iStar D180 F8-R30 (F1440) Doublet Objective Lens with Back Plate, Front Mounting Ring and machined lens cap. Includes Moonlite Focuser adapter (M100x1.5, for large format 2-1/2" focuser), two finder scope mounts with backing plates and two 235mm mounting rings. Focuser is not included.
This is going to make someone a wonderful instrument suitable for planets or deep space with a full 180mm aperture. The R30 designation indicates that the correction for chromatic aberration is equal to or better than a classic achromat with 30% longer focal length (ie.better than F8 x 1.3 = F10.4, or 1872mm).
The objective is of a high quality and was purchased directly from iStar Optical in Arizona, USA in 2020. This was one of their prototype D180/R30 objectives with a weight of 7.9Kg in mounting cell.
The lens has been manufactured using a heavy flint and special crown glass to achieve a high level of correction. The resulting lens is optically excellent.
The back plate and front mounting ring suit a rolled aluminium tube of 230.8 inside diameter x 1050 length.
Extensive construction notes and photos here:-
https://istarscopeclub.proboards.com...0-r30-build-oz
Post or pickup from Frankston South.
thanks for looking!
Graham
