MACH1GTO MANUAL

Why a Mach1GTO?

Design Goals:

This is the first, compact, light-weight mounting that was designed for utmost portability while maintaining extreme rigidity and excellent tracking accuracy. No shortcuts were taken to achieve these goals. From the highly-accurate fine-pitch gearbox to the precision-machine tool bearings, to the innovative worm wheel and clutch design, this mount represents a new approach to this vital part of the overall imaging train.

The advent of modern CCD cameras and telescopes with high-resolution optics has placed greater demands on the ability of mountings to do their part to achieve precision tracking and guiding. At the same time, the mounting should be easy to use with adjustments and setups that are straight-forward and accurate. We have done everything possible to eliminate the frustrations and limitations inherent in a lesser mounting and so put the fun back into the hobby of amateur astronomy.

Principal features of the Mach1GTO Equatorial Mount:

The heart of this mount is a precision gearbox using high-quality fine-pitch gears, coupled to a highly accurate worm and worm wheel. These parts are manufactured and assembled at our facility and individually tested to meet or exceed our periodic error spec of 7 arc seconds (+/- 3.5 arc sec.). The servo drive uses the same Swiss motors found on our larger mounts. They are oversized and easily drive the mount at full slew speeds in below-freezing temperatures. The brass worm is machined to have a true helical thread, clean and accurate for minimum periodic error. The PE is smoothly variant with extremely low ripple or moment to moment error.
Dennis di Cicco had this to say about the Mach1GTO's performance:

"The mount’s tracking and Go To pointing are among the most accurate I’ve ever tested. At the end of each night I’d park the scope and turn off the power. Whether an hour, day, or week elapsed until I’d power up the mount again and “resume from park,” it would have perfect sync with the sky — even to the point of “hiding” stars behind my finderscope’s crosshairs when I’d check the alignment by slewing to them in a bright twilight sky . . .

Such Go To pointing precision comes in handy when shooting photographic mosaics, making a sequence of deep exposures of the same field on multiple nights, or hunting difficult targets by eye."

Periodic error corrections for each individual mount are optimized during extensive testing, which results in excellent performance right out of the box.
The spec of 7 arc seconds (+/- 3.5 arc sec.) is the maximum native mechanical error inherent in the mount's RA axis WITHOUT any software correction being introduced. However, in the process of testing the RA axis with a special version of Ray Gralak's PEMPro developed specifically for our test equipment, we generate a unique PE curve that we can then program into each individual mount. Simply use the Keypad to turn PE Correction "on," and you will see results even better than our published 7 arc second spec! PEMPro (available as an option) is a very powerful program that allows the user to characterize the periodic error to a high degree of accuracy and to reduce it dramatically for long unguided exposures. It is especially useful for this mount since the average worm rotation error is already quite low, and the short term ripple error is almost nonexistent. You may wish to consider PEMPro, especially down the road as your worm gear runs in. Depending on usage, re-measuring error and re-loading periodic error correction from one to four times a year is a good practice, especially if you do some unguided images from time to time.

Although the mounting is very light for its size and load rating, it has been machined out of solid metal to withstand the high axial and thrust loads that a medium-sized telescope places on the mount under real-world observing conditions.
It is solidly built and will withstand gusting winds without excessive shake or vibration. We used high-quality machine tool bearings, rated in excess of 400 lb. static and dynamic load, on the main axis shafts. Both worm wheels turn smoothly with no runout throughout their 360 degree range. To quote Dennis di Cicco's review again:

"Extremely rigid for its size and weight"

Route your cables through the mount for tangle-free operation and peace of mind.
Both axes have 2 inch clearance holes down the center with no shafts protruding into the holes so that wires from CCD cameras and accessories can be inserted from the bottom of the RA axis to emerge from the top of the Dec axis where cable channels have been machined to allow the cables to be routed under the mounting plates. There is no restriction of rotation with the wires inserted - one can rotate both axes more than 360 degrees without catching the wires on any parts.

The mount comes with our superb GTO Servo Drive and Keypad package and PulseGuide software for maximum performance during image acquisition.
PulseGuide allows you to accurately track asteroids, comets and the Moon, which move relative to the stars. PulseGuide is also the preferred method for initializing and parking the mount when used in remote operations where the keypad is not in use. More information below ...

The altitude adjustment allows the mount to be used from zero to about 70 degrees latitude, from the top of Finland to the coast of the Antarctica.
There is a scale on the side for approximate adjustment in the field and the mount has a bubble level and a compass in the base. The azimuth adjustment is approximately +/- 12.5 degrees (25 deg. overall).

If you already own our previous 400 or 600E German Equatorials, you will be pleased to learn that many of the same accessories can be used with the Mach1GTO.
These include counterweights, mounting plates, polar alignment scope (PASILL4 or the prior PASILL3 model are preferred), piers and tripods.

Versatility

Portable Enough for Airline Travel
Transport this rigid observing platform to your dream destination. RA and Dec axes split easily into two pieces, allowing the entire mount to fit into a single rugged carry-on case that will roll easily through airports or to your car. Please note that airline carry-on requirements may change over time or vary from one airline to another. We suggest that you confirm all requirements and restrictions before traveling!

Sophisticated Enough for Remote Operation
The Mach1GTO was designed from the ground up to take full advantage of the latest electronics. The integral internal cable channel allows multiple electronic devices to be used without the usual tangled cable nightmare. The Mach1GTO uses the same servo control box, the GTOCP3, as its big brothers - the 900GTO and 1200GTO mounts. In fact, the control boxes for all three mounts are interchangeable with one another in an emergency. This cutting edge electronic marvel coupled with software like Ray Gralak's wonderful PulseGuide (included) and your PC make remote operation a pleasure.

Operate with 12V battery or Regulated Power Supply
You can take it to the darkest skies and power it with a commonly available 12V battery. In the observatory, we suggest a minimum 5 amp filtered, regulated power supply.

Clutches and interchangeable motor / gear boxes
Clutches allow manual operation if power is not available. If, heaven forbid, your RA motor fails, simply swap the declination motor / gear box and resume tracking in RA. This will be a much appreciated backup procedure when you are far from home on an extended vacation.

Image Past the Meridian
The mount will track and guide well past the meridian in either direction if the object is located such that the telescope will clear the pier. This allows the user to set up the mount for a long series of exposures without stopping in the middle to flip sides. One can start the telescope under the mount while pointing at an object in the eastern part of the sky and track it all the way deep into the western sky. This is very useful for long exposure H-alpha or in cases where a large number of individual exposures are needed for stacking. Dennis di Cicco had this to say about the "powerful meridian delay feature" in his 2007 review:

". . . makes it easy to set up photographs that track across the meridian without interruption. It may sound like a small feature on paper, but I found it extremely useful in the field . . ."

Easy Alignment for Non-critical Observing
You can align the Mach1GTO using setup routines in the keypad, or with a polar alignment scope to quickly zero in on the pole for most non-critical observing or to get close before tweaking in for imaging. (Polar scope not included. We recommend either the PASILL4 or the prior PASILL3 model since they can rotate in the axis) You can even align the mount during the day with our clever Daytime Polar Alignment Routine (outlined in the Keypad Manual) for solar observing, viewing the planets at twilight, or just getting a jump start on a long night.

External Computer not Needed
The Keypad is a handheld computer with all of the features, functions and databases you need to tour the universe night after night. The unique firmware allows you to precisely polar align your mount in the field, even in broad daylight! The vacuum-fluorescent display with a temperature range of -40 degrees F (and C, they are the same in this instance), allows hardy observers to use this mount on cold winter nights. You can't do that with a PC or PDA! As new firmware versions are released in the future, you can upgrade your keypad directly from the download section of our web site - free of charge!

Control with personal computer, if desired.
All functions of the servo drive can be commanded from a laptop or desktop computer using popular planetarium program or PulseGuide. Depending on the features of the program, you can position your telescope, center your image and control tracking rate, remote focusing, reticle brightness and park at the end of your observing session. Examples of currently available software:

    * PulseGuide by Ray Gralak (included with the Mach1GTO)
    * PEMPro by Ray Gralak
    * Software Bisque's suite which includes TheSky Astronomy Software, CCDSoft CCD Astronomy Software, TPoint Telescope Pointing Analysis Software and Orchestrate Scripting Software.
    * Earth Centered Universe (ECU) by David Lane of Nova Astronomics
    * SkyMap Pro by Chris Marriot
    * Starry Night Pro by Simulation Curriculum Corp.
    * ACP Observatory Control Software by DC-3 Dreams - Robert B Denney
    * Any software that is ASCOM compliant.

Serial to USB connectivity has been simplified by the addition of Keyspan Serial-to-USB devices to our product line.

Write your own computer program.
The Astro-Physics GTO protocol for the GTOCP3 Control Box is freely available to those who would like to write their own computer program for controlling the mount.

Precise Mechanical Fabrication

Highly accurate mechanics
Using modern CNC machining techniques, we make all components to a high precision level, which results in a final package that is solid and accurate in all respects. The critical angles are accurately machined so that the mount is orthogonal to a very high degree. This results in pointing accuracies well below 1 arc minute for a properly aligned mount.

Worm gear accuracy
Critical worm gear accuracy is maintained by special machining techniques developed at Astro-Physics after extensive studies and actual field operation. Our worm accuracies are second to none and are guaranteed to be 7 arc seconds (+/- 3.5 arc sec.) or less peak-to-peak for the Mach1GTO before introducing any periodic error correction! The periodic error of each mount is verified and optimized during our extensive testing procedures as described above. With good alignment and PEM training with the Keypad or PEMPro software, it is quite practical now to achieve unguided CCD images with today's hi-resolution cameras coupled to a 4" to 10" telescope.

Mechanical Features

• All machined mounting made from aluminum bar stock and stainless steel. All fasteners are stainless steel.
• Motors and all electronic components are enclosed.
• Machine tool bearings achieve tremendous rigidity in a small package.
• Polar and declination axes come apart quickly for light-weight, easy handling and ease of transport in a carry-on luggage case.
• Fine altitude and azimuth adjustments for quickly and accurately zeroing in on the pole in the field.
• Electronic components rated for industrial and automotive applications.
• Mach1GTOs will be shipped with a Control Box Adapter Bracket (CBAPT) as well as the familiar Control Box Pouch. The adapter allows the control box to be mounted directly to most of our recommended piers and tripods.
• Pier Adapter (included) fits into our 6” Eagle Adjustable Folding Pier (EAGLE6), Adjustable Wood Tripod (AWTOOO) or 6" outside diameter pier with 0.083" wall thickness (various heights are available).

Specifications of Equatorial Head

Servo Motor Drive

The drive system uses a high-quality Swiss DC servo motor controlled by a microprocessor to an accuracy of 0.05 arc-seconds per step. Tracking is very smooth, noticeably smoother than any stepper motor drive or inexpensive servo motor. The system can be accurately controlled over a speed range of 4800:1, which allows 0.25x sidereal for manual guiding to 1200x sidereal for 5 degree per second slewing. The circuit draws only 0.4 amps when tracking the stars, 2 amps with both motors slewing and requires only 12 volts to operate. The servo drive will satisfy the requirements of the sophisticated, advanced astrophotographer, yet is easy for the casual, visual observer to use.

The GTOCP3 Control Box contains all of the circuitry to drive the two servo motors and the logic required to navigate the sky. It can be easily removed from the mount, if required.

The GTO Keypad is a self-contained computer that serves as the communication center for the operation of your GTO mount. We have designed the interface and firmware to be as intuitive and easy to use as possible while filling it with terrific features to make your observing session productive and pleasurable.

All of the Mach1GTO's electronics are now lead free. Astro-Physics believes that we who love the night sky should also love and protect our good earth.

PulseGuide™ Software

Please note: Ray Gralak, the author of PulseGuide, is currently working on a new piece of software that will combine the Astro-Physics ASCOM driver, all the features of PulseGuide, plus additional features. The new software will also act as a hub for a number of other applications that can then all communicate with the mount through a single COM port. The new software will have a new name befitting its vastly increased capabilities, and will replace PulseGuide when it becomes available. In the mean time, here's the lowdown on the existing PulseGuide software:

PulseGuide is a stand-alone Windows (98, ME, 2000, NT4, XP, Vista and Windows 7) utility that provides complete remote control of the Astro-Physics Mach1GTO, 400GTO, 600EGTO, 900GTO, 1200GTO and 3600GTO mounts. It derives its name from its most distinctive feature, pulse guiding, which can improve unguided tracking. Specifically, it can help correct tracking errors caused by polar misalignment and atmospheric refraction. You can also train PulseGuide to track objects moving relative to the stars, such as asteroids, comets, and the moon. In addition to pulse guiding, PulseGuide also has many useful utility features. With just a few exceptions, it supports the entire serial Astro-Physics command protocol allowing full control of your mount through your PC. This program is indispensable for remote control of your mount.

Pier / Tripod Mounting Options

The Mach1GTO can be mounted directly into the top of an Astro-Physics 6" Portable Pier or on our 6" Eagle Adjustable Folding Pier (EAGLE6). It can also be mounted on the Adjustable Wood Tripod (AWT000) or the Lightweight Adjustable Aluminum Tripod (SDS400).The ADATRI adapter allows the Mach1GTO to be mounted on your own custom pier or tripod and can be purchased separately.

Support

All Astro-Physics mounts are supported by a dedicated staff who will assist with any issues that may arise. You can talk to a real person in a timely manner. Astro-Physics staff also participate the ap-gto user groups in the Yahoogroups forum. The user group is comprised of GTO owners who are willing to share their wealth of experience using their mounts as well as imaging strategies and other concerns of advanced amateurs.