photoinfos.com

Carl Zeiss Jena TM Parallactic Mount

Thomas Gade – April 2012

Description

TM Parallactic Mount

The mount features a synchronous motor on the right ascension axis operating at 220 volts and sidereal rate. Both axes have manual fine controls. Instead of worm gears, the fine adjustment uses push-pull rods with springs.

Without the motor, manual tracking is possible for about 30 minutes (approx. 7.5° per hour). The large setting circles are a standout feature, allowing easy location of objects when the mount is properly aligned. The telescope connects via the classic Zeiss prism rail.

Technical Specifications

Weight of axis cross	4.5 kg
Counterweight	2.5 kg
Payload	max. 8 kg
Connection	Clamping dovetail (Zeiss prism rail)
Manual tracking range	approx. 30 minutes (7.5° per hour)

Large setting circles of the Zeiss TM mount

Large setting circles

The TM comfortably carries conventional refractors up to 80 mm, lightweight ED refractors up to 100 mm, Maksutov telescopes up to 5" and SCTs up to 6".

For the Zeiss 63/840 and AS 80/840 refractors this mount is the ideal base. The longer AS 80/1200 reaches the reasonable load limit – longer vibration damping times must be expected.

Conclusion

The Zeiss TM offers excellent motor tracking and is easy to align precisely. The 220-volt power supply is usually readily available on balconies or terraces and more convenient than batteries and control boxes.

Manual tracking works well, though the limited adjustment range requires a suitable observing technique, which quickly becomes routine.

The mount is relatively compact and light for its payload capacity. Thanks to the moderate tripod leg spread, it fits through narrow balcony doors. For users who do not need GoTo or autoguiding, this classic Zeiss mount is an excellent choice in its class.