TS-Optics 121SDQ Apo 121 mm f/5.6 Quintuplet Flatfield Apo

The successful Flatfield Apo series from Teleskop-Service is complemented by this powerful 5-element apochromat. The apo is still transportable and is well supported by mounts like the Skywatcher EQ6, Celestron CGEM or the iOptron CEM40.

The field is perfectly flattened by the built-in corrector. You will have a perfect star image in the field right from the start, without the hassle of searching for correctors and the right distance. Although the apo has been optimized for astrophotography, it will also provide very good visual performance. The stars are crisp and are reproduced without chromatic aberrations. The image remains sharp and high-contrast up to approx. 350x.

The photographic 4" rack and pinion focuser:
The CNC focusert is optimized for photography and can hold a payload of up to 8 kg. The adjustment of the drawtube is carried out via a gear drive. In contrast to Crayford focusers, this focuser has an independent bearing system. This also guarantees sensitive adjustment at maximum load. In addition to 2" and 1.25" receptacles, an M82x1 thread (internal thread) is also available for screw adaptations. Suitable adapters, for example for the M68x1 thread, are of course available.

Features and benefits:

• Excellent FPL53 triplet lens (glass from Ohara, Japan)
• Integrated 2-element flattener with optimized distance to lens from factory for optimal field sharpness
• 4" CNC rack and pinion focuser
• The system is free of disturbing reflexes.
• Lens and corrector are adjustable - are delivered optimally adjusted

A first-class apochromat for astrophotography
Our goal was to achieve uncompromising image quality on the axis AND in the field without additional flatteners or correctors. The corrector must be permanently installed and, of course, at the optimum distance from the lens. This can hardly be achieved with an optional flattener. In addition, the apochromat must be mechanically solid and easily adjustable. This was achieved with the Flatfield Apo.

Thanks to the generous working distance of 125 mm from the 2" receptacle or 145 mm from the M82 internal thread, you can adapt any camera with filter wheels, off-axis guiders, etc. We will be happy to recommend the appropriate adapter rings and extensions for your camera and accessories.

So we pass each TS121SDQ to the amateur astronom:

• Every Apo is tested in the factory and delivered with a check protocol.
• Before shipping, every Apo is opened and completely checked in our technical department.

1. scope of delivery
2. cosmetics (e.g. dust on the lens)
3. optimal adjustment of the eyepiece extension


The successful Flatfield Apo series from Teleskop-Service is complemented by this powerful 5-element apochromat.