APM / Lunt 1.25" Herschel Prism without filters

APM / Lunt 1.25" Herschel Prism without filters

Herschel Wedge / Solar Prism with 1 1/4" barrel for professional solar photographie and solar observation.

Herschel wedges (solar prisms) are made for solar observation with refractors. Around 95 % of the solar light will be blocked. With a variable polarising filter and strong grey filters the sunlight will be reduced to the necessary amount. Unlike objective solar filters, the filtering happens close to the eyepiece or camera. Normaly the contrast and sharpness of the solar image with an Herschel wedge is much higher.

The advantages of the Lunt Herschel wedge:

Perfect surfaces for a very high contrast

Completely closed housing with integrated heat trap

No scattered light escaping, for maximum safety

Delivered in sturdy aluminium case with foam insert

Only for using with refractors:

The full solar energy enters the telescope and the filtering happens close to the focal plane, so we only recommend refractors for the working with the Herschel wedge. On the other hand, the refractor shouldn´t have a rear corrector lens. The optical elements would be heated through the concentrated solar energy and could be damaged. Also filters are only allowed at the eyepiece side of the Herschel wedge and not at the front.

Please note: Herschel prisms must therefore not be used on Petzval systems or other telescopes that have glass in the optical path near the focal point. Multi-lens systems do not pose a problem as long as all optics are only at the front of the objective.

The advantages of Herschel wedges at refractors:

In addition to the better image quality, the Herschel wedge offers more light. So you can use special contrast filter, like the Baader Solar Continuum. With filters like this you can increase the contrast at the sun.

Regulation of image brightness:

Of course 5% are too much for the solar observing. So you need an additional filter for light reduction. An ND3 Filter can be screwed directly in the eyepiece. Because the Herschel wedge produces polarised light, you only need a simple polarising filter to screw into the eyepiece or photo adapter for additional light reduction. Now you can rotate the eyepiece and so reduce the light. With additional grey filters and the Baader Solar Continuum Filter, you can reduce the brightness to the required amount and so affect the contrast.

Warning!!!

Never use the Herschel wedge without an ND3 and polarizing filter or Solar Continuum Filter!!! Otherwise permanent damage of your eyes may occur!!!

The ND3.0, polarizing filter or Solar Continuum filter are not included and sold separately!