Why a 1600GTO?
Thirty plus years of mount building expertise has been employed to engineer and build our new 1600GTO mount into the most robust, high-precision mount in its class. We have enhanced its design and utility by incorporating additional optional features like absolute encoders, sophisticated control systems and a new precision polar scope to exceed the needs of even the most demanding astro-imager or visual enthusiast. Although we believe that the 1200GTO will continue to provide years of excellent performance, we felt that the time had come to improve the ease of use and add new features to take it into the future. We listened to your suggestions and added a few of our own. Some of them make the mount easier to set up for portable use, others set the standard for remote imaging. The modular design allows you to easily upgrade your mount if you build an observatory for near (backyard) or remote (halfway across the world) imaging.
We also felt that we needed to increase the size differences between the Mach1GTO, 900GTO and the 1200GTO, which were too close together and overlapping. Since the "new 1200" has greater capacity than the original 1200, we felt that it should have another name and selected 1600GTO "Sweet 16". Nevertheless, it maintains the heart of the 1200. Here are some changes that you may find useful:
- Dec. axis gear increased to 10" for higher payloads and more stability
- Azimuth adjusters have been repositioned to the rear of mount which allows you to make minor corrections quite easily without reaching or moving around the mount. Since the knobs are now in front of you as you look through the polar scope, the graduations can be more easily seen as you dial in your position.
- Built-in precision-rotating pier adapter is now included and not purchased as a separate item.
- Major altitude adjustments are extremely easy to make. Simply shift the position of the bar into a new slot without having to line up obscure holes referenced in the manual. The large hand knob is also very easy to grasp and turn. If you travel to a star party at a different latitude, you can make changes to your setup very quickly.
- Altitude range has expanded on both ends and now extends from 0-78 degrees, which makes it suitable for most anyone except the extreme polar locations. The Hi-Low Wedge is no longer necessasry.
- New Right-Angle Polar Alignment Scope can be used without the need for an additional adapter
- Unobstructed Dec. opening for Polar Alignment Scope allows greater field of view for both the Astro-Physics Right-Angle or the Losmandy Style Polar Alignment Scopes.
- Internal routing of motor cables to remove the possibility of snagging.
- Easily route additional cables through the large openings in the R.A. and Dec. axes. The top of the Dec. axis separates so that you can add cables with large connectors.
- Right-angle connectors are used in most locations to reduce strain on the cables.
- Larger motors for increased torque in cold temparatures. These are the same motors as used in the current 3600GTO mount. Note: The 1200GTO mounts produced in 2011 also have these motors.
- Automatic worm gear mesh is quick and easy. Produces the best settings on the worm teeth and repeatable settings.
- Improved clutch system with NO clutch plugs that can potentially deform over time if they are overtightened. This issue has been eliminated.
- Clutch can be set to any amount of engagement up to complete locking of the axes so nothing can slip.
- Control box mounted on the side rather than the top to reduce the possibility of moisture getting into the electronics in damp environments.
- Greater capacity to provide a rigid platform for fairly large instruments or side-by-side setups.
- Absolute Encoder option to provide error-free tracking, software readable absolute position, customizable home and limit functions for robitic imaging. This option can be installed whenever you are ready to take advantage of its capabilities.
The 1600GTO mount is built from the ground up to be a precision imaging platform while still remaining totally user-friendly. Consider these advantages and features:
Extremely solid, rugged, high payload mount, yet the equatorial head comes apart into two components for hassle-free field setup.
Operate with 12V battery.
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 like our 13.8V, 5-amp Power Supply (PS13V5A). For a heavy payload in cold conditions, we offer a 15V, 10-amp power supply (PS15V10AC).
Allow manual operation if power is not available. One of the truly unique features of the 1600GTO is the ability to use the clutches to help you balance your setup, then you can bolt the R.A. and Dec. axes in place so that they do not move for clutchless operation.
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. This feature of our GTO mounts has been a real customer favorite.
Easy alignment for non-critical viewing.
You can align the 1600GTO 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). 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.
Multiple Options for Controlling your Mount in the Field or Your Observatory
You have your choice of the GTO Keypad (included), which is a full-featured handheld computer, PC computers using a wide variety of software with or without our ASCOM driver, Mac computers or even your mobile smart device (like your iPhone or iPad). The Astro-Physics command language is available to those who need to write their own software.
Precise Mechanical Fabrication
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. Massive thrust bearings and preloaded shaft bearings provide excellent stability under all imaging situations.
Easy to Adjust and Maintain
The design of the Mach1GTO is straightforward with modular construction and no complicated internal wiring. We provide information in the Technical Support section of our website pertaining to typical adjustment issues.
Components are modular.
All electronics including the GTOCP3 control box, motors, gearbox or cables can be removed for servicing. The RA and Dec axes can be shipped separately, if needed.
||All CNC machined aluminum bar stock, stainless steel, brass; stainless steel fasteners
|Finishing and Assembly
||Every part is hand-finished and inspected. All assembly is done by hand, by highly skilled mount assembly staff.
|Worm wheel - R.A. & Dec.
||10.3" (262 mm), 225 tooth aluminum
|Worm gear - R.A. & Dec.
||1.22" (31 mm) diameter brass
|Axis shaft - R.A. & Dec.
||3.74" (95 mm) diameter
|Shaft axis bearings - R.A. & Dec.
||5.71" (145 mm) diameter
||0 to 78 degrees
||Approximately 13 degrees (+/- 6.5 degrees from center)
||1.875" (47.6 mm) diameter x 19.5" (495 mm) long [18.5" (470 mm) useable length], incl. large machined safety stop knob. Optional 9" (229 mm) shaft extension available.
|Weight of mount
Total: 115.5 lb. (52.5 kg)
R.A. axis/polar fork: 58.5 lb. (26.6 kg)
Dec. axis: 40.5 lb. (19.5 kg)
Dec. top plate 2.5 lb. (1.1 kg)
Counterweight shaft: 14 lb. (6.4 kg)
||Approximately 200 lb. (90.9 kg) scope and accessories (not including counterweights), depending on length. Recommended for refractors up to our 250 mm, 18-20" Cassegrains, Ritchey-Chretiens and CDKs.
These are only guidelines. Some telescopes are very long for their weight or heavy for their size and will require a larger mount. Remember also that imaging requirements are more rigid than visual observation.
|Instrument mounting interface
||Refer to list of suitable mounting plates below
|Pier adapter base diameter
||9.775" (248.3 mm) Base. The base is an integral part of the mount and azimuth adjuster.
The drive system uses a high-quality, heavy-duty 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 approximately 0.5 amps when tracking the stars, 2.5 amps with both motors slewing and requires only 12 volts to operate. The servo drive will satisfy the requirements of the sophisticated, advanced astroimager, yet is easy for the casual, visual observer to use.
Gear Accuracy and PE Performance
The heart of this mount is a precision gearbox using custom 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 specification of 5 arc seconds (+/- 2.5 arc sec.) before introducing any periodic error correction. The PE is smoothly variant with extremely low ripple or moment to moment error. In contrast, mounts that use integral gearboxes have very small spur gears with tiny teeth and too few of them. This generally causes ripples in the tracking rate which are difficult to guide out.
Each mount is rigorously tested on our specialized periodic error tester. Only mounts that provide an accuracy of 5 arc seconds or better will pass this inspection. If the mount exhibits greater error, the substandard part is identified, replaced and the mount is retested.
Pre-loaded PEMPro Curve
As mentioned above, the spec of 5 arc seconds (+/- 2.5 arc sec.) is the maximum native mechanical error inherent in the mount's RA axis WITHOUT any software correction. In order optimize performance even further, we use a special version of Ray Gralak's PEMPro (described below) developed specifically for our test equipment. We generate a unique PE curve for each mount that we program into each GTOCP3 Control Box. Simply use the Keypad or your Astro-Physics software (ASCOM V2 driver, PulseGuide or APCC) to turn the PE Correction "on" and you will see results significantly better than our published 5 arc second spec without additional PEMPro runs! However, you may use PEMPro to further refine your PE, if you chose to do so.
GTOCP3 Control Box
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 1600GTO uses the same GTOCP3 Control Box as the 900GTO and Mach1GTO (the control box is black-anodized for the latter mount). In fact, the control boxes for all three mounts are interchangeable with one another in an emergency.
The Keypad is a self-contained computer that allows you to control all essential telescope functions and includes an extensive database of objects. 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.
GTO Servo Drive System Specifications
||Rated for industrial and automotive applications
||High-torque, zero-cogging Swiss DC servo motors, enclosed in machined aluminum housing
||2000 tic quadrature yielding an effective resolution of 0.050 arcseconds per tic
|Motor reduction gear train
||57.6:1 gear reduction through a custom built set of large diameter, fine-toothed, precision, spur gears for vastly superior performance
|Servo Motor Control Box
||GTOCP3 Control Box, removeable
||GTO Keypad to control all mount functions. Includes extensive databases and tour features in a simple, intuitive interface. Firmware updates via the internet
||~ 0.3 to 0.6 amps at 13.8 volts - tracking
~ 1.3 to 2.5 amps at 13.8 volts - both motors slewing at 1200x
||Nominal 12 volt DC supply at minimum of 5 amps continuous
5 arc seconds peak-to-peak (+/- 2.5 arc seconds) or less in one worm cycle (6.4 minutes); native, prior to any error correction
|Maximum slew speed
||5 degrees / second
Absolute Encoders (optional)
The 1600GTO mount has been designed and engineered to accomodate the use of extremely precise Absolute Encoders. Absolute Encoders allow the mount to know its exact location regardless of accidental software errors and will allow it's recovery. This is particularly important in remote setups. Furthermore, they virtually eliminate periodic error, reducing it below 0.2 arcseconds in our tests. The encoders can be user installed on both axes, or on just the RA axis based upon the user's need. This frees the user from having to make the decision to include the encoders at the time of the mount's purchase; rather, they can be added later as need arises. Check out the 10 minute (600 seconds) unguided exposure by clicking on the thumbnail below.
Absolute Encoder Options CLICK HERE
Flexible Control with Your Keypad, Computer or even your Mobile Smart Device!
As this chart shows, there are many options available for controlling your mount whether you are out for a night of observing your favorite objects without a PC (your Keypad serving as your handheld computer), conducting a public star party (imagine using an iPad to "WOW" the kids) or remote imaging (APCC will allow you to control your mount in the comfort of your home).
Your Astro-Physics GTO mount has a remarkable servo control system that combines with the precise mechanics of the physical components to give the mount its superb performance. Contrary to popular assumption, the brains of the mount are found in the GTO Control box, not in the kkeypad or computer program. Simply think of your Keypad or computer as an input device.
All functions of the servo drive can be commanded from a laptop or desktop computer. Astro-Physics now has a wholly-owned and fully-supported ASCOM V2 driver for all of our GTO mounts. This is the recommended method for mount control with a personal computer operating under the Windows operating system. Most popular Windows planetarium, imaging, guiding and observatory control software take advantage of ASCOM’s universal applicability. Refer to additional information regarding the V2 driver below.
The GTOCP3 control box provides two RS-232 inputs so that you can connect with two separate serial interfaces. This allows Mac users and non-ASCOM programs to have more than a single connection to the mount. For example, you might wish to connect PulseGuide and an ASCOM client at the same time with your Windows computer. On the Mac side, you might wish to connect both Astro-Planner and Equinox for an observing or imaging session. Please note that we cannot fully support Mac programs at this time.
Serial-to-USB connectivity has been simplified by the addition of Keyspan Serial-to-USB devices to our product line, and the Icron Ranger USB Extender.
GTO Keypad Operation
The GTO Keypad (included with all GTO mounts) is a handheld computer with all of the features, functions and databases you need to tour the universe night after night. The vacuum-fluorescent display with a temperature range down to -40 degrees F (and C, they are the same in this instance), allows hardy observers to use the keypad on cold winter nights (please contact Astro-Physics if you wish to use the mount in severe temperatures below -20F).
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, 900GTO, 1200GTO, 3600GTO, 400GTO and 600EGTO 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.
Astro-Physics ASCOM V2 Driver
Astro-Physics now offers a company-supported ASCOM V2 driver. This driver provides full mount control for all of the Astro-Physics GTO mounts and acts as a hub allowing multiple client applications to connect through a single serial port without the need for POTH. It has been developed with remote operation in mind and its functions were designed to be highly robust. The driver features a very user-friendly graphical user interface (GUI).
The ASCOM V2 Driver is compatible with all versions of the GTO Control Box: GTOCP1, GTOCP2, GTOCP3.
Astro-Physics Command Center (APCC) Software
Ray Gralak, the author of PulseGuide, developed the Astro-Physics Command Center (APCC), which incorporates all the features of PulseGuide and add many more advanced functions to the control system of your mount. Through the application of virtual serial ports, APCC acts as a hub for a number of other applications that can all communicate with the mount through a single COM port.
- Virtual serial ports to connect multiple applications
- Customizable meridian limits that work in conjunction with an improved meridian delay feature
- Customizable horizon limits
- Highly sophisticated pointing model and variable tracking rate for both axes
- 3-D modeling of your telescope's position showing the orientation of the scope and mount for remote users
- Complete mount control including terminal interface
APCC can only be used with the GTOCP3 control box since it takes advantage of advanced features available only in the CP3.
Planetarium, Imaging and Observatory Software from Other Vendors
There are a number of planetarium programs that can be used to control the Astro-Physics GTO Servo System. In addition, some software designed primarily for camera control and/or observatory control and planning also have limited ability to control your mount. Many of these use the ASCOM interface and will take advantage of the new ASCOM V2 driver mentioned above. Any software that can use the AP V2 ASCOM driver will have extensive mount control capabilities because of the driver's "virtual keypad" features. Other programs employ native drivers that the software designers wrote from our publicly available command set. The list that follows is certainly not exhausive, but contains software with which we have at least a little familiarity.
- TheSky and Bisque Observatory Software Suite™ families of products from Software Bisque. These include TheSky 6™ Professional Edition (Windows), The Sky X™ (Windows and Mac versions), TPoint™ (Windows and Mac versions), CCDSoft™ - jointly developed with SBIG (Windows), Orchestrate™ and other components in the Bisque Observatory Software Suite. The Bisque brothers have written their own native Astro-Physics drivers and their Windows programs can also use the ASCOM interface. We recommend that you use the ASCOM interface for more complete and fail-safe control.
- Starry Night Pro Plus™ by Simulation Curriculum Corp.(Windows version with ASCOM support and Mac version with native driver)
- Earth Centered Universe™ (ECU) v3.1 or later from Nova Astronomics (Windows). As of Feb. 2010, the latest version was v.5.0. Versions including 4.0 and later have full client support for ASCOM telescope drivers including the Astro-Physics V2 ASCOM driver.
- SkyMap Pro™ (Windows) by Chris Marriot. Native drivers for the Astro-Physics GTO system have been included since v.7. Starting with V.10, ASCOM support was added as well.
- Equinox™ from Microprojects Astronomy Software - Darryl Robertson (Mac)
- Voyager™ from Carina Software (Windows and Mac). This product does not use the ASCOM interface.
- SkySafari™ for Mac OS X by Southern Stars - This software is offered through the Mac App Store in three versions. They do not use the ASCOM interface.
- ACP™ Observatory Control Software by DC-3 Dreams - Robert B. Denny (Windows). ACP™ uses the ASCOM interface. Since all observing and automation accomplished through the web browser, you can use your mobile smart device to access the controls for your mount.
- MaximDL™ from Diffraction Limited (Windows). Imaging software that uses the ASCOM interface.
- CCDWare Product Suite from CCDWare (Windows). The suite includes CCDNavigator™, PEMPro™, CCDInspector™, CCDAutoPilot™ Professional and CCDStackImaging software. They all use the ASCOM interface. These products can also be purchased individually.
- Any software that is ASCOM compliant. Be sure that you update to the most current ASCOM V2 driver, which is supported by Astro-Physics.
Mobile Smart Devices
We have entered a new age of smart devices that offer amazing functionality at our fingertips without the need for a computer.
SkyFi™ Wireless Telescope Controller and SkyWire™ from Southern Stars
SkyFi™ is Southern Stars' patent-pending WiFi-to-Serial adapter that is designed for wireless telescope control. If you have a computer-controlled GoTo telescope, SkyFi™ can use the WiFi capabilities of your Mac, PC, iPhone™, iPad™, or iPod Touch™ to point your telescope (via your mount) in the sky.
SkyWire™ can connect the iPhone™, iPad™, or iPod Touch™ directly to your mount via wired connection. It has an Apple device plug on one end and an RS232 plug on the other.
In 2010, Southern Stars' SkyFi™ and SkySafari™ (discussed below) were Macworld Expo 2010 Best of Show winners (both products were marketed by Carina Software at the time of the award).
SkySafari™ for iOS from Southern Stars
As of this writing, SkySafari 3™ is available in three different versions, two of them offering telescope control. All of these versions are available as iTunes™ Apps and require use of the SkyFi™ Wireless Telescope Controller or SkyWire™, as described above.
The GoTo mount control functions provided by this application are quite basic and most suited to visual astronomy. However, the graphical interface of your iPad™, iPod Touch™ or iPhone™ offers some exciting possibilities to engage kids (young and old) at public star parties, as well as provide an enjoyable, informative evening for amateur astronomers on observing nights. Also, if the weather is cloudy, you can browse through the extensive databases to learn a great deal about the sky and plan your next session. This product is also being offered in a version for the Mac OS X for direct computer control.
PEMPro Software, Version 2
PEMPro (Periodic Error Management Professional), Version 2, by Sirius Imaging is a very powerful Windows software application that allows the you to correct your mounts periodic error, polar alignment and backlash using your CCD Camera or Webcam to dramatically improve tracking and guiding. As mentioned previously, our extensive testing procedures include several PEMPro runs so that your new mount will perform with optimum PE correction out of the box. Simply use the Keypad or the PulseGuide software to turn PE Correction "on." Although you will not need to use PEMPro when you receive your mount, you may wish to do a PEMPro run at a later date after the worm gear has run 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.
Pier Mounting Options
The 1600GTO mount integrates a precision rotating pier adapter and azimuth adjuster as part of its base. The mount's base will directly attach to the Astro-Physics pier, or it can be attached to any flat surface using the Flat Surface Adapter for 1600GTO and all 1200 Mounts (1612FSA). When choosing the Advanced Telescope System's (ATS) Pier, you will need to order our Flat Surface Adapter with Flat Pier Plate 1612FSA-FP that will fit into the top of their pier. The 1600GTO's large adjustable 0 to 78 degree latitude range (which spans from Antarctica to the arctic circle) makes the use of a wedge unnecesary.
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.
1600GTO - What's Included?
- Polar Fork/ Right Ascension Axis (R.A.) Assembly
- Declination Axis (Dec.) Assembly
- GTO Servo Control Box (GTOCP3)
- GTO Keypad with 15' Coiled Cable and Keypad Protector (KEYVFK)
- 19.5" Stainless Counterweight Shaft, 1.875" diameter (M12601-D) and Safety Stop (M12676)
- R.A. and Dec. Cables
- 8' Power Cable (CABLPF)
- 15' Straight-through Serial Cable (CABSER15)
- Allenhead wrench set
- Astro-Physics Keystrap and Velcro Cable Ties
- CD containing: PEMPro v2 Software and PulseGuide Software, both written by Ray Gralak of Sirius Imaging. Also, PDF of 1600GTO and GTO Keypad instruction manuals
- Manual: 1600GTO German Equatorial
- Manual: GTO Keypad
- Registration Card
Items that You will Need for Your Mount
- Counterweight: Stainless Steel Counterweights - 5, 10, 18, 24 lb.
- Saddle Plate: DOVELM162, DOVELM2, DOVEPW, 1200RP, 1200RP15, FP1800, DOVE15
- D-Style (3") Dovetail Plate: D-Style Dovetail Plates, 13" and 16" Side-by-Side Plates (SBD13SS and SBD16SS) and Vixen Dovetail Converter (SBD2V)
- P-Style (7.65") Dovetail Plate: 23" PlaneWave Style Dovetail Plate (SBPW23)
- Pier: Astro-Physics Portable Pier - 10" diameter, heights 24",32",42",48",54",62", Advanced Telescope Systems (ATS) Portable Pier or build your own permanent pier
- Regulated Power Supply: 13.8V 5-Amp (PS138V5A) or 15V 10-amp (PS15V10AC) Regulated Power Supply with Cigarette Adapter
- Portable Rechargeable 12-volt Battery Pack: Several sizes and types are available from a variety of vendors. Be sure that your battery pack can supply adequate power for an entire observing session! We recommend having separate batteries - one for the mount and another for all other accessories: camera, dew removers, etc. We do not offer any battery packs at this time.
Additional Accessories to Consider
- Absolute Encoders
- Right-Angle Polar Alignment Scope with LED Illuminator - 1600GTO, Mach1GTO and all 900 and 1200 Mounts (RAPAS) - available Fall 2012
- Losmandy Polar Alignment Scope with LED Cable for 1600GTO (PASILL4L-179)
- Kit to Adapt a Losmandy Polar Scope to 1600GTO Mounts (PASILLKIT-179)
- Losmandy Polar Alignment Scope Adapter for 1600GTO (Q16030)
- 9" Counterweight Shaft Extension (M12675)
- Flat Surface Adapter (1612FSA)
- Flat Surface Adapter with Flat Pier Plate for 1600GTO and all 1200 Mounts - For 10" ATS and other non-Astro-Physics piers (1612FSA-FP)
- Pier Accessory Trays and Support Bar
- Serial to USB Computer Connectivity Products