cabling are routed internally through the mount, with conduits available for additional user-supplied cables.

To ensure reliable operation in a wide range of climates, the control system enclosure includes both a heater and cooling fans. The thermostat turns the heater on at 5 °C or lower and off above 10 °C. One of the two pedestal fans is connected at the factory; above about 30 °C the second fan can be connected for more airflow.

A 400 lb. Machined Aluminum Platform

The total weight of the Paramount Taurus 500 mount is approximately 400 lb. (180 kg). The majority of the mount's structure is machined from 6061 and 6063-grade aluminum, and bisque.com describes the mount base as powder-coated steel.