The GM4000HPS II German Equatorial Go-To Mount is built for permanent observatory installation. The HPS (High Precision and Speed) absolute encoders and fully integrated standalone control system deliver an unmatched level of accuracy and performance. Ideally suited as an un-guided imaging platform for fully instrumented refractors up to 12", Newtonians up to 16", and Cassegrains up to 24" (eg CDK 24).
With a conservative usable instrument capacity of 330 lbs, the GM4000HPS delivers rigidity, accuracy, and performance exceeding all other mounts in its class. The state of the art bronze worm gear drive system and well-engineered axis mechanics provide high rigidity, long term reliability and life, along with the phenomenal HPS tracking and pointing precision demanded by the most discriminating imagers. The build quality, precision of the machining, and the level of fit and finish are truly exceptional.
A large range of piers, mounting plates, dovetails, and accessories are available from 10Micron and Baader Planetarium.
What is HPS?
HPS means “High Precision and Speed” and is the name for the series of astronomical mounts by 10micron. The HPS system features two high-precision absolute encoders that are integrated directly into each axis to ensure unprecedented pointing and tracking accuracy. High performance servo motors and drivers enable high speed pointing. The HPS system was architected from the ground-up for precision pointing and control. The encoders were not simply added onto an existing mount and its control system. The tightly integrated hardware and on-board firmware architecture results in total system response and accuracy that are superior to mount systems that require an external PC for pointing modelling and control. Simply put - the HPS system results in improved pointing and significantly lower RMS tracking errors than competing mounts.
This radical performance improvement over previous technology enables a radical change in the workflow of observers and astroimagers. In the vast majority of applications, including long exposure deep-sky imaging, the need for autoguiding is eliminated. The pointing accuracy allows you to be confident that, once the mount is properly setup, objects will be centered in the smallest field of view, even with a mobile setup on a remote meadow in the mountains. Furthermore, the internal electronics allows the mount to do almost everything without the need for an external PC.
The absolute encoders provide high-accuracy, sub-arcsecond feedback to the motion of the mount. The absolute encoders render the axes “live” and free to react also to any external forces like wind and vibrations or accidental contact. Furthermore, this feedback is provided regardless of any zeroing or homing procedure.
This means that the electronics will always know the position of the mount. You may move the mount around with the clutches unlocked and the electronics powered off, lock the clutches in any position and switch on the mount: the electronics will know where the telescope is looking. You may effectively use the mount as a Dobsonian telescope with manual pointing, retaining the full, sub- arcsecond accuracy of the encoders. This equates to ease of use when operating in the field, since the setup procedure is much faster.
HPS enables the GM4000HPS is able to deliver <1 arcsec (peak-peak) tracking and 20 arcsec pointing accuracy. The accuracy and response of the HPS system gives the imager a powerful tool that enables un-guided long exposure images. Never before has this level of accuracy been available to the amateur, and at such affordable prices.
With regard to the right ascension axis, virtually all the mechanical error from the reduction gearing is eliminated. Not only the so-called “Periodic Error”, which includes the periodic irregularities due to imperfection in the manufacturing and assembling of the worm, but also the non-periodic errors due to imperfections in the wormwheel, bearings, belts and other mechanical elements.
With regard to the declination axis, it may seem that the encoder system is less important, since there is no sidereal tracking motion. The reality is that the declination axis is critical to sidereal tracking. If you want to compensate for refraction, telescope, flexure and so on, you will have to move the declination axis at very small speeds in very small amounts. Furthermore, while the right ascension axis works always at the same speed (plus or minus small corrections), the declination axis works always at near-zero speeds, with the occasional inversion of the direction of motion. This means that mechanical backlash, belt flexure and friction forces show in the declination axis, and you can’t count on any “Periodic Error Correction” to compensate for them. Tricks for minimizing the effect of these forces in traditional mounts require having very small preload on the worm, with the risk of uncontrolled motion when the telescope is subjected to even small external forces, because of the disengaging of the worm from the wormwheel; painstakingly calibrating software backlash compensation procedures; manually adjusting the meshing of gears. Or, maybe, introducing intentionally small alignment errors, to force autoguide corrections always in the same direction. So, having an encoder mounted directly on-axis is at least as important in declination as in right ascension.
The task of accurately pointing and tracking astronomical objects requires that the mount fully model all aspects of location, sky, and mechanics.
- Modelling the orientation of the mount with respect to Earth
- Modelling the orientation of the telescope with respect to the mount.
- Modelling the errors of the mechanical system with respect to an “ideal” one.
- Modelling the influence of the atmosphere on the path of light rays.
- Modelling the orientation of Earth.
- Modelling the motion of astronomical objects themselves.
In order to obtain the sub-arcsecond tracking accuracy of the HPS mounts, all of this must be taken into consideration. Furthermore, many “subtle” effects begin to show, and they need special attention. The HPS system takes modelling to another level than other mounts that use external PC pointing models. HPS performs the modelling and stores the model in the internal control system of the mount. In this way, the control system is able to provide rapid response and control of the mount, as well as for standalone operation.
The quick alignment routines and highly reliable standalone operation enable convenient and highly reliable setup for remote fully automated installations (NO PC required for mount alignment and control!).
The sophisticated control system and belt driven brushless F.I.S. AC servomotors deliver whisper-quiet fast slews with high pointing precision and tracking. The slew speed of up to 8 degrees/second is 2x the speed of most other GoTo mounts, enabling lightning fast slews and precision tracking of satellites (the satellite tracking function is already embedded into the control system). Furthermore, it helps to reduce loss of time in research application, increasing the amount of data that can be obtained in the often short observing nights.
The integrated control system also includes stand-alone operation through use of its ergonomic handpad, freeing the user from the requirement of having to always use an auxiliary PC to control the instrument. Through the handpad, the stand-alone user can access all of the many integrated functions including; full Object Database, High-Precision Polar Alignment, Orthogonality Correction, Periodic Error Correction, as well as a Multi-Star Alignment which models and compensates for telescope pointing errors. A GPS module is optionally available.
Each mount is thoroughly tested as a system to ensure that its performance, accuracy, and quality meet the 10 Micron standards. The engineering, design, and build quality of the GM4000HPS are unlike any other mounting in the world. The precision of the machining, quality of the components, and the level of fit and finish are breathtaking.
Why Not Autoguding?
Autoguiding seems simpler… for the mount manufacturer. For the user, autoguiding means additional trouble. In case you use an external guider scope, it means that you can’t compensate for all flexures between the two instruments. And, you have additional, heavy equipment. In the case where you use a dedicated guider camera, it means additional cabling, software installation and setup. In any case, it means additional trouble searching for suitable guide stars, looking for customized guiding software parameters, calibration, and glitches between the guider/mount/PC. HPS mounts can be aligned to bright stars during twilight, then every second of darkness can be used for imaging. Furthermore, autoguiding is not always possible. The typical situation is imaging a faint, fast-moving comet. Anyway, if you still want / need autoguiding, HPS mounts provide a standard ST4 port, as well as all the usual settings and controls for use by remote software.
All the features and performance of the 10Micron mounts would be worthless without matching quality. Each mount is thoroughly tested as a system to ensure that its performance, accuracy, and quality meet the 10 Micron standards. The engineering, design, and build quality of the GM4000HPS are truly world-class. The precision of the machining, quality of the components, and the level of fit and finish are exceptional and will satisfy the most critical user.
The HPS mounts were developed at 10Micron by a team of professional engineers with decades of experience in the design and in-house production of precision machinery for the machine tool industry in Europe. Each mounting is fully machined and assembled in-house at 10Micron's production facility in Italy. As machining experts, 10Micron is able to consistently produce a level of precision that is unique in astronomy.
In order to deliver the absolute highest accuracy and rigidity, in every mount produced, all critical parts of the mounting are machined as single pieces from solid plate or bar stock. No screwed-together or crude cast structures are used. The quality of machining and fabrication is evident in every part of the mounting, inside and out. Part-to-part fit and matching is superb and machined edges are fully radiused and blended for a functional and aesthetically pleasing look.
Fit and Finish:
The fit and finish of every part is given close scrutiny. All external surfaces of the mounts are hand finished through a time consuming process to eliminate tooling marks, swirls, and sharp edges. This process results in an exquisite satin finish that gives a beautiful and consistent look part-to-part, and serves to hide any smudges or marks that inevitably result from normal use and handling.
After surface finishing, the complete set of parts are hard anodized together in one batch, in order to provide high consistency of color part-to-part. The hardness of the anodized surface resists wear and chipping, unlike paint. The end result of all this careful finishing is a mounting that is as breathtaking to look at as it is to use.
Mount capacity is often misunderstood, and typically implied to be primarily a function of gear size. While most mountings (even small ones) can physically support and drive very large loads without failure, capacity is determined first and foremost by the rigidity of a mounting. Rigidity is simply the 'springiness' that you feel (and see at the eyepiece) when pressing on the telescope or against its focuser. It is easy to quickly judge the rigidity of a mounting simply by pressing against the telescope's focuser in each direction and noting how much a star shifts in the eyepiece.
Unfortunately, it is not really possible to simply compare mountings on the basis of gear size, physical size, weight, or appearance. Many unseen elements are primary contributors to a mount's performance. The primary elements that contribute to rigidity (capacity) are the stiffness of the two axes and their bearing support system, the stiffness of the drive system (axis torsion) and the rigidity of the supporting structure of the mount itself (and of course the supporting pier/tripod). Like a system of springs, the rigidity of a mount is the result of all these factors combined, and is often dominated by its weakest element.
An often hidden or overlooked aspect of good mount design is the design and construction of the RA and DEC axes. Much of the flex felt in commercial mountings is due to inadequate axis stiffness. This can be caused by poor bearing configuration, long overhangs or cantilevering of the axis, or poor material choices. Even seemingly large, massive, and impressive looking mountings often suffer from surprisingly soft axes due to poor design and implementation.
10Micron uses large diameter thick wall alloy steel for both the RA and DEC axes. Steel is 3 times stiffer than aluminum (which is often chosen for its lower weight). Both axes are supported by extra-large diameter preloaded conical tapered roller bearings, which give much greater stiffness and bearing capacity than ball bearings. The primary loads are closely coupled to the bearings to minimize flexure. The result is an uncommonly high axis stiffness that minimizes flex in all directions.
The key structural elements of the 10Micron mounts (RA and DEC housings, Altitude Support Plates) and their attachments have been structurally engineered to provide high stiffness. These key parts are precision machined as single pieces from solid bar or plate stock. The altitude support plates are one piece gusseted and physically well-coupled to the oversized RA housing through precisely mating surfaces and 6-point clamping.
No modern GoTo mount would be complete without a highly accurate and reliable drive system. GoTo systems demand a difficult mix of high speed and high accuracy - over a long life of night-after-night use in automated installations. To meet these tough demands, 10Micron chose the ideal material pairing of a special gear Bronze for the worm wheel, and a carefully matched alloy steel for the worm (not stainless steel, which has inferior properties for use in a worm). While these materials add significant cost compared to the aluminum gears found on many other commercial mounts, the outstanding friction and wear properties of the gears are critical to delivering the ultra-high speed and low error over the life of the mounting.
With the superior drive properties that come with Bronze also comes weight. Rather than simply using lower cost aluminum for the gears to shave weight, both the Dec and RA gears incorporate central hubs of aluminum, and only the outer periphery is made from Bronze. This combination takes more cost and effort, but gives the best of both worlds - the low weight of aluminum, with the superior drive and long wear properties of Bronze.
The bronze worm wheel and hardened steel worm are produced using the latest tooling and machinery. Worms are evaluated using precision helical path analyzers to ensure a consistent and smooth low native periodic error. The HPS absolute encoders are integrated by the factory (not an add-on), precisely centered and calibrated uniquely for each mount. After assembly, each mounting is analyzed as a complete system using even higher precision encoders to ensure the HPS tracking accuracy meets the 10Micron standards.
A unique zero-cogging kevlar belt reduction drive results in whisper quiet operation with virtually zero motor backlash. Gone are the grinding and whirring noises of the gear drives used in most other telescope mountings. Onlookers at NEAF were often seen pressing their ears close to the mountings just to see if they could hear the motors.
The spring loaded anti-backlash mechanism of the worm drives deliver near-zero backlash at the telescope. The design of the worm support structure and large diameter precision tapered conical worm bearings result in a drive system with uncommon torsional rigidity, making the 10Micron mounts particularly adept at handling large refractors. No wonder that TEC (Telescope Engineering Company) chose the GM2000 to demonstrate their long 8" f/8 refractors at star parties and shows.
The end result of all this careful engineering and execution are mounts that exceed expectations for rigidity and capacity.
The electronics are housed in a separate control box which is easily removable. The connections to the motors and hand pad feature security lock screws.
The HPS control system also enables stand-alone operation through use of its ergonomic handpad, freeing the user from the requirement of having to always use an auxiliary PC to control the instrument. Through the handpad, the stand-alone user can access all of the many integrated functions including; full Object Database, High-Precision Polar Alignment, Orthogonality Correction, Periodic Error Correction, as well as a Multi-Star Alignment which models and compensates for telescope pointing errors. A GPS module is optionally available.
New generation AC servo brushless motors with fully integrated servomotor system: F.I.S. is a new technology in the field of total electronic integration for control, power, encoder and communications, all built-in to the motor's body.
Sidereal, solar, lunar, custom, land mode.
It is possible to set different speeds for the two axes’ for comet or satellite tracking (satellite tracking function included as standard feature of the HPS system).
Internal, complete catalogues: M, NGC, IC, PGC, UGC, SAO, BSC, HIP, HD, PPM, ADS, GCVS, PLANETS, ASTEROIDS, COMETS...all in memory.
Operator interface: (No External PC Required!)
Handpad Controller: the control system uses an ergonomic hand terminal to pilot the mount, to slew to objects, to set parameters, to sync a star, to change slew or guide speeds. Includes a numerical keypad with rapid search keys, and a red 2x16 character industrial illuminated display that operates over a wide range of ambient temperatures: +40°C / –20°C (-4°F). The extended brightness range accommodates both daylight and night time viewing. It’s a total communication interface between the mount and the operator. Handpad includes a removable protective cover.
The controller includes a port for a GPS module (optional accessory). The system automatically links and adjusts itself to the GPS network date, time, and position.
Connection to PC:
The system can be controlled using the most common software packages by means of the LX200 protocol (same as Meade 16’’GPS), AP GTO protocol, or the proprietary 10Micron ASCOM (ie, prgrams such as The Sky, MaximDL, Desktop Universe, and Perseus).
Furthermore, dedicated software (also included with the mount) can be used to create a “virtual hand pad” which exactly replicates the functions of the physical hand pad, allowing full remote access to all hand pad functions. The RS-232 port can also be used to control an external dome. This flexibility makes the GM4000HPS an ideal mount for observatories and remote automated observing sites.
Remote Operation and Connectivity:
The HPS mounts provide a great deal of connecting options. While you may choose the traditional RS-232 connection to control the electronics up to 15 meters (50 ft) from an external PC, today you may prefer to dedicate it to directly controlling a computerized dome. The firmware will provide all the relevant computations even for mounts mounted off-center and instruments mounted with offset. The GPS port doubles as an additional RS-232 port, if you don’t use the GPS.
But, the best way of connecting the mount to your PC is using the LAN connection, via TCP/IP, or the Wireless connection. The mount can connect to an existing WLAN, or it can be used as an hotspot to which your PC, tablet or smartphone can connect. The mount can be controlled up to 100 meters (325 ft) from the PC with the LAN (Ethernet) connection using the included “virtual key pad” QCI software or with special custom made software using the 3490 port. The system can be powered on /off remotely using an external switch.
The system can be controlled through the LAN port, even remotely, by means of an Ethernet host server or by wireless links and Internet. Via LAN, the RS232 port can also be used to remotely control an external dome, without the need for a dedicated external PC.
The LAN connection offers superior high-voltage tolerance with respect to the typical RS-232 connection; this is even better with the WLAN which is… wireless. In case of remote observatories, which are subject to lightning, this may make the difference between healthy electronics and a fried one!
The mount supports up to ten simultaneous TCP/IP connections, so you can use different software, and also different devices, at the same time. 10micron provides an ASCOM driver for Windows, but if you want to implement your own control system, we provide the command set that can be used both on the RS-232, LAN and WLAN connections. The command set is largely LX200 compatible, but includes many more functions and operating modes. In remote operation, you will appreciate also the additional security provided by the absolute encoders: in no case you will lose your alignment, even in case of slipping clutches.
Single port standard SBIG and Starlight X-press interface: 6 contact standard phone jack (TTL). It is possible to autoguide using the ST4-compatible port or through the serial/Ethernet connection, with a guide rate configurable from 0.1x to 1x. The guide rate can be automatically corrected for the declination of the target, so that there is no need to recalibrate the autoguide when observing at different declinations.
HPS has built-in motor encoders inside the motors which obtain a final resolution of 0.1 arcsec (GM4000) – 0.5 arcsec (GM2000) (minimum move size). The motor encoders are used together by the servo system along with the precision HPS absolute encoders to achieve the phenomenal tracking, pointing, and speed. Encoders maintain the position reference of the mount at every given moment, also after the system shutdown (park). Every time the system is switched on, it automatically initialize the motor’s soft homing of itself. Furthermore, the system can do a Hard Homing (with sensors) - GM4000 only.
NO periodic error correction is necessary with the HPS system. Periodic error is less than 0.5 arcsec native, no PEC needed.
The system takes into account the number of turns automatically and/or manually made by the axis and prevents their wrapping, de-winding them every time that the system slews to a new object.
The system automatically determines the ideal pointing position to avoid collision of the telescope with the base of the pier or tripod through the use of user-configurable parameters. The system allows pointing to an object up to 15 degrees past the meridian. This allows the user to point the telescope on the ‘wrong side of the meridian’ so that a meridian flip is not required in the middle of a long imaging session. The angle that the system will continue to track an object is user configurable up to a maximum of 30 degrees past the meridian. In this way any object can be tracked for at least four hours. The system may be set to permit pointing to objects up to 5 degrees below the horizon. Note: all limits are user configurable from 1° to max.
Mount alignment functions:
Alignment of the polar axis with Polaris: this procedure uses a star and Polaris to align the polar axis.
- Two star calibration: when this procedure is performed, the mount uses the two stars to calculate the polar axis error and compensate for it.
- Calibration with additional stars: Refine 2-stars, up to 100 stars! This function builds an internal pointing model for more precise pointing and compensation for telescope mis-alignments (including non-orthogonality), allowing for the correction of the classical polar alignment and conic errors, and also of the most important flexure terms of the optical tube. In this way it is possible to obtain pointing accuracies of the order of 20 arcseconds RMS. The same model can be used in order to obtain the maximum tracking accuracy, compensating also for the atmospheric refraction (depending on the local atmospheric pressure and temperature).
- No PC required!
- 3-stars alignment: direct 3-star alignment (used to find some stars in a limited viewable-area sky condition)
Alignment of the polar axis without Polaris:
The “Polar Align” function is used to accurately align (to under 1 arcmin) the polar axis of the mount to the celestial pole without use of a polar finderscope. Polaris is not required to be visible.
Orthogonality error correction:
The” Ortho Align” function is used to help you to correct the mechanical orthogonality error of the instrument.
This function shows the alignment information. A short text will appear and tell you the type of alignment used (no alignment, 2‑stars, 3 or more stars if you have used additional stars) If a 2‑stars 3 or more alignment has been completed, the system shows an estimation of the polar axis position error:
- An estimation of the polar axis position error and its position angle relative to the celestial pole plus information how to correct errors operating directly on azimuth and altitude knobs.
- An estimation of the orthogonality error between the optical axis and the declination axis. This function is useful to verify that the telescope is really orthogonal to the declination axis.
- A list of the aligned stars and date of the saved alignment.
Automatic tracking “follow objects”:
With this function, the system will automatically set a custom tracking rate in both axes each time it slews to an object, in order to follow it through the stars. Solar system objects can be tracked so that their motion is compensated with respect to the stars. You may load orbital elements of comets, asteroids and even artificial satellites into the mount, so that these objects can be tracked directly using the hand pad (without any external PC).
Visible Object filter: (comets and asteroids)
When you activate this function, the system will ask to you to define a magnitude limit in order to create the observable objects list.
Multiple Instrument Support:
The HPS mounts feature a rich system of accessories for mounting various instruments. Even multiple instruments can be mounted on a single mount, in order to have the right imaging equipment always ready. Since the pointing and tracking model depends on the specific instrument (the flexure is different), the mount allows for different models, one for each instrument, that can be saved in the internal memory and reloaded when required.
The mount can be switched on and off using the dedicated connector on the control box panel. You can use the electronic balance functions in order to balance your instrument without unlocking the clutches. The mount can be parked in different user-defined positions. An external dome can be controlled directly using the RS-232 serial port, avoiding the need of using a dedicated external PC. Once configured with your instrument parameters, the firmware is able to make all the calculations required for positioning the dome slit in front of your optical tube, for almost all instrument configurations.
|Axes Diameters, RA and DEC||RA 3.35" (85mm) Diameter, DEC 3.2" (80mm)|
|Material||Alloy Steel (3X stiffness of Aluminum)|
|Bearings||Tapered Roller Bearings, Preloaded|
|Worm Wheel, RA and DEC|