AGEMA SD Apochromats: a line of Doublet Apochromatic Refractors with exclusive optical design, that provides spectacular high-contrast star and planet viewing with great color correction!
Optical Design: The objective of the Agema Apo is a fluorite-doublet featuring a glass-in-front combination. Putting the glass in front protects the fluorite from any external influences. Agema Optics use the highest quality optical materials for lens production, including glass that never undergoes secondary molding or annealing, and fluorite with optimal crystal orientation and uniform internal structure. Their complex lens cell eliminates the risk of deforming the optical components and protects them during telescope transportation. The cell design allows for fine adjustment of the lenses without disassembly — an important advantage. Agema use fluorite with unique dispersion properties, resulting in an optical system with a high chromatic aberration correction. The amplitude of residual deviation is 2.5–3 times smaller than the Abbe criterion for apochromatic lenses. The system’s Polychromatic Strehl Ratio exceeds 90% for the entire 430–700nm visual range.
By carefully selecting the glass and fluorite and using the refractive index data from the actual glass melt, Agema produce optics precisely fabricated according to calculated design. Their improved polishing process provides higher quality surface and in combination with low light scattering of fluorite it delivers excellent contrast images.
Each lens is individually controlled during manufacturing and again at final assembly. All optical elements have Broad Band Anti-Reflection coating.
Tube: The aluminum tube has internal baffles with knife edges that suppress indirect stray light. The tube is equipped with an extendable dew cap that reduces the entry of stray light and the chance of dew on the front lens. The inner surface is matte black; the exteriors are powder coated for a durable finish.
The focuser has 125 mm of travel and dual-speed operation with an approximate ratio of 1:10. The backlash-free motion mechanism accomplishes a reliably smooth operation you can count on. Fixing the movable tube in any position is achieved with the drum-type brake conveniently located directly on the pinion shaft. This prevents damage to the rack if accidentally forced without releasing the brake. The focuser has all the necessary adjustments, including friction control that provides the ability to support different equipment weights.
Our expert comment:
Agema has a waiting list for all of their refractors. The production starts only after a customer has registered on this list and remitted a 50% deposit prior to the order. The actual leadtime is currently uncertain and may take up to 1 year!
(Jan Ströher)
