10Micron GM 4000 HPS II Absolute-Encoder GOTO Mount

The 10Micron GM4000 HPS II German equatorial mount is the last and largest mount in their equatorial mount line-up. It shares the same high level of Italian engineering, craftmanship, build quality and features of all the other 10 Micron HPS mount range.

With a weight of 125kg (276lbs; mount head only) this mount is designed for use in a permanent observatory. The GM4000 mount can carry a total equipment payload of up to 150kg (330lbs). This makes it an ideal mounting for instruments such as, for example, 300mm aperture refractors, 400mm diameter Newtonians and 600mm Cassegrain-type reflectors (e.g. CDK17/20/24) along with their accessories (such as imaging cameras, filter wheels etc).

HPS

All 10Micron GM mounts come with a feature called HPS – High Precision and Speed – an innovation from 10Micron. They feature traditional worm and wheel pairs, and with the latest state of the art encoder technology allows these mounts to perform at the same level of precision as professional direct-drive mounts.

The GM mounts utilise two high-precision proprietary (1/10th arcsec resolution) absolute encoders that are mounted directly on each axes. These encoders provide very impressive high precision GoTo pointing (typically to within 20 arc secs) and tracking accuracy (<1 arcsec).

The diagram above shows the 10Micron GM mount RA tracking error profile measured with an encoder coupled to the RA axis. To show how accurate the tracking is, Jupiter and its moon Ganymede are shown as they appear from Earth at the same scale in arc seconds.

The high-speed slewing of the mount, from 2 degrees to sprightly 20 degrees per second, is achieved using high performance servo motors.

Features

The Mount

The GM4000’s Right Ascension and Declination axes, both of which are made of alloy steel (for maximum rigidity) are 85mm in diameter for RA and 80mm for DEC. The axes are driven by two servo brushless AC motors, with a belt drive reduction with automatic backlash recovery that results in a backlash-free system. Both axes feature classic worm and wheel pairs. The worm wheels are made of (B14) bronze, with a diameters of 330mm (430 teeth) for the RA, and 244mm (315 teeth) for DEC. The RA and DEC worm is 32mm in diameter and both are made of alloy steel.

The mount features a dual Vixen/Losmandy type dovetail mounting saddle clamp. This allows the mount to have a wide compatibility with many telescopes from different manufacturers. Once you have mounted your telescope and equipment onto the mount, you can then use the electronic balance function to achieve perfect balance in both RA and DEC without unlocking the clutches. The mount also features internal cable routing for data and/or power to accessories (e.g. CCD camera) for no cable snagging or tangling.

The GM mounts can track 30 degrees/2 hours past the meridian and means that long duration astrophotography is easily achievable. The absolute encoders allow extremely high tracking accuracy (<1 arcsec), and means that autoguiding is not necessary. However, the GM mounts do allow the use of an auto-guider, if needed, through the inclusion of a standard ST4-compatible guide port.

Object Database

The built-in object database contains celestial objects from the major astronomical catalogues (e.g. Messier, SAO, NGC and more) down to 16th magnitude. The mount’s tracking rates are adjustable depending on the object being studied and the orbital elements of comets, asteroids and even artificial satellites can be loaded directly to the mount (without the need for an external PC), so that these celestial objects can be followed across the sky accurately.

Electronic Control System

A PC is not required to operate the mount as GM mounts can be controlled using the supplied weatherproof 4-line control handset keypad, with the computer’s electronic “brain” being housed in an independent portable external control box.

The handset’s display and the large ergonomic keypad (ideal for when wearing gloves), features a red backlight for ease of use in the dark. An internal heater keeps the handset display warm when the mount is being used at low-temperatures which allows for maximum readability in all temperature and lighting conditions.

The connectors of the motors, encoders, power and handset all use security lock screws for robust and secure connection.

Mount Control

If you wish to connect your own PC to control the mount, a WiFi, RS-232 or Ethernet connection is needed. The GM mounts can then be controlled using commonly available software packages via the proprietary 10Micron ASCOM driver (or Meade compatible command protocol). Included with the mount is software that creates a “virtual handset” on your PC with the same functionality and features as the physical hand set for easy (and familiar) control from your computer. Furthermore, the RS-232 port on the external can be utilised to control an observatory dome (and without a PC). The mount can also be parked in different user-defined positions in case of any internal “obstructions” and can also be switched on and off using the dedicated connector on the control box panel.  All these features help make the GM HPS mounts ideal for observatories and for remote operation.

Package Contents  

• GM 4000 HPS II Mount head with built-in precision absolute axis-encoders and WiFi option included
• Control box with onboard-intelligence Linux-processor, stand alone system V. 2 HPS version firmware
• 4-line key pad unit with graphic display and temperature control (#1452059)
• Counterweight bar with counterweight end stop
• Allen key set
• Power and connection cables
• USB stick with software and manual

Please note:

• In order to purchase the GM4000, mandatory shipping kit is required. This kit  comprises of the pier adaptor (#1454090) and the shipping crate (#2450010). The pier adaptor can be used to mount the GM4000 onto a customer or Baader pier.
• Counterweights, Dovetail clamp, pier adaptor and power supply are not supplied as standard with this package.

Specifications:

Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or sales@rothervalleyoptics.co.uk.

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.

The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

https://www.rothervalleyoptics.co.uk/zygo-tested-refractors.html

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email sales@rothervalleyoptics.co.uk.

Are you interested in this product but would like to speak to someone with some more information? Simply fill in the form below and we will get back to you as soon as we can!

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