Lunt 2" Solar Wedge (Herschel wedge) for refractors


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The 2" Lunt white light Solar Wedge yields the highest level of detail and contrast (both visually and photographically) of any white light solar filter available for refractors up to 150mm in aperture . . .
Our Product #: LS2HW
Lunt Solar Systems Product #: LS2HW
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Product Description

The Lunt 2" Solar Wedge (Herschel Wedge) is used to observe the sun in white light with refractor telescopes only, without using a filter over the objective lens. Unlike glass and film objective solar filters, the Lunt Solar Wedge does not selectively filter any of the visual wavelengths, thereby providing a true all-wavelength white-light view without the image degradation from the scattered light inherent in standard objective filters. Visual and photographic images through the Solar Wedge are noticeably superior in resolution and contrast to even the finest and most expensive glass and film objective solar filters.

The Lunt Solar Wedge uses a precision-polished wedge prism in a 2" star diagonal housing to deflect 95% of the sunlight away from the visual and photographic light path. The original 200 year old Herschel wedge prism design simply dumped the unwanted 95% of the light out through the underside of the prism housing (where the user had to be careful not to place any object or body part into this output beam to avoid burns). Instead, the Lunt design directs this unwanted light to a circular grating within the wedge housing, which scatters the energy within the housing's blackened interior. Vents at the top and bottom of the housing allow cooling air to flow through the housing to dissipate the heat from this scattered light. The circular grating (the red circle seen at the rear of the prism housing) will get hot during use, and care should be taken not to touch it during use and until it has had time to cool down after observing.

The remaining 5% of the light used for observing and imaging is reduced to the desired brightness level by a precision-polished neutral density filter permanently built into the wedge housing. Since the neutral density filter is always in the system, there is no chance of accidentally viewing the unfiltered light as with some other Herschel wedges. Because the Lunt Solar Wedge produces polarized light, Lunt recommends that you thread an optional polarizing filter into the barrel of your eyepiece for visual use. Rotating the eyepiece with the polarizing filter installed lets you adjust the image brightness to a comfortable visual level with larger aperture refractors.

The amount of sunspot detail and surface granulation will surprise even the most experienced solar observer. Penumbra resolve into a staggering array of fine wispy details with a wide range of contrast never visible with an objective filter. The solar disc is set against a jet-black sky, like observing the full moon at night. With the Lunt Solar Wedge, it becomes obvious that the lack of detail and contrast experienced with objective white-light filters was not so much due to the atmospheric seeing as you had thought, but rather due to the short-comings of the objective filter itself. There is no resolution or contrast loss across the full field during full-disc solar imaging and the image will not break down during high magnification visual observing.

Similar in length to a 2" diagonal, the Lunt Solar Wedge requires more back-focus than a 1.25" accessory. Since most 2" eyepieces have their field stops well below the main eyepiece body, however, most telescopes with 2" focusers will have no problem providing enough back-focus (in-travel) to use the Solar Wedge. Some telescopes, such as many of the TeleVue refractors, provide limited back-focus and this 2" Solar Wedge may not be usable with all eyepieces. In such cases, the 1.25" Lunt Solar Wedge may be a better choice.

CAUTION: Because the full energy and heat of the sun enters the unfiltered telescope aperture with this system, the Lunt Solar Wedge should only be used with air-spaced refractor telescopes under 150mm in aperture. In addition, the refractor must not have a corrector lens or lenses at the back, such as found in a Petzval-type scope. Optical elements like refractor corrector lenses or the secondary mirror of a reflector telescope become very hot from the concentrated unfiltered solar energy and can be damaged. The internal baffles and components of catadioptric scopes (Schmidt-Cassegrains, Maksutov-Cassegrains, etc) can likewise be damaged. Choose your telescope with care to avoid damage to the scope when using a Solar Wedge.

Likewise, care and common sense should always be used whenever observing the Sun. An occasional break from observing, with the scope turned away from the Sun, will give you and your scope a chance to cool down. Equatorially mounted scopes that are tracking the Sun automatically should not be left unattended when using a Lunt Solar Wedge.

Tech Details

Weight 24 oz.
Warranty 1 year


Review by:
This wedge is a great way to get your feet wet in the world of solar observing. It take a little time to learn how to find the sun during the day with a telescope since you cant look at it or use any stars for alignment. After that you get to work on your tracking. This was my first step and I've moved up to a Lunt 60mm solar scope. It's still nice to compare the views between the scopes. Highly recommended (Posted on 7/24/2019)
Review by:
This well designed and completely safe unit is the best for white light viewing. I always feared the over the aperture filters, as good they were, would either blow off, slip off or be pulled off by curious children at outreaches. This takes care of any concerns and the external heat sink does not get dangerously hot to the touch even after 2 or 3 hours long sessions. Warm yes, but not hot. I've used this with my ED80 and SV115 with excellent results. The granulation and penumbral sun spot detail is stunning. Razor sharp images. You will need to either buy the Lunt polarizer filter or use your own variable polarizer filter on the eyepiece as has been mentioned. The price is indeed quite a bit more when comparing to various solar films, etc. but it is still highly recommended for the best white light views you will ever see. (Posted on 1/13/2019)
Review by:
This Herschel wedge , along with a 5x powermate, allows for satisfying extreme solar close ups. Energy rejection was always very much under control and temp build up was a non-issue. I'm very happy with its performance and very solid build quality. (Posted on 11/3/2018)
Review by:
This Herschel wedge , along with a 5x powermate, allows for satisfying extreme solar close ups. Energy rejection was always very much under control and temp build up was a non-issue. I'm very happy with its performance and very solid build quality. (Posted on 11/3/2018)
Review by:
I have quite a collection of telescopes, and three of those are dedicated solar telescopes. Two are Hydrogen alpha and one is a CaK. Six of my night telescopes have front mounted solar rejection filters for white light viewing. However, I was looking for the ability to put several of my night sky refractors to use in my solar astronomy outreach. I purchased one of the Lunt white light solar wedges for use with my Orion 80ED refractor. I set up my refractor on an Ioptron Cube mount, installed the Lunt Herschel wedge in the focuser, and mounted a medium diameter eyepiece. A slow slew toward the sun, and I was able to easily put the view in the eyepiece. The first thing I thought was "Wow, this is bright!". And, it was. Even though the unit has a heavy filtration Neutral Density filter installed in the unit, the sun still puts quite a bit of light through to the eyepiece. Even though it was bright, I knew the concept of the Herschel Wedge is a sound one, and I had no concerns about the safety of the system. However, adding a 48mm rotating linear polarizing filter, green filter, or any kind of filter you want to the bottom of the eyepiece will give a more comfortable view. I usually use my Lunt Solar Wedge with a Green or Continuum filter to highlight the details that this wedge provides of the solar surface. I was so impressed with my first purchase that I bought a second one and I use it on my Astro Telescopes 152mm Refractor for a big solar telescope that allows me to filter the light however I please in the visible spectrum. The back of the Solar Wedge and a heat sink and disk that has warnings that it may get hot. I have never had my solar wedge get very hot. This is a wonderful piece of equipment, and I highly recommend it if you have a nice refractor of 152mm or less in aperture, and want to use your scope it the daytime on the sun, as well as the nighttime on the stars. (Posted on 8/4/2017)
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