ASTRO-PHYSICS
3600GTO German Equatorial Mount (3600GTO)
and
3600GTO German Equatorial Mount with Precision Encoder (3600GTOPE)
" el Capitan "
Featuring GTO Servo Drive System
Includes GTOCP3 Control Box, GTO Keypad and CD with PulseGuide and PEMPro v.2 software (full version)

Solid as a rock!

El Capitan is the ultimate imaging platform for large instruments:
RC Optical Systems - 20" or 24" Ritchey-Cretiens
PlaneWave Instruments - CDK17, CDK20, or CDK24
Optical Guidance Systems - RC20 or RC24 or instruments of similar size.
Setups that employ smaller multiple instruments would also be ideal.

Why a 3600GTO ?

The 3600GTO is the culmination of over 30 years of experience designing and building mounts at Astro-Physics for the amateur and professional astrophotographer. We take great pride in the soundness of our designs, the quality of our workmanship and unparalleled support of our customers.

"I am in the process of planning a trip to the remote observatory I own at Arizona Sky Village. I realized that the last time I was there was to install the AP3600GTO in April of last year, and that since that time it has been operating every clear night and has not missed a beat ...The mount has been running for over one year and surpassed my expectations in every way". David Churchill. Read more of his comments here.

At the Advanced Imaging Conference (AIC) in late October 2010, Roland Christen demonstrated how "El Capitan" can easily hold (and track) with a 24" PlaneWave Corrected Dall-Kirkham (CDK) in an inverted position (scope underneath the counterweights). The scope weighs 240 lbs. and the counterweights are an additional 240 lbs. The mount never broke a sweat. Ray Gralak took some videos showing the 24" CDK slewing, which we encourage you to enjoy at this link: 3600GTO slewing 24" CDK. If you listen carefully to the sound of the mount slewing in these videos, you will not hear any difference in the sound whether the telescope is in a more normal position or underneath the mount. It carries the telescope in all positions with ease. You can also view additional videos and photos of the conference.


We offer two versions of this mount: the 3600GTO is the standard version and the 3600GTOPE includes the built-in Precision Encoder System. Both are available with the optional Limit/Homing Switch System. If you have a large instrument or several smaller instruments, we invite you to review the information below.

Mechanical Features

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.

. . . I love the ability to place the OTA on the "wrong side" of the mount when starting an imaging session ("premature meridian flip") and which I have used extensively. This feature is pure INGENUITY! Anthony Ayiomamitis., More… (commenting on his 1200GTO that uses the same control system. All AP mounts have this feature!)

Full 360 degree rotation of both axes.
The full 360 degree rotation of both of the 3600GTO's axes also allows this mounting to be placed onto an astrographic pier for complete freedom from movement restrictions. Contact ATS (Advanced Telescope Systems) to discuss astrographic piers.


Through-the-mount cabling capability.
We designed this mount to allow cabling to be run through the axis shafts for tangle and clutter-free operation. Cables from cameras, guiders, dew heaters and the mount's own servo drive cables can all be run through the mount's cavernous 4" hollow shafts where they are out of the way and where they won't ever get caught or tangled during your imaging session. Ports have been included for the mount's servo cables. Additional ports can be added by the user, as needed.

Components are modular and easy to maintain.
The design of the 3600GTO is straightforward with modular construction and no complicated internal wiring. 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. The mechanical design of the mount is extremely simple and straightforward, allowing easy adjustment by anyone - no need to have a mechanical engineering degree to service the mount. We will provide information in the Technical Support section of our website pertaining to typical adjustment issues.

Integrated Pier Adapter
The pier adapter for the 3600GTO has been integrated into the mount's design and incorporates the design principles of the Precision Adjust Rotating Pier Adapters available for our smaller mounts. In an innovative twist, the Super Heavy-Duty Azimuth Adjuster is UNDER the BACK of the mount where it is both conveniently located for fine polar alignment and remains out of the way. Polar alignment is smooth and easy, and the system locks down tight with no unintended movement.

For most installations, we recommend using our 3600 Flat Surface Adapter (3600FSA). Many of the photos on this page are of a prototype mount and prototype ATS Portable Pier. The photos do not include this recommended adapter.

Easy to Adjust and Polar Align.

Precise polar alignment can be achieved easily using the precision adjusters for both altitude and azimuth. The system locks down with zero alignment shift for an unprecedented ability to achieve that "perfect dead-on" polar alignment that is so critical to the best imaging and the most accurate go-to slews.

The PEMPRo Software program (included with the mount) includes the "Polar Alignment Wizard," a powerful feature that allows you to dial in on the pole quickly.

Transportable
Extremely solid, rugged, high-payload mount, yet the equatorial head comes apart in two components for transport and field setup. Because of this mount's size and weight, we recommend that field assembly be done by at least two people working together. The RA axis/base assembly alone weighs just over 120 lbs. You wouldn't want to transport it as your regular mode of operation, but it can certainly be done for special occasions.

The 3600GTO is shown in the photo on the right with a 12" x 30" portable pier developed by ATS (Advanced Telescope Systems). You can review more information regarding ATS pier options by clicking here. As noted above, the photo at right does not include the recommended 3600 Flat Surface Adapter (3600FSA). ATS 12" piers can now be purchased with a flat top plate which has been drilled and tapped to accept this adapter.

ATS also makes permanent piers for the 3600GTO that can be fitted with the same flat top plate. Please see the ATS website for details on their permanent piers.

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.

Our machinists are among the most skilled available anywhere, attending to the smallest detail to ensure a precision instrument. The finishing department assures that all parts are deburred, sanded, polished and painted to provide an exceptional aesthetic appearance. Our mount assembly is directed by a life-long astronomer with more than 20 years of experience here at Astro-Physics! All of our production personnel take great pride in their work and are true craftsmen and women.

Worm gear accuracy.
Critical worm gear accuracy is maintained by special machining techniques developed at Astro-Physics after extensive studies, actual field operation and many years of experience making precision mounts. Our worm accuracies are second to none and are guaranteed to be 5 arc seconds (+-2.5 arc sec.) or less, peak-to-peak. The periodic error of each mount is verified during our intensive testing procedures prior to optimization as described below.

Pre-programmed with PEMPro
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 5 arc seconds (+/- 2.5 arc sec.) is the maximum native mechanical error inherent in the mount's RA axis WITHOUT any software correction. We optimize performance further by characterizing the error using a special version of PEMProAP and downloading the appropriate correction into the mount's GTOCP3 before it leaves Astro-Physics. Simply use the Keypad or PulseGuide software to turn PE Correction "on," and you will see results that are even better than our published 5 arc second spec! With additional PEMPro runs, you can achieve even higher levels of accuracy.

If your application requires the highest possible levels of tracking accuracy, you may want to consider the Precision Encoder System described below.

Mechanical Specifications

Construction 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. 13.0" (330 mm), 256 tooth aluminum
Worm gear - R.A./Dec. Brass, 1.41" (35.8 mm) diameter
Axis shaft - R.A./Dec. 4.72" (120 mm) diameter with 4.02" (102 mm) clear inside diameter
Shaft axis bearings - R.A./Dec. 7.09" (180 mm) diameter deep groove ball bearings
Worm gear bearings 1.57" (40 mm) angular contact ball bearings
Latitude range 15-70 degrees
Azimuth adjustment Approximately 14 degrees (+/- 7 degrees from center)
Counterweight shaft 2.5" (64 mm) diameter x 31.5" (800 mm) long [30" (760 mm) useable length], incl. large machined safety stop knob. Will fit 12 optional 30 lb. (13.6 kg) counterweights. Optional 10" (254 mm) shaft extension available.
Weight of mount Total: 247 lb. (112.3 kg); R.A. axis/polar fork: 121 lb. (55 kg), Dec. axis: 84 lb. (38.2 kg),
Counterweight shaft: 42 lb. (19.1 kg)
Capacity Conservatively rated for 300 lb. (136.4 kg) scope and accessories (not including counterweights). Recommended for: 20" and 24" Ritchey-Chretiens and CDKs.
Please feel free to call and discuss your application with our staff.
Instrument mounting interface

Declination hub has ten 3/8-16 tapped holes on a 12.000" bolt circle. Pdf available

Diameter of base 11.480" (291.6 mm) diameter. Use of the Flat Surface Adapter (3600FSA) is highly recommended.

GTO Servo Drive System Specifications

Electronic components Rated for industrial and automotive applications
Motors High-torque, zero-cogging Swiss DC servo motors, enclosed in machined aluminum housing
Motor encoder 2000 tic quadrature yielding an effective resolution of 0.044 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
Hand-held computer GTO Keypad to control all mount functions. Includes extensive databases and tour features in a simple, intuitive interface. Firmware updates via the internet
Power consumption ~ 0.4 to 0.8 amps at 15 volts - tracking
~ 1.5 to 3.0 amps at 15 volts - both motors slewing at top speed of 600x
Power requirements Nominal 15 volt DC supply at 10 amps recommended
Periodic error

5 arc seconds peak-to-peak (+/- 2.5 arc seconds) or less in one worm cycle (5.6 minutes); native, prior to any error correction

Maximum slew speed 2.5 degrees / second

Servo Motor Drive

The drive system uses a high-torque precision Swiss DC servo motor in each axis controlled by a microprocessor in the GTOCP3 control box.   The encoders on these motors provide a resolution of 0.05 arc seconds per step for incredible pointing accuracy.  Tracking is very smooth, noticeably smoother than any stepper motor drive or inexpensive servo drive. The system can be accurately controlled over a speed range of 4800:1 which allows 0.25x sidereal for manual guiding to roughly 720x sidereal for 3 degrees per second maximum slew rate. The circuit draws well under an amp when tracking the stars, 3 to 5 amps with both axes slewing and requires only 12 volts to operate (15-18 volts is recommended). This 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 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. Please refer to GTOCP3 Control Box and Keypad for Servo Drive for more detailed information.

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

For reliable operation in your observatory, we recommend that you use a minimum 10 amp filtered, regulated power supply like our 15V, 12-amp power supply (PS15V12AC). For lighter, well-balanced loads, you can use a commonly available heavy-duty, deep-cycle marine 12V battery.

Flexible Control with either Keypad or Personal Computer

Keypad Operation
The keypad 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. Additional information regarding the features of the keypad are at this link: GTOCP3 Control Box and Keypad for Servo Drive.

As new firmware versions are released in the future, you can upgrade your keypad directly from the download section of our website - free of charge!

Remote Control with personal computer, if desired.
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 now 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. The Astro-Physics V2 ASCOM driver also acts as a hub allowing multiple client applications to connect through a single serial port without the need for POTH.

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 as well as 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. Please review the information regarding connectivity products to determine which one will work best for your set-up. Here are some of the more popular programs:
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.

Resources for Mac users.
The Mac in Astronomy by David E. Illig. Website: http://www.primordial-light.com/macastronomer.html


Precision Encoder System for the 3600GTOPE Version

Please note that the Precision Encoder System is only included when you order the 3600GTOPE version of the mount. It is not included in the standard version (3600GTO) and cannot be retrofit at a later date.

A precision encoder installed in the RA axis provides feedback to the servo to eliminate periodic error to a level below 1/2 arc second for long-period exposures.   This feedback system eliminates periodic error by monitoring the actual output speed of the RA axis using this encoder ring to continuously adjust the speed of the servo motor, which keeps the axis rotating at a very precise and constant rate. The operation of the encoder does not interfere with any external guiding, centering or slewing commands sent by the keypad, CCD camera or external software. Its only function is to keep the axis tracking precisely at the sidereal rate, and will also follow any variable rate that is programmed into the servo for purposes of countering atmospheric refraction and other sources of drift.

Test results on the new 3600 mount with optional feedback encoder have exceeded all our expectations. The measured tracking error was well below 1/2 arc second for a 20 minute time period. With this option, it is now practical to do long period unguided imaging with a fixed setup where other sources of drift (due to polar misalignment, tube flexure, etc) have been minimized or eliminated.

Astro-Physics pioneered the use of precision encoders, normally used in the machine tool industry, to help you achieve optimal results during unguided or guided astrophotography. The 9" stainless steel Renishaw encoder that we have chosen is dimensionally stable and has guaranteed subarc second resolution over a 24 hour cycle. It is precisely aligned with the corresponding Renishaw Read-Head and tested. This is not a simple tape encoder, which cannot guarantee precise alignment and can shrink with temperature.

The system has been under test since late 2007 and we invite you to review our document entitled: Precision Encoder for the 3600GTO. We have anticipated the questions you may have, i.e. What does the encoder do? How does the encoder do this? and have provided these answers for your review.

To further refine the unguided error of the mount, we are adding an all-sky tracking rate to the software, which will minimize RA drift everywhere in the sky. This will allow significant unguided exposure times with a well polar-aligned mount.

PulseGuide™ Software

Please note: Ray Gralak, the author of PulseGuide, is currently working on a new software program, Astro-Physics Command Center, that will include all the features of PulseGuide, plus additional features. The new software will replace PulseGuide when it becomes available. In the meantime, here's the information 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 Astro-Physics Mach1GTO, 400GTO, 600EGTO, 900GTO, 1200GTO, 1600GTO 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. More ....

PEMPro v. 2.0 Software - FULL Version!

PEMPro (Periodic Error Management Professional) is a Windows software application developed by Ray Gralak that makes it easy to characterize and reduce periodic error. While the periodic error of your 3600GTO has already been optimized with a special version of PEMProAP to be well under 5 arc seconds (+-2.5 arc sec.) or less, you can reduce it even further to maximize performance without auto-guiding. PEMPro v. 2.0 is the latest version of PEMPro and includes exciting new features like the "Polar Alignment Wizard" to quickly, accurately and easily dial in your polar alignment. The software will be included with all new 3600GTO mounts. More ...

Optional Accessories To Enhance the Performance of Your Mount

Limit/Homing Switch System for the 3600GTO (36LSS)
Optional switches can be installed to control operation past the meridian and for homing. The Limit/Homing Switch System can be used as a simple electronic switch or can be used in conjunction with software to establish limits. All mounts will be drilled and tapped to accept this option, which can be added as an upgrade later and installed by the customer. Please refer to the document entitled: Limit/Homing Switch for the 3600GTO for a discussion of these options.

If you have also purchased the 3600GTOPE that has the precision encoder. You will also need to purchase 3600GTO Cable to Connect Limit Switch Connector on Cable Port Plate to GTOELS (CAB36LS) below.

36LSS$530.00 in stockAdd 36LSS To My Cart


3600GTO Cable to Connect Limit Switch Connector on Cable Port Plate to GTOELS (CAB36LS)
This cable is needed if you plan to control your Limit Switches with the GTOELS Control Box.
CAB36LS$94.00 in stockAdd CAB36LS To My Cart


30 lb. (13.6 kg) Counterweight for the 3600GTO (30SCWT)

This stainless steel counterweight was designed to fit onto the 2.5" diameter shaft of the 3600GTO. It features a spring-loaded, recessed lock knob and measures 7.9" in diameter by 2.5" thick.

30SCWT$365.00 in stockAdd 30SCWT To My Cart


22" Dovetail Saddle Plate (DOVE3622), 22" Dovetail Sliding Bar (SB3622, no longer available) and 27" Dovetail Sliding Bar (SB3627) for the 3600GTO

The massive and sturdy two-part telescope mounting system provides the convenience of a dovetail with the security of a fixed mounting plate. It was designed for strength, rigidity and versatility. The dovetail system can be set up for tip-in or slide-in of the dovetail sliding bar. Safety slots on the saddle plate coupled with the sliding bar's safety stop will help keep accidents from happening.

For permanent installations, a series of matching through-holes in the saddle and tapped holes in the sliding dovetail plate allow the setup to be bolted into its final position through both plates once adequate balance is achieved. As an added feature, the saddle plate has two cable-routing channels on the eyepiece end, each 2" wide and approximately 0.5" high. These channels allow you to access the large opening at the top of the dec axis to run your cables through the mount. Refer to the cabling section of the manual (for the mounts shipped in 2008/2009) to see how easy this is.

The dovetail plate is drilled on the underside of the eyepiece end so that you can attach a plate that can be customized as a cabling port. The photo on the right shows a blank plate attached.

22" Dovetail Saddle Plate (DOVE3622) The DOVE3622 saddle plate (shown in the photo to the right) is a female dovetail and features four spring-loaded clamps that will grip the largest instrument solidly. It can be attached to the mount in three possible positions – centered, forward or back depending on the balance point of your instruments.

HISTORICAL REFERENCE ONLY: 22" Dovetail Plate (SB3622, no longer available) This robust male plate, pictured at left, features a myriad of holes throughout the entire length that can accommodate a variety of instrument configurations at various balance points. This plate can accommodate instruments that have hole spacings of 3.2” (Astro-Physics hole pattern), 3.5”, 5.5” and 7.45”. As you can see in the photo, these holes extend from one end of the plate to the other allowing you to space rings as you wish. You can also use two (or even three, depending on instrument size) 16" Dovetail Plates (DOVELM162, new style introduced February 17, 2009) in a side-by-side configuration for multiple instruments. The DOVELM162 is drilled to attach directly onto the SB3622. The DOVELM162 also features lock-down knobs that can be firmly tightened with an allen wrench.

27" Dovetail Plate (SB3627) This plate is similar to the SB3622, however the additional 5" of length make it a great choice for extra-long instruments or side-by-side configurations. Our own experience mounting our prototype 305mm f3.8 Riccardi-Honders and 305mm f12.5" Maksutov-Cassegrain pointed out the need for a longer plate. Hole spacings include: 3.2"-3.5" slot, 3.937", 4.5", 4.921" 5.5", 6.875", 7.450"and 8.220" to accommodate an even wider variety of instruments. They are repeated throughout the length of the plate. Suitable instruments include: All rings with the Astro-Physics hole pattern, 305mm f3.8 Riccardi-Honders, and large Takahashi instruments. The DOVELM162 can be bolted on for side-by-side configurations as mentioned above.

Other options: If these plates do not meet your requirements for the instrument you have chosen, we will work with the manufacturer of the telescope (or other instrument package) to develop a solution. As of this writing, we are working with PlaneWave Instruments to design a special mounting plate for their large CDK scopes.

22" Dovetail Saddle Plate for the 3600GTO (DOVE3622)
12.9" x 22" (328 x 559 mm), 15 lb. (7 kg)
DOVE3622$720.00 in stockAdd DOVE3622 To My Cart

27" Dovetail Sliding Bar (SB3627)
9.9" x 27" (251 x 686 mm), 13 lb. (6 kg)
Please review the Hole Pattern Chart.

SB3627$475.00 in stockAdd SB3627 To My Cart



16.5" Dovetail Plate for PlaneWave (DOVEPW)

In order to accommodate the wide PlaneWave Instruments dovetail plate offered with their CDK17, CDK20 and CDK24 telescopes, Astro-Physics has designed a new 16.5" Dovetail Saddle Plate. This plate features four clamps and can be used with the Astro-Physics 3600GTO, 1600GTO and 1200GTO Mounts. Click here for additional information.



Flat Surface Adapter for the 3600GTO (3600FSA)

We strongly recommend the use of a flat top-plate and our 3600 Flat Surface Adapter when designing your setup for the 3600GTO mount, whether on a portable or a permanent pier. Bolt this adapter onto the flat plate at the top of your pier.

The 3600GTO fits into the ID of the adapter; eight side bolts hold the mount in place. This adapter is machined from a solid plate and is ribbed in the base for strength and reduced weight. It is 12" OD, 1 7/8" tall and weighs 5.75 lb.

Bolt circle:

  • Eight (8) holes for 3/8" bolts on a 10.788" diameter bolt circle
  • Three (3) holes for 5/16" bolts spaced 4.25" from the center and one (1) hole, also for a 5/16" bolt 3.125" from the center. This spacing allows you to attach the adapter to the 1200 Standard Pier Adapter (1200SPA), which allows it to be used with a 10" diameter pier. We used this option before our pier was completed. Please note that this is not a recommended practice for a permanent setup or for a very large instrument.
  • Center hole for a 5/16" bolt to use if you chose.
  • Click here for a dimensioned drawing (PDF)

3600FSA$325.00 in stockAdd 3600FSA To My Cart


11.5" Counterweight Shaft Extension for the 3600GTO (M3655)

This 2.5" diameter extension is beautifully machined from the same 303 stainless stock as the full counterweight shaft of the 3600GTO and adds another 10" of usable length. The fit of the extension on the primary counterweight shaft is virtually seamless, so your weights will slide up and down smoothly. The large machined counterweight safety stop knob threads into the end to protect your toes. The shaft weighs 13.5 lb. (6.1 kg)

M3655$160.00 in stockAdd M3655 To My Cart


3600GTO Shipping Crates, set of two
These crates are required for shipping the 3600GTO. One crate will contain the declination axis and the other will contain the RA axis and polar fork assembly.
36CRATES$550.00 in stockAdd 36CRATES To My Cart


Current Installations

The 3600GTO and 3600GTOPE mounts have been installed in a wide variety of institutions including universities, research organizations, astronomy clubs, community organizations and foundations committed to the education of children, company engaged in solar power research, and private individuals. They are located in Antarctica, Australia, Chile, China, Germany, France, Mauna Loa in Hawaii and other locations throughout the U.S. Check out these photos of mounts with various instruments.

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 in 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.

We have prepared some pertinent support documents, including the 2008/2009 manual relating to this mount and many of our other products on our Technical Support page. You may find the information that you need simply by clicking here.

Price and Delivery Information

The 3600GTO and 3600GTOPE are currently out of stock and we are unable to accept additional orders until the next production run which is estimated for 2014.

If you would like to be notified when the 3600GTO is available to order, please sign up on our online notification form . An automatic confirmation e-mail will be sent to you for your records. Refer to Notification Update periodically to find out the status our mount and telescope production runs - what we are making throughout the year. Please refer to our availability page for more information regarding our notification lists.

Please note that the prices below represents the most recent price in late 2012. The prices for the new production may be different.

3600GTO - $19,900
3600GTOPE - $26,700

3600GTO - What's Included?

3600GTOPE (with the Precision Encoder) - What's Included?

Items that You Will Need for Your Mount

Refer to the information above for these items or links provided:

Optional Items

Refer to the information above for these items:

Additional Recommended Accessories

Copyright © 1999-2011, Astro-Physics, Inc. - All Rights Reserved
This page was last modified: September 11, 2013

Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL  61115, U.S.A.
Phone: 815-282-1513   Fax: 815-282-9847