Strength, Rigidity and Precision of Manufacture.
Maximising strength and minimising total weight has been an important aspect of the design process. The mount is at the limits of existing technology and materials use, whilst maintaining a reasonable asking price for product quality.

Thermal Mechanical Stability.
The basic design concept enables the Atika to be operated successfully over extreme temperature ranges and temperature gradients without affecting the performance or precision of operation. Estimated operating temperature ranges from minimum of -10 degrees Celcius to maximum of +50 degrees Celcius.

Forward Compatibility.
The overall basic design enables the mount and all options to be upgraded at any time as needed by the customer. It is therefore possible to purchase the mount with only basic accessories as needed at the time of purchase, bearing in mind that as needs and requirements increase further accessories can be purchased to increase the performance levels of the product. We expect that many new options will be made available in the near future so as to increase the versatility of the total product. Also, as technology develops in the industry in general newer and higher level options will become available.

Number of Options Available.
A significant number of options are available for both variants of the Atika. The choice can be made by the customer to suit particular requirements. If neccesary during the ordering process we will provide assistance with what is needed.

Number of Drive Controllers Available.
Both versions of the Atika are compatible with a number of drive controllers and total observatory systems offered by various manufacturers and depend on customer needs and requirements. The customer is not forced to purchase a proprietary drive controller, or any controller at all. During the ordering process Anssen determines the most suitable motor and gear reducer combination as needed by the customer.

Simple Operation.
Basic processes and operations are well laid out with simple manual access assuming that the majority of the use of the equipment is in total darkness and most probably with the operator wearing protective clothing. During both imaging operations and computer controlled operations it is entirely possible that the operator will rarely need to manually touch the mount which increases time management efficiencies and end image quality. We are aware that during imaging runs and surveillance operations every second can count.

Ease of Fitment and Interchange of Optical Tube Assemblies.
The general layout of the German equatorial mounting system permits a flexible arrangement of telescope payloads which are neccessary to many amateurs. Simple and straightforward design techniques of the Atika help accentuate the ease of fitting any number of optical tube assemblies up to the permssible maximum load capacity. It should be noted that although we advertise a maximum load rating in kilograms for each version of the mount these are only offered as a guide. There are many telescopes which are overly long relative to their weight and aperture and may overload the mount. Please contact us should you have concerns about this point.

  **Please note that traditionally Anssen has fewer teeth on the worm wheels than many of our competitors. High tracking accuracies are obtained (amongst many other reasons) with gears that are precision machined and precision ground and that are of large surface areas. A larger number of teeth is not required to achieve high resolution tracking performance. The accuracy, strength and shear loading is achieved with both relatively large surface areas and cross sectional areas of each gear tooth. A larger number of teeth result in smaller tooth size with smaller surface and cross sectional areas, hence weaker teeth.

Design and Manufacture Philosophies.

The Atika system enables optical tube assemblies to be carried very accurately and reliably. Several years of research have gone into developing the product. The mount offers easy use with a simple layout of features as well as a modern streamlined appearance.

The product is developed around the very rigid and compact precision cast aluminium RA and Declination housings, large RA and Declination shafts and tapered roller bearings. The vertical centre of gravity of the assembled mount with balanced telescope is centred within the vertical centreline of the pier so as to minimise the overhang and flexure of the instrument.

Extremely large junction surfaces where the Right Ascension housing meets with the altitude side plates, azimuth base meets the pier and the top of the Declination plate meets the telescope saddle promote maximum stability and minimum flexure.

All electrical wiring is fitted internally when the DC servo controller is optioned.

The counterweights are screwed on for the full length of the counterweight shaft. This feature permits very fine adjustments to the balance of the instrument, as well as guaranteeing that the counterweight cannot slip off the mount accidentally.

The bare mount has a compact overall height of 820mm from the underside of the base to the top of the Declination plate.

Right Ascension and Declination Housings

The RA and Declination housings are manufactured from precision cast aluminium and are completely machined all over.

The housings offer light weight but extremely high sectional rigidity despite heavy loading forces.

The critical dimensions of the castings, as with all of the machined components of the mount (unless otherwise stated) are manufactured to within 0.01mm tolerance.

Right Ascension and Declination Shafts

The high proportion of the mass of the Atika mount is found in the high tensile steel RA and Declination shafts which are 150mm in outside diameter and 90mm inside diameter. The shafts are stepped at each end to accept tapered roller bearings of 210mm outside diameter and 140mm inside diameter.

On completion of the machining processes the shafts are zinc dichromate plated to protect against corrosion.

Gearbox and Worm Housing Assemblies

The gearbox/motor/worm housings are finely machined black anodised aluminium components. Each housing is assembled with stainless steel socket head cap screws to add to the final appearance. The design of the housing promotes rigidity and compactness, whilst making the gearbox, stepper motor and worm very accessible. The entire housing can easily be removed from the mount for servicing and cleaning without removing the telescope, or the mount.

The design of the worm housing enables worm endfloat to be finely adjusted as required at any time. The housing also enables the worm wheel to worm clearance to be adjusted at any time.

The worm is accurately located at both ends by sealed bearing races.

Gears Worm Wheels

The RA and Declination worm wheel blanks are manufactured from high tensile aluminium which is anodised for protection against corrosion and also to promote final appearance. A finely machined phosphor bronze gear insert is then heatshrunk onto the worm wheel blank and re-machined. The gear teeth are then gear cut to finish the complete worm wheel. Machining accuracy is within 0.001mm tolerance then ground and polished to within 0.0001mm on all contact surfaces.

Worms

RA and Declination worms are stainless steel precision machined to within 0.001mm. The RA worm is then precision ground helically to within 0.0001mm. This ensures the highest possible tracking accuracy. Typical periodic error is less than +/-5 arc seconds without P.E.C. engaged.

Gearboxes

The gearboxes fitted as standard equipment are high precision planetary and rated to 12NM torque capacity.

Fasteners

Stainless steel fasteners have been used almost exclusively throughout the construction of the Atika mount. Stainless steel enhances the final appearance of the mount whilst ensuring a corrosion free operation when used in corrosive environments.

Painted high tensile steel socket head cap screws have been employed on highly stressed junction points such as the Declination housing to RA shaft and the Declination endplate to Declination shaft. Such use promotes high strength and rigidity, and reduces flexure.

Gear Clutches

The RA and Declination clutch system is integrated into the clutch assemblies. Eight grub screws are located radially on each clutch which adjusts the clutch tension from zero to fully locking. By use of the clutch system the telescope can be moved manually (ie manually pushed) into position by the operator and then fine adjusted via the electronics without the need to manually lock or unlock as a separate operation.

We do however recommend not to lock the clutch completely. If the clutch is completely locked and the telescope is accidentally bumped the shock can be transmitted through to the worm and gearbox causing possible damage.

Specialised Equipment

Anssen Technologies provides a specialised design and construct service for the supply of additional equipment such as telescope saddles, support equipment and accessories for most types of instrumentation. Please contact Anssen Technologies for further information.
Please refer to the Specialised Equipment page for further information.

 

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Last Revised: April 18, 2006.
Copyright © 2006. Anssen Technologies Ltd. All rights reserved.