Designed to accommodate large and small specimens, the National Optical 431-430PLL-20 40x & 80x Dual=Magnification Stereo Microscope makes it easy and comfortable for groups of people to share the view through the eyepieces.
Using a binocular head lets you view with both eyes open, which is not only more comfortable but preserves true 3D stereoscopic vision with a rich depth of view. The two eyepieces are set a comfortable 45° angle, and the eyepiece head rotates a full 360° circle so people standing or sitting at a table or desk can all enjoy the view without having to have everyone move to the eyepieces. Optically the microscope is outfitted with two 20x power eyepieces that, when combined with the 2x and 4x objectives, provide 40x and 80x magnifications. These relatively high magnifications are ideal for getting granular views of larger objects like rocks and gems, textiles, models, circuit boards, and artwork. The eyepieces are parfocal and parcentered, meaning they will require little or no focus adjustment when changing magnifications, so views remain sharp and they remain centered when the interpupillary distance is adjusted, ensuring clear and crisp views for every user at both magnifications. A diopter adjustment on the left eyepiece helps to compensate for individual eye strength and the eyepiece's interpupillary adjustment range makes it easy for all users to place their distance exactly where they need it. Finally, the eyepieces come with winged eyecups that block peripheral light; contrast and clarity are enhanced, especially in bright classroom or showroom settings.
The viewing head can be raised and lowered relative to the base for viewing flat or chunky specimens, with a maximum specimen height of 2.8" (7.2cm) and a working distance of 3.7" (9.4cm). The stage is integrated into the base to make viewing larger specimens like rocks, gems, textiles, and circuit boards easier. Upper and lower LED illuminators light the stage and independent power control allows you to have just the upper LED on, just the lower, or both. The upper LED also has its own rheostat dimmer to provide the right amount of light. The LEDs emit very low heat versus conventional incandescent bulbs, which will prolong the life of live material so you can have more time observing them in their living state. Two stage plates are included: a frosted glass that passes light without the harsh glare, and a reversible white/black contrast plate that provides a stark difference between your specimen and background to enhance the view.
- Two 20x eyepieces with 2x and 4x objectives produce 40x and 80x magnifications
- Quickly and easily change magnification by rotating the objective wheel 90°; wheel has positive click-stops to ensure it is optically aligned with eyepiece and specimen
- Winged eyecups block peripheral light to improve contrast while helping to minimize distraction
- Achromatic lens design virtually eliminates chromatic aberration, so colors are accurate and true to life
- Single speed rack-and-pinion focusing mechanism brings the view into sharp detail, with a slip clutch to prevent damage due to obstruction such as getting too close to the specimen stage
- Tension adjustment on the focus eliminates focus drift
Use and Handling
- Binocular design makes it easier and more comfortable to use versus monocular heads, while also preserving a true 3D view and rich depth of field when viewing rocks or gems
- Head set at a 45° angle to place user's head in a comfortable viewing position
- Head rotates a full 360° to make it easier to share with a group or class
- Wide 55-75mm interpupillary adjustment range accommodates a variety of users
- Runs on 110-240VAC power; supplied with a three-prong grounded US wall outlet plug
Specimen Stage & Illumination
- Stage is integrated into the base to provide a wide area for larger specimens like circuit boards, rocks, parchment, fabric, etc.
- Mount on post with locking support collar permits up or down adjustment of viewing head to accommodate different-sized objects on stage
- Frosted glass stage plate transmits light without harsh glare
- Reversible plastic black/white contrast plate enhances the view by providing a stark color difference between the specimen and the background
- Blue filter for transmitted light
- Locked-on stage clips hold specimen slides in place
- Upper LED illumination with rheostat dimmer
- Lower LED illuminator
- Independent control allows top or bottom illumination only, or both