Advanced solution for wide-field astrophotography.
Short 250 is an evolution of the classical Dall-Kirkham, to which a two-element corrector has been inserted, to allow the photography of weak objects with an intermediate focal length (f/7).
We have given the utmost care to the mechanical parts, to allow the maintenance of the optical axis and at the same time to allow the corrector to work properly.
Short 250 is a telescope with a classical Dall-Kirkham scheme (parabolic primary mirror, spherical secondary mirror), equipped with a generous two-elements corrector-reducer.
This instrument is designed and built to allow valid photographic sessions of mildly sized objects (such as galaxies, clusters, etc.). The very short tube and the low weight make the telescope easily transportable, and usable on a relatively small mount.
Nothing has been left to chance in the Short 250 design. All the metal parts have been made through numerical control with very strict tolerances, using aluminum alloys (anticorodal and ergal) and steel. All surfaces are protected with anodizing or chromium plating.
Particular care was given to the control of flexures and torsions of the optical tube. The high sensitivity of today’s sensors does not allow uncontrolled movements due to dilatation, flexion or torsion of any element of the optical tube.
The structure, made of rings joint by eight rods placed triangularly, is the one that gives the best optical and mechanical performances. The main concern in the project was to build a structure that would maintain the optical axis and the light cone where they should be, regardless of the position of the tube, the accessory connected to it, or the environmental temperature.
A very thin tube has been placed inside the carbon fiber structure, which sole task is to protect the optical set up from parasitic lights and dust. Three rear extraction fans will quickly bring the telescope in thermal equilibrium; this operation is made easier by low-expansion glasses and their low thickness. The lower the masses involved, the faster the attainment of the thermal equilibrium and, above all, the simpler it is to maintain it throughout the entire observing session.
Let’s point out all the precautions adopted in the Short 250, starting from the primary cell with 18 floating points on steel and teflon spherical junctions, to the primary mirror’s outer mask, to the regulation system of the primary and secondary mirrors through centesimal control systems, built in steel and implemented in supports based on technopolymer arranged in a matrix, designed to operate in any heat regime and even in the presence of dust. These regulation systems, combined with the mechanical precision of each individual component, will allow you to have your light cone in axis through minimal movements, easily manageable at the beginning of the observing session.
In the Short 250 there are no parts made in fusion, but only parts made from solid metal blocks, through the processing of suitable alloys with precision tools. The secondary mirror support consists of a centesimal system for the axial translation. The radial alignment – calculated in the assembly room – can be changed by the customer thanks to the adoption of a sophisticated tension system of the supports, which also allows their decentralization. The central block is supported by two brackets in tandem spaced by steel bars, to avoid any torsion in the secondary axis.
The customer can choose the preferred focus also according to the single and personalized request.
The instrument is supplied as standard with the 3” FTF motorized focuser, with MKIT 30 of the same manufacturer, except for different customer needs.
The carbon fiber tubes are made according to a precise project. They are not commercial tubes, but a proprietary project specially implemented by the MaxProjectTM Team on the NortheK Short 250. On the surface, they are rectified and coated with an anti-UV layer to better face the threats of the weather. The maximum load of the tubes is much oversized than required by the project. Feel free to place any accessory on them without fearing any kind of flexure.
The optics are made by Oldham Optical, from Scarborough (UK), with low expansion glasses and high surface accuracy (0,96 Strehl standard). The certificate enclosed with the telescope guarantees you purchased the best available in its price range.
Look at all the details and ask more questions, we will be happy to explain to you the high quality of precision and the refinement of the project of this Modified Dall Kirkham.
We are at your disposal to provide any further information; we will be happy to show you the high degree of precision and design refinement of this modified Dall-Kirkham!