Skip to product information
1 of 4


A kit for changing the size of the microscope eyepiece (30mm) to that for astronomical objects (31.7mm, 1.25inch)

A kit for changing the size of the microscope eyepiece (30mm) to that for astronomical objects (31.7mm, 1.25inch)

Regular price ¥2,800 JPY
Regular price Sale price ¥2,800 JPY
Sale Sold out
Tax included. Shipping calculated at checkout.

This kit allows you to easily convert StarWorks' original high-end microscope eyepieces to astronomical eyepieces. In other countries, there are many amateur astronomers who only use microscope eyepieces, but in Japan, the advantages of microscope eyepieces are not so well known. Amateur astronomical eyepieces are not used by professionals, so their performance tends to be inferior.

On the other hand, high-end microscope eyepieces used in the professional world are very expensive when new, and are usually not sold on the market because they are originally included with the main body of the microscope, but you may be able to find them at a low price through second-hand auctions. There are many excellent eyepieces such as OLYMPUS, LEICA, NIKON, ZEISS, etc., which have the same focus in the entire field of view and no distortion, which is unimaginable in astronomical eyepieces.

Even the high-end astronomical eyepieces have a characteristic of high distortion and spherical aberration, although the chromatic aberration is at least reasonably good in the center. The astronomical eyepiece, on the other hand, has a larger image of the star and distorts as it moves toward the periphery.

What kind of eyepieces are suitable for astronomical use?

The best eyepieces are used in the high-end class of biomicroscopes (1.5-5 million yen class). This class is the infinity-corrected eyepiece that is often used by Nobel Prize class winners, but the best ultrawide (with a field of view of about 65 degrees) usually costs 80,000-180,000 yen. The next best are finite-corrected eyepieces for high-end stereo microscopes (¥500,000 to ¥1,500,000 class). High-end products for stereo microscopes with low magnification up to about 150x cost about ¥50,000.

Items below this are popular products for microscopes (e.g., for students), but generally have less distortion and coma than those for celestial objects. These lenses are very high-performance, but since they are not sold individually in Japan as they are overseas, most of them are sold at unbelievably low prices on Yahoo Auctions by industrial waste dealers who do not know their value. However, since many of these lenses are taken out of items that have been left out in the rain, you need to be prepared for the risk, but I think it is safer to use lenses that have once been in private hands rather than those of a vendor.

Creation Method

Most people wrap aluminum tape, but it does not look good and peels off quickly, leaving a messy residue. Overseas, conversion adapters are available, but they cost about 15,000 yen and are not very practical.

With the kit we have developed this time, you can create a beautiful sleeve at a small cost.

(1) Apply a single roll of sticker around the eyepiece to prevent it from slipping out.

(2) Insert the special cylindrical pipe into the eyepiece sleeve of the microscope.

(3) Heat the pipe with a hair dryer or heat gun, and the cylindrical pipe will contract to form a 31.7mm sleeve. This is a dedicated sleeve without the worry of it being rolled up or stained like aluminum tape.

If you wish to return it to its original shape, cut it open with a cutter.


This product cannot be used with the latest ZEISS eyepieces. The ring can be modified for aluminum as before. (¥5,000 for a fee) This kit is exclusively for microscope eyepieces with a 30mm sleeve. 23.2mm and 32mm microscope eyepieces are not compatible. Some bio-microscopes have an aberration eliminating eyepiece and objective settee. This is called a correction type eyepiece, but it cannot be converted to astronomical use.

View full details