127mm Fluorite apo

This project concerned the design and construction of a non-compromises high end quality aprochromatic refractor with regard to mechanical and optical quality.

The company Aries from Ukraine delivered the 5" APO objective. This fluorite objective is one of the best they ever made.

The optical tube assembly design has a number of remarkable features.

The tube itself is made from phenolic resin, very stiff and light. The inside of the tube is fitted with the necessary baffles. These baffles run from the start of the tube until the focuser and its accessories. This means that the the telescope is fully baffled until the edge of the field of view.

The dew cap can be extended als is also fitted with baffles as an entrance diaphragm.

The focuser has been derived from a Crayford design. The large heavy tube glides with 6 linear bearings over 3 polished shafts. This is a proven design in precision engineering.

The standard focus adjustment is with the generally used friction wheel drive. The fine adjustment for photography has been constructed separately and consists of a ring with fine thread inside its own linear motion guidance.

By using strong springs all free play has been eliminated.

This micrometrical fine adjustment can reproduce adjustment within 0.01mm very easily. The whole focuser can be rotated and removed. These features allow a very short telescope that can be easily transported.

The connection to various accessories is done with a separately designed ring dovetail construction. This eliminates possible tilting of the components under heavy loads. Many standard 2" adaptors suffer from this tilting problem.

Another benefit is that the components can be coupled very tightly.

Every possible accessory can be designed with this ring dovetail construction. In this way a large amount of possible configurations can be used.

A very unique feature is that all combinations are parfocal!