Celestron AS and AS-GT mounts
The smallest large German equatorial mount from Celestron. Since the invention by Joseph von Fraunhofer of this type of mount circa 1810 it has been known worldwide as the 'German equatorial mount'. It is noteworthy that, over almost 200 years of use, almost nothing has changed in the design and nothing could be significantly improved. For astrophotography, the German mount is almost a 'must'!
The biggest advantage of the 'German mount' is its flexibility.
Unlike fork mounts, it is not limited to a particular telescope! Depending on your fancy, the air quality and the celestial target, you can attach a different OTA onto the same mount in a matter of seconds and balance it by moving the counterweights and telescope OTA so that the drive motors can very precisely compensate (precise enough even for photography) for the rotation of the Earth using extremely low power. Purchasing a Celestron AS (Advanced Series) telescope therefore always means getting an initial 'telescope-system' which does not have to be immediately extended with a mount and stainless steel(!) tripod.
Celestron AS mounts are characterized by their extremely high carrying capacity. Many amateurs use telescopes of up to 13 kg in weight on them without any tracking problems - even for astrophotography. The high rigidity of AS mounts is due to the very thick-walled cast aluminum housing and to the two large ball bearings on the (lower) so-called 'hour axis'. The size of the head bearing is that of a car's wheel bearing (to which it is very similar). The load carrying capacity also depends on the tripod construction. Heavy die-cast aluminium and stainless steel tubes give the height-adjustable tripod many times more torsional rigidity than the aluminum tripods that have often been used for this class. A metal accessory tray connected to the tripod legs absorbs vibrations most effectively and has room for up to five 1.25“ or 2“ eyepieces. Next to high stiffness and precision positioning, the most important thing is the combination of worm gear and worm wheel - which is actually the heart of the mount's drive. For the advanced mount (without GoTo electronics), this is a combination of bronze worm gear and aluminum worm wheel; an ideal solution for beginners who already want to use 'heavy equipment'.
In the AS-GT version, with GoTo electronics and NexStar hand control, both drive worms are equipped with ball bearings and meet all the needs of experienced astrophotographers, not least thanks to the sophisticated NexStar electronics, programmable hand-held controller, and sophisticated servomotor control electronics in the mount. The NexStar AS GT hand controller electronics are lacking in nothing. Celestron offers the 'PEC Tool' software for reducing worm gear periodic error (PEC). This is included with the Celestron NexStar GPS, CGE, and CPC models and is also adapted for the advanced GoTo scopes.
Standard equipment and accessories include:
- computerized German equatorial AS mount
- a precision worm gear on both axes of the AS mount for extremely uniform tracking and slewing
- generously dimensioned shaft and bearings and massive castings to give increased stability with the AS mount
- ultra-stable adjustable tripod with 51mm diameter steel tubular legs
- 2" focuser for use with 2" eyepieces with the C6-R, C6-R GT, C8-N, C8-N GT, C10-N, C10N GT, C80ED, C80ED-RGT, C100ED and C100ED RGT
- 'The Sky' level 1 planetarium software with approx. 10000 objects in the comprehensive database and with an improved display
The computerized GT models also offer:
- over 40,000 celestial objects in the database
- DC servo motors with encoders on both axes
- manual control unit with LCD display (2 lines, each with 16 characters), which is backlit in red to preserve dark adaptation
- PC communication interface in the hand control unit; extension socket and autoguider port on the drive motor
