Idai telescope refractor eyepiece lot .965" H20mm H8mm 2x barlow Moon filter

Description

This auction is for a lot of (4) .965-inch optical accessories that were stock to the 50mm and 60mm Idai Kimboshi-class refractors. This set is from 1987.
You will get:  (1) .965-inch H20mm eyepiece
(1) .965-inch H8mm eyepiece
(1) .965-inch 2x barlow with lower dust cap
(1) .965-inch top-fitting glass Moon filter
The Idai (Daiichi Kogaku) optical line is not very well known. In the late 1970s, they made the beautiful and rarely-seen #8803, which was a 80mm f/15 equatorial refractor with a lovely 40mm guide scope and a fancy 5x25 finder. Throughout all of the 1980s and maybe into 1992, they marketed the Kimboshi refractors, which came as 60mm f/13.3 equatorial or altazimuth refractors as well as a 50mm f/6 on an altazimuth mount. And toward the end of the 1980s, they made the Yozora, which was a 60mm f/6.9 master guide scope. It could also serve as a wonderful spotting scope or a small astronomical telescope.
Aside from these few telescopes, Idai also sold 1.25-inch kellners and plossls, which were sometimes offered as stock equipment on the later years of the Coulter Odyssey 8 and 10.1.
Below is a description of each item...
Barlow
5.58-inches long
18.2mm clear aperture
Coated Optics
The lower barrel and mid barrel are both aluminum. The uppermost barrel with the set screw is polyvinyl plastic. Inside retainers are aluminum.
Weighs exactly 1.7 ounces
This barlow has NO PROBLEM fitting into Japanese, Chinese, and Taiwanese mirror and prism diagonals for .965-inch barrels. It will fit in any .965-inch focuser barrel.
It will not fit into .965-inch diagonals or porro prisms that use a set screw-and-inner tension ring to hold the eyepiece. It will not fit into vintage thread-on porro prism units.
This has always been a good and trusty barlow of mine that I've used on a few public night venues over the years. Does wonderful, simple work in many of my 60mm to 80mm refractors by Jason, Celestron, Towa, Tasco, and Unitron. It will work fine in the USA-made Celestron C90s and Meade 97 Series maks. Will come to focus with most 3-inch to 5.5-inch reflectors with long-drawing focusers.
H20mm
Huygens 2-element with fully coated optics
Threaded to accept nearly any .965-inch color filter or Moon filter
35-degree field of view
Eye relief is comfortable and most will be able to leave their eyeglasses on
This eyepiece is unusually heavy for a beginner's eyepiece. The chrome barrel is brass, the internals are aluminum and polyvinyl plastics, and the upper black body is thick polyvinyl plastic. It weighs a dense 1.3 ounces.
A very good eyepiece to use in guider scopes, for solar projection projects, and it gives pretty sharp images in small refractors and cassegrains at f/12 or longer. It will give good images in refractors as short as f/10. Anything lower than that will add extra false color around bright contrasting objects as is the nature of the huygens and ramsden optical design.
H8mm
Huygens 2-element with fully coated optics
Threaded to accept nearly any .965-inch color filter or Moon filter
35-degree field of view
Eye relief is not too tight and equal to a 10mm plossl. It will be too tight for most eyeglass wearers
Like the H20mm, this one is also unusually heavy for a beginner's eyepiece. The chrome barrel is brass, the internals are aluminum and polyvinyl plastics, and the upper black body is thick polyvinyl plastic. It weighs a dense 1.2 ounces.
A decent high power ocular to use on the Moon's terminator or other regions when at half phase or smaller, inspecting Jupiter's (2) largest equatorial belts, it will spot Saturn's rings nicely and it did good on the Trapezium in M42 when at its highest angle in the sky. My Jason 313 gets along with this eyepiece nicely.
As with the H20mm, remember that huygens and ramsden oculars do not cooperate well in refractors or small cassegrains at under f/10. If you can, keep use these in a scope no shorter than f/11. F/13 is when images will get much sharper. At f/15 or longer, the images will greatly lose the false color fringing of purple and yellow around bright contrast objects. It is not that these are bad eyepieces. It is that you need to use them as they are designed to be used.
Moon Filter
Fits over the top of the eyepiece, does not thread in
True tinted Japanese filter glass
Tint is pale green with mainly gray color
This type of Moon filter is rarely found and I've only seen this also on an early 1970s Penncrest (Towa of Japan) 60mm equatorial refractor. To use the filter, simply place it on TOP of the eyepiece (above the part where you look in) and that is it. I have tested this filter to work with nearly all .965-inch eyepieces. It may not fit certain years of the Celestron (Vixen of Japan) .965-inch kellners as some of the focal lengths have a U-shaped caldera top.
The filter is made of pressed aluminum and filter glass. It is very lightweight at only 0.14 ounces.
Packed with great care.