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Never use the Vixen Sun Glass 31.7mm or Sun Glass 24.5mm for Solar Observation!

Vixen Sun Glass

Date : May 31 , 2012

The 31.7mm and 24.5mm Sun Glasses were light reduction filters to reduce light from the sun. These were produced and sold by Vixen as an item for safe solar observation. The Sun Glass was threaded into the eyepiece barrel directly and it enabled you to use the telescope for either visual solar observation or solar photography.

Although the 31.7mm and 24.5mm Sun Glasses themselves were proved to be safe from the light and heat of the sun if they were used properly, If any misuse of the product occurs, this could result in damage to your eyes (*1). As a result, since 1995 we have stopped offering the Sun Glass to our consumers as we, Vixen, believe that safety takes priority over all others.

In the past, we have included the Sun Glass in our optional accessories as an item for solar observation (*4) on condition that they should be strictly used together with a proper aperture limiting cap (*2), sun prism (*3) or alike. However, after further consideration, we decided not to recommend the Sun Glass for solar observation. Vixen maintains this policy and every owner of Vixen Sun Glasses are requested to follow this precaution.

*1 The sun is a very strong light source and there is danger of losing your eyesight if you look directly at the sun with your naked eye or through a telescope. If the Sun Glass is used, improper use or lack of the aperture limiting cap or sun prism could result in the Sun Glass breaking during observation.

At the present time Vixen recommends Sun Projection Screens only for observing the sun.

*2 The aperture limiting cap is a kind of lens cap that decrease the incoming light from the objective lens during solar observation. The aperture limiting cap reduces the effective aperture of the objective lens. Typically the incoming light is decreased to 4cm in diameter.

*3 The sun prism is designed exclusively for solar observation. More than 90 percents of the heat from the sun is eliminated. Safe solar observation is possible in combination with the aperture limiting cap and the Sun Glasses. These items are not available from Vixen at present.

*4 For reference only. (The description here shows the usage at the time Vixen supplied the product but the Sun Glasses are no longer recommended for solar observation.) How to use the Sun Glass safely
- Put the aperture limiting cap on the front of the telescope's objective lens to reduce the effective aperture and insert the eyepiece with the Sun Glass threaded into the visual back.
- If you have the sun prism and a dedicated sun filter for the sun prism, set the sun prism to cot out over 90% of the heat. Thread the dedicated sun filter into the eyepiece and then attach the eyepiece to the visual back.
Reduce the telescope's effective aperture with the aperture limiting cap if it is larger than 80mm in diameter. A combination of the sun prism and the Sun Glass makes a view of the sun very dim.