|HPS (High Precision and Speed) is the
total system integration of special high resolution absolute encoders
with the sophisticated QCI control system and 10Micron's precision worm
drive mechanics, delivering <1arcsec p-p precision and high speed
(20deg/sec), at a price previously unachievable by any other technology.
With the integration of 10Micron's new HPS System into the GM4000HPS,
advanced amateurs and professionals now have the ultimate observatory
platform to use for acquiring long exposure unguided images with very
large instruments. The high-resolution absolute encoders are
permanently attached and calibrated to each axis, not simply as an
add-on to an existing system, but fully integrated mechanically and
electrically into the control system. The HPS encoders know their
absolute position, even after power down. Factory inspection and
calibration of each mounting ensures that the phenomenal accuracy is
maintained throughout the full rotation of each axis.
HPS Tracking Curve (obtained from a GM2000HPS)
Drive System Comparisons
When selecting a
mount and considering different drive systems, it is important to
consider the tradeoffs associated with each approach. Traditional
motor- encoded precision worm gear driven mountings have predominated
the amateur market for many years, providing good value and accuracy
(typically ~8 arcsec p-p). Open-Loop Periodic Error Correction can
reduce this by almost a factor of two in the best situations.
However, the accuracy of even the best mountings still falls short and
requires autoguiding or very short exposures to prevent trailing.
Recently, a new
Direct-Drive system has arrived on the amateur mounting market.
These systems incorporate high resolution encoders on each axis and
directly drive their axis' without the use of gears (the axis itself
becomes the motor, requiring high currents to provide sufficient torque
to drive and hold position). While this approach has some
advantages, in practice, it also has disadvantages to overcome.
We think the
hybrid 10Micron HPS System provides the best overall solution, providing
extreme accuracy and speed, along with the portability, quick setup,
reliability, and robustness of a conventional worm driven mounting.
If you are
comparing mounts and their drive systems, we suggest you click on the
link below for an overview of the different drive types and their
No separate computer needed, even
in remote automated installations. The GM4000HPS incorporates a full
featured and flexible GoTo control system that provides both total
standalone operation as well as full remote operation of all mount
functions. The integrated control system utilizes a powerful AMD
microprocessor and is
housed in an on-board fan cooled enclosure. Its internal LINUX
based software is fully upgradeable and future-proof, avoiding the
constraints and limitations common with hardware based
provides a large suite of object databases for powerful and convenient
location of objects and is as easy to use for casual use as it is for
serious work. The full function handpad incorporates an industrial
wide-temperature capable red backlit display and illuminated keypad to provide
reliable access to all functions through a convenient menu and button
Notable functions include
accurate polar alignment routines and a sophisticated internal pointing
model that utilizes up to 25 stars to achieve pointing accuracies of
under 15". Full featured and robust software interfaces include
LX200 protocol (same as Meade 16’’GPS), AP GTO protocol,
and ASCOM (via LX200). QCI also includes a full suite of hardware interfaces
for remote automated operation - including integrated LAN for remote
connection without a PC! For more details
on this powerful integrated control system,
click on this QCI Control System link.
In order to provide rapid
unattended error recovery, the GM4000 has been equipped with precision
homing sensors in both Dec and RA axes. In the event of power
loss or other unforeseen occurrences, the system can be quickly and accurately re-calibrated by
performing a home command. Software slew limits allow
restriction to prevent collisions with observatory structures, and
internal mechanical stops prevent inadvertent over travel and cord-wrap.
The amount if
instrumentation needed in many applications places large demands on the
amount of cabling required. As a result, robust and reliable cable
management becomes a critical aspect of any observatory mounting.
The GM4000 has been designed to enable the cleanest cable routing
possible - through the mount itself. The Dec and RA axis include
large 60mm (2.4") diameter pass-through openings which will allow
routing of cables with large connectors.
Even the best mount and drive
systems exhibit sub arc-minute (repeatable) pointing errors. These
small errors can be compensated for by software pointing models (such as
Tpoint, or the built-in multi star alignment modeling of the QCI + HPS control system).
In order to provide software pointing accuracy at this demanding level,
it is necessary to maintain the relationship of the drive gears and the
mount axes. In the case of a mount with clutches (like the
GM2000HPS), it is possible to change this relationship by manually moving
the mount and causing the clutches to slip. The choice to add clutches has many
benefits for portable use. The GM4000HPS foregoes
the use of clutches, in order to enable the very highest level of
software pointing accuracy. In case of encountering fixed
objects (observatory roof, pier, etc), the QCI control system is
designed to limit the amount of force applied by the motors, in order to
minimize any damage to equipment.
Both RA and Dec worms of the
GM4000HPS are user disengage-able to facilitate balancing of instruments.
Professional Capacity and Performance
capacity is often misunderstood, and many manufacturers imply this to
simply be 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 is felt when
pressing on the telescope or against its focuser. It is quite easy
to 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 for a given force. Professional applications demand the
ability to handle large instrument loads with minimal mounting
deflection in order to maximize the inherent pointing accuracy of the
system and reduce sensitivity to wind and other externally induced
forces/vibrations. While software pointing routines are able to compensate
for repeatable deformations, only through minimizing the mount's
inherent flexure can total errors be reduced and superior accuracy
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 (torsion/twist) and the rigidity of the
supporting structure of the mount itself (of course, rigidity of the
permanent pier is an additional significant factor). Like a system of
springs, the rigidity of a mount is the result of all these factors
combined, and is often limited by its weakest element. Therefore,
it is important to understand the key elements that go into a mount's
design and fabrication.
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 cantilevering of
the axis, or inferior construction and materials. Even some seemingly large and
impressive looking mountings suffer from surprisingly soft axes
due to poor design and execution.
The nature of fork mountings
places large loads on the RA axis. The stiffness of the fork
itself is a significant weak link in this type of mounting, requiring significantly more
structure and mass to reduce the flexure. For this reason, it is
very difficult for any fork mount to achieve the rigidity and pointing
accuracy of a german equatorial. In order to achieve comparable
performance, an equivalent fork mount can require several times the mass and
The GM4000 utilizes massive
85mm (3.4") diameter
thick-wall steel for the RA axis and 80mm (3.2") for the Dec axis. Steel is 3 times
stiffer than aluminum (which is often chosen for its lower weight).
Both axes are supported by extra-large diameter (130mm) preloaded conical
tapered roller bearings, which give much greater stiffness and bearing
capacity than ball bearings. The primary loads have been carefully designed
to be closely coupled
to the bearings. The result is an extremely high axis stiffness that minimizes flex in all directions.
key structural elements of the GM4000 (RA and DEC housings, Altitude
Support Plates) and their attachments have been structurally engineered
for rigidity. These key parts are precision machined
as single pieces from solid bar or plate stock, in order to deliver the
highest rigidity and accuracy possible. The altitude support plates are
machined from 38mm (1.5")
plate and are rigidly coupled to the oversized
(7.25") diameter RA housing through precisely mating surfaces and 6-point
clamping. In order to provide the absolute maximum rigidity
and minimize vibration and flexure,
all critical structural parts have been left in their solid state with
NO internal pocketing. This avoids the structural weakening that
occurs in all mounts that utilize pocketing to reduce weight for
Drive System: An often
overlooked aspect of mount design is the structural performance of the
worm drive. Simply going to larger worm wheel sizes can not fully make
up for a weak worm drive. All torsional (twisting) loads placed on the axes of a
worm-driven telescope mounting must be reacted through the worm itself.
The size and configuration of the worm bearings and the worm mounting
play an important role in determining torsional rigidity. The
GM4000 worm support
structure has been designed to minimize flexure of the bearing mounts as
well as the anti-backlash pivot. The 32mm diameter steel worm is
mounted with oversized precision tapered conical worm bearings
which transmit the worm thrust loads with less axial flex than ball
bearings. These aspects combine to make the drive system of the
GM4000 torsionally stiff and capable of handling physically large
instruments without excessive flexure and vibration.
The end result of all this
careful engineering and execution is a professional mount that exceeds expectations
for rigidity and capacity.
The GM4000HPS makes use of new
technology brushless AC Servomotors to deliver high torque and accuracy,
along with long life and freedom from motor brush maintenance.
These motors incorporate a new approach in servomotor design - F.I.S.
The Fully Integrated Servomotors incorporate the critical drive control
and encoder electronics into the motors themselves. This enables
the unique mix of performance and high accuracy inherent in the GM4000HPS
The spring loaded
anti-backlash mechanism of the GM4000HPS worm drive delivers near zero
backlash at the telescope. A unique zero-cogging kevlar belt
final reduction drive results in whisper quiet operation with virtually zero
motor backlash. Gone are the grinding and whirring noises of the
all-gear drives used in most other telescope mountings. Onlookers at
NEAF 2007 were often seen pressing their ears close to the mountings
just to see if they could hear the motors running.
No professional mount would be
complete without a highly accurate and reliable drive system.
Automated mountings 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
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 commercial mounts, the superior friction and long wear
properties of the GM4000 gears are critical to delivering the high speed,
and low error over the life of the mounting.
The bronze worm wheel and
hardened steel worm are produced using the latest state-of-the-art
tooling and machinery. Worms are evaluated using precision helical
path analyzers to ensure a consistent and smooth low periodic error. 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.
GM4000 was developed at 10Micron by a team of professional engineers
with decades of experience in the design and in-house production of
astronomical telescope mountings as well as precision turnkey machinery for the machine tool industry in Europe.
Each mounting is fully machined, inspected, and assembled in-house at
10Micron's production facility in Italy. As machining and tooling
experts, 10Micron is able to consistently produce a level of precision
that is unique in astronomical mountings.
order to deliver the absolute highest accuracy and rigidity, with
perfect consistency mount-to-mount, all critical parts of the mounting are machined as
single pieces from solid plate or bar stock. No welded,
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.
and finish of every part is given close scrutiny. Just like its
smaller sibling, all external surfaces of the GM4000 are hand finished
through a time consuming buffing process to eliminate tooling marks,
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.
surface finishing, the complete set of GM4000 parts are 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 impressive to look at as it is in
GM4000 is available in attractive metallic Gray.