Products

Accessories: Binoviewer Model 24

This page under construction! This page originally described the first prototype of the Model 24 binoviewer. Updating will be done over the next few days to reflect the current production model features.

Te Burgess Optical Model 24 Binoviewer is a premium lightweight stereo binocular viewer adapted for use with telescopes. The redesigned Model 24 builds upon the previous Burgess Optical Binoviewers and offers premium enhancements.

The prisms in the Model 24 are still BaK-4, which is a distinct advantage for those with fast scopes. For the same reasons that premium binoculars use the more expensive BaK-4 glass in the prisms, we also use the same high-quality glass in our prisms. Now, our prisms are larger and oversized. That means there is no clipping of the light path. The prisms are silver coated to aid in reflecting and cutting down on unwanted light intrusions.

Features include:

• Oversized Prisms with 27mm faces
• 24mm Clear Aperture
• Silver Coated BaK-4 Prisms
• All Surfaces Fully Broadband Coated - the same coatings as used on the Paragon eyepieces
• Computer verified balancing of the beam splitter
• Dielectric Coating of Beam Splitter
• No clipping of the light path
• Self-centering eyepiece holders standard

With 24 mm of clear aperture, the Burgess Optical Model 24 binoviewer will not vignette any 1-1/4" eyepiece other than those with the largest field stops. The maximum field stop of any 1-1/4" eyepiece is 27mm and this limitation is based on the inside diameter of the 1-1/4" eyepiece barrel.

The prisms in the Model 24 binoviewer are larger than those previously offered. The picture at the right shows the new BV24 prism next to one from a Model C BV 125 binoviewer. As can be seen, the prism is longer and has a rounded end, compared to the cut-off end of the previous model. This translates into no light cut-off with a larger clear aperture.

The picture to the right shows the view through the left side of the BV24 binoviewer. The view through the right side is the same, except reversed. There are no obstructions in the light path. When viewed straight on, a perfectly round opening with 24mm of clear aperture is seen. The prisms and beam splitter are large enough to not obstruct the clear aperture of the binoviewer. The reflection outside the clear aperture seen in the photo is due to the lights used to take this picture.

All binoviewers use a beam splitter to divide the optical path to each eye. But, not all beam splitters work well. Some other brands of binoviewers have a green or blue tint when viewing through one or the other eyepiece holder. The color difference between the two sides is because the beam splitter is not passing the same intensity of light for all wavelenghts to each eyepiece. The beam splitter in the Model 24 is computer balanced and uses a dielectric coating to ensure that the same amount of light passes to each eyepiece for all visible wavelengths.

The eyepiece holders on the BV24 binoviewers have been completely reworked. The new eyepiece holders are made using the latest CNC techniques.

The new eyepiece holders are self-centering holders. The ring closest to the binoviewer body adjusts the focus for that eyepiece. The lower ring offers a diopter adjustment for each eye. The outermost ring is the clamping ring.

Also available as an option is a new CNC eyepiece holder with setscrews. The three setscrews are still there, but with thicker sidewalls, the screws are less likely to fall out when unscrewed too far. Shown are the optional brass setscrews. The BV24 comes with black Nylon setscrews to minimize scratching of eyepiece barrels. Also, the setscrews are positioned further down from the rim, thereby ensuring that the setscrews engage the safety undercut of the eyepiece barrel, if the eyepiece has a safety undercut.

The optional, setscrew-type eyepiece holders have a grooved ring with raised areas to aid in adjusting the helical focuser built into the eyepiece holder.

Included accessories

The Model 24 binoviewer includes the standard self-centering eyepiece holders. The self-centering eyepiece holders also fit our BV 125 binoviewers and are available separately.

The Model 24 binoviewer comes with an aluminum case with room for 6 filters in standard cases and 6 eyepieces. Also included are a 1.95x OCA and two 20mm BinoLite eyepieces.

The OCA screws into the bottom of the Binoviewer nosepiece. The OCA requires approximately 1/2" (12mm) of in-travel in order to reach focus. Included with the OCA is a parfocal ring for those cases in which the full insertion depth of the OCA extension tube is not required.

Use and Operation of the Binoviewer

Using the binoviewer is as easy as inserting the binoviewer nosepiece into where a 1-1/4" eyepiece would normally be inserted into the telescope. After the binoviewer is secured, insert a matched set of eyepieces into the eyepiece holder.

Enjoy two eyed viewing by focusing the image in one eyepiece in the normal manner. After that eyepiece image is focused, rotate the eyepiece holder of the other eyepiece to obtain focus in the second eyepiece.

A matched set of eyepieces is no more than just two eyepieces with the same focal length and of the same type, for example a pair of 17mm Plossel eyepieces. The helical eyepiece holders easily adjust for eyepieces of the same type that are not parfocal.

Merging Images: Each Burgess Optical binoviewer is tested by Bill Burgess for collimation before being shipped. A properly collimated binoviewer allows images to be merged easily when using an assortment of pairs of eyepieces.

Occasionally, the images seen in each eyepiece may not merge, that is, they do not appear as a single object when viewed with both eyes. This typically occurs when using short focal length eyepieces, which have a small exit pupil. Longer focal length eyepieces with their larger exit pupils typically allow merging with no difficulty. Merging problems also occur if the optical axis of the two eyepieces are not exactly parallel. If you encounter problems merging images, read our Binoviewer Merging page.

Reaching Focus: The Burgess Optical Model BV24 Binoviewer comes with a corrector (commonly known as an OCA - an Optical Corrector Adaptor). Without the OCA, the telescope focus tube needs to be racked in an amount equal to the optical length added by the binoviewer, which is about 4 inches (100mm), in order to reach focus. With the included OCA and extended nosepiece, only about 1/2 inch of in-travel is needed. Screwing the included OCA into the short nosepiece requires about 1 to 1-1/4 inch of in-travel. For more information, read our Binoviewer Focus page.

* To determine true clear aperture, measure the opening at the bottom of the eyepiece holder; however, caution must be exercised because there is optical glass immediately below that opening. Another method of measuring clear aperture is to direct a parallel light beam through the binoviewer and measure the diameter of the projected spot. Diverging light beams will give misleading results.

Available accessories include matching eyepieces, of which we have many to offer. Optionally available are the set-screw type holders that allow user collimation of the eyepieces. These eyepiece holders have been re-designed. They are CNC built and the 3 setscrews pass through a thicker wall and are less likely to fall out.

Price and Availabilty Information

Purchase Information