Vixen SD81S II doublet apochromatic refractor telescope

The Vixen SD81S II apochromatic refractor is completely made in Japan and delivers an high quality SD doublet lens with 81 mm of aperture and 625 mm focal length (focal ratio F/7.7). You will find the best optical quality as usually delivered by Vixen along a sturdy yet ligh optical tube. Weight of the optical tube only is 2.3 Kg.

A new apochromatic refractor with high-performance Super ED Glass (=SD) made of leading-edge FPL53 glass reproduces extremely clear and sharp image by extraordinary eliminating color aberration.

The SD glass is designed to gather all g-ray (purple), C-ray (red), F-ray (blue), d-ray (yellow), and e- ray (green) around 0 value, which stands for an excellent lens material surprisingly reducing chromatic aberration over all colors. Using in combination with new optional SD Reducer HD Kit or SD Flattener HD Kit , it allows 44 mm image circle with full-format (D)SLR camera.

ED81SII, ED103S, ED115S were originally designed for both visual observation and photo visual users. SD Optical Tube Series optimized its position of "baffle" inside of draw tube in order to be compatible with full-size DSLR.

Features

• Optical Design: SD Apochromatic Refractor with S-FPL53 lens doublet (same optics as used in the former ED81S II)
• Aperture: 81 mm
• Focal Length: 625 mm
• Focal Ratio: F/7.7
• Coating: Multi Coating
• Resolving Power: 1.43 arc sec
• Limiting Magnitude: 11.3
• Light Gathering Power: 134x
• Back Focus (from rear edge of focuser body): 149.0 mm Back Focus
• Astrophotography: Prime Focus, Eyepiece Projection & Afocal Imaging
• Visual Back: 2" with compression Ring
• Optical Tube Length: 585 mm
• Optical Tube Diameter: 90 mm
• Outside Dew Shield Diameter: 100 mm
• Optical Tube Weight: 2.3 Kg (3.5 Kg with included accessories)
• Included Accessories: Tube Rings; Flip Mirror Diagonal; Dovetail Plate; Red Dot Finder; Carry Handle
• Made in Japan