Microscopes, Stereo Microscopes, Refractometers, Polarimeters

Meiji Microscopes

2011-03-22T00:44:00.000-07:00

Meiji Techno Co., Ltd. is the third-largest manufacturer of optical microscopes in Japan. In 1964, Azuma Optics Co., Ltd. was founded as a contract manufacturer of microscopes and quickly established a reputation for high quality and fast delivery. In 1975, the company reformed into Meiji Techno Co., Ltd. and began selling microscopes directly to the public under the name Meiji Techno.

Originally a manufacturer of educational microscopes, Meiji Techno has since extended product lines into the industrial, laboratory, and higher education markets. Meiji products are sold throughout Europe, Asia, Africa and the Americas by agents or distributors authorized by Meiji Techno Co., Ltd., or the American subsidiary Meiji Techno America.

Some of Meiji’s product line includes stereo, compound, inverted, metallurgical gemological and video microscopes. It also offers an accessory selection that includes 35mm, video and digital cameras, filters, illuminators and many more options.

For many applications the ability to capture, display, and preserve specimen images is of equal or greater importance than actually viewing the specimen through the eyepieces. Photomicrography (35mm and other chemical formats) has been a common option on microscopes for decades, but the recent development of relatively inexpensive CCD (charged couple device) video and digital cameras has greatly increased both the popularity and flexibility of microscope imaging. Instead of clicking through slides during a lecture, university professors can now display real-time video images on projection televisions; petroleum geologists can e-mail images of core samples to their laboratories from remote locations around the world; oncologists can refer to CD or on-line catalogues of cell images to help them make faster and more accurate diagnoses. Whether your application calls for 35mm, large-format Polaroid, video, or digital imaging, Meiji Techno can provide you with the appropriate microscope and accessories.

Meiji Techno America was incorporated as a subsidiary of Meiji Techno Co., Ltd. in 1986, distributing Meiji Techno products and offering technical assistance to customers throughout the United States, Canada, and South and Central America. Originally located in Woburn, Massachusetts, Meiji Techno America moved to San Jose, California in December of 1991 and more recently expanded to a larger facility in Santa Clara, California as of January 2006.
Over the years, Meiji Techno America has developed a diverse network of over 240 knowledgeable dealers with expertise in many specialized applications.

No matter where you are located or what your requirements are, Meiji Techno has the products and expertise to help you attain your microscopy goals

Author Name: Rowland Brasch: Nationalmicroscope.com

Cleaning your microscope

2011-01-11T02:48:00.000-08:00

Customer often ask what they can do to keep their microscopes clean and in good working condition. Listed below are some questions raised along with our suggestions:

Question: What can I use to clean the lens on my microscope?

Answer: Lens cleaning fluids are the best. Use lens paper if available - the type for reading glasses works well. We suggest not using kleenex-type tissue as it is very "dusty" and will leave a lot of lint on the lens. Make sure the first tissue is wet with lens cleaner in case there are bits of glass from the slides on the lens that scratch it.

2. Question: What do I use to clean the body of the microscope?

Answer: We have tried many products over the years but have found that 409 cleaner seems to do the best job and does not damage the finish. Try not to get it into the bearings on the stage or focus assembly as it will dilute the lubrication.

3. Question: Lint seems to be a real problem on the eyepieces. How do I remove it without always having to use lens cleaner and papers?

Answer: Get some canned air from a computer or office supply store. Spray the compressed air at the eyepieces and that should remove most of the dust. Do not shake the can as you spray because you will cause the propellant in the can to come out of the nozzle and coat the lens. If you do, you will have to use the lens cleaner to remove this coating. Just hold the can still and spray. Remember that a lot of the particles you see on the eyepieces are from your eyes. They are flakes of dead skin that drop off your eyelids every time you blink.

4. Question: It is hard to see through the 40X or the 100X objectives. What could be the problem?

Answer: On most microscopes the 40X and 100X objective's front lens is slightly concave in design. This causes problems when users go to clean the objective. If you only use lens paper and cleaner you will not get to the contamination that has built up in the concave portion of the objective. Our recommendation is to use a soft cotton swab (Q-tip) to clean the objective. First, wet it with lens cleaner and make a soft drilling motion into the concave portion of the front lens. Next, use a dry swab and make the same motion to dry the lens. You may have to perform several repetitions of this procedure to truly clean the lens.

If this does not help then you may have oil inside of the objective itself, and it will either need to be sent to the manufacture for repair or you might have to replace the objective with a new one. The reason the oil penetrates the objective is due to either not cleaning off the oil after usage or leaving the objective in oil on the slide after reading it. Always clean the oil off the objective after each use.

Microscope Maintenance

2010-10-22T23:33:00.000-07:00

Customers often ask what they can do when they have problems with lubrication and focusing problems with their microscopes. Here are a few questions along with our suggestions:
Question: What product should I use to lubricate the bearings on the stage of the microscope?
Answer: Each manufacture has their own line of lubricants they recommend. If you bought everyone for each product it would be extremely expensive. We use a product called Super Lube made by Permatex. It should be available from many stores in your area. We use this product on all brands of microscopes that we service.
Question: My stage seems to slip down out of focus for no reason. What can I do to prevent this?
Answer: There are two main reasons for this problem. Either the tension control is too loose, or the main bearing system in the stage mechanics needs some adjustments.
You, as the microscope user, can adjust the tension control. Many microscopes have focus tension controls attached next to the coarse focus control. This control may be the simple type that you can adjust by just using your hand, or it may take a special tool. On Olympus or Nikon microscopes the adjustment is usually on the right side of the scope as the stage faces the user. It is a thin control knob or disc that is placed between the microscope stand and the coarse focus control. All you have to do is turn this device one way or the other and it will increase or decrease the tension on the coarse focus control knob. This in turn will keep the stage from slipping down. Make sure you are not turning the stage lock control, which is normally on the opposite side of the tension controller. If your microscope takes a special tool to adjust the tension. and you have lost this tool, you will need to contact the microscope manufacture or the company you purchased your microscope from and request the adjustment tool.
If the main bearing system needs adjustment you will should contact a qualified microscope repair technician to do this repair.

Microscope Immersion oil

2010-10-20T03:48:00.000-07:00

As magnification increases on a microscope the correction in refractive index is a requirement for finer resolution and brightness. As the light cone passes through the different layers of glass, sample mounting media and air light tends to bend at different angles. In most cases the sequence of the light leaving the substage condenser is glass (1.515nD), air (1.00nD), glass slide (1.515nD), sample, mounting media, cover slip (1.515nD), into the objective lens which is approximately 1.515nD.

Immersion oil has a refractive index of 1.515nD and is applied to the top of the cover slip and then the tip of the oil immersion objective is then immersed into the drop of oil. This completes the “optical connection”.

The resolution obtained is directly related to the angular aperture (AA), the larger the A.A. having a wider cone with more scattered (oblique) rays. Unless there is a homogenous light path, the most oblique rays are lost to internal reflection inside the glass slide or cover slip. The use of immersion oil permits full use of the resolving power of the objective lens. Immersion oil objectives increase the resolution by approximately fifty percent over dry objectives of equivalent focal length.

The resolving power of an optical system is figured by averaging the numerical aperture (N.A.) value of the objective and the working N.A. of the condenser.

The acid value of immersion oil should be very low. If not then the higher acid content can lead to eventual deterioration of the metal parts of the objective lens or worse yet the dissolving of the cements used to manufacture the lens. This is turn leads to a leakage problem as immersion oil is wicked up into the interior of the lens.

Viscosity of the oil is up to the user. Lower viscosities tend to run and spread all over the microscopes requiring more clean up. Higher viscosities are more practical and not as messy. Very high viscosities are used for instruments that are mounted on slight angles.

When applying immersion oil use only the amount required for the individual slide. Too much oil does not help with the optical performance as much as it requires more clean up. Not enough oil will not allow a good optical contact with the objective.

Which oil is the best? Our choice is Cargille Immersion Oil. It is manufactured with the best materials. Immersion oil must meet the design requirements of older microscopes and become the design criteria for new instruments.

Author Name: Rowland Brasch: Nationalmicroscope.com

ATAGO PRM-100a In-Line Refractometer

2010-10-13T02:51:00.000-07:00

The successful series of In-line digital refractometers by Atago Company LTD has added a new product, and it is being carried by National Microscope Exchange. The newly released ATAGO PRM-100a digital refractometer has replaced the popular older style PRM-85 and PRM-85SE instruments, which were a mainstay of the company for years. Atago Company is one of the most respected world leaders in manufacture of refractometer products according to National Microscope Exchange President Rowland Brasch.

“The newly designed PRM-100a In-Line refractometer continues on in the tradition of excellent ATAGO products which have made it a world leader in refractometry,” said Brasch. “The new ATAGO-PRM-100a incorporates the accuracy and ease of use found in the less expensive model CM-780N, but adds the features of a higher degree of accuracy along with the capability to measure refractive index as well as brix.”

The new PRM-100a In-Line refractometer has accuracy readings of +/- 0.05% brix and +/- .00010 for refractive index, and has two options for setting the minimum indication decimal place, as well as the ability to set a User-Defined Scale (input via RS-232C). This instrument is easily connected to your system by attaching the unit to a piping system to monitor food or beverage production, pharmaceutical production, industrial fluid, washing devices, dilution/mixing devices, etc. The in-line refractometer will continuously monitor water content and mixing ratio with successive measurements of refractive index, Brix, or concentration.

“ATAGO refractometers such at the PRM-100a are popular with users because of their accuracy and ease of use,” said Brasch. “The PRM-100a In-Line refractometer is more accurate than other ATAGO In-Line refractometers, making it more attractive to users.”

You can learn more about National Microscope Exchange products by visiting www.nationalmicroscope.com or by calling 800-851-7635.

Author Name: Rowland Brasch: Nationalmicroscope.com

Digital Microscope Cameras

2010-09-29T23:32:00.000-07:00

The successful line of digital microscope cameras by Vee Gee Scientific has added a new version of its H-Series to its VanGuard microscope accessory line., as carried by National Microscope Exchange. The newly designed VanGuard H-Series digital microscope camera system has replaced the popular older style H-series camera system, which was a mainstay of the company for years. VanGuard is a growing and respected importer of quality microscopes and accessories according to National Microscope Exchange President Rowland Brasch.

“The newly designed H-Series digital microscope camera system continues on in the tradition of excellent VanGuard products which have made it a leader in quality and affordable microscopes,” said Brasch. “The new H-series system incorporates the accuracy and ease of use found in the older style H-series which gives you the digital microscope camera, software, adapters and cables required to connect it to your computer.”

The H-Series digital cameras from VanGuard produce high-definition live images and video for the documentation and archival of clinical, life science, and material science laboratory analysis. With resolution of 1600 x 1200 (UXGA) and the included image capture software suite, the H-Series cameras are a perfect match for nearly any scientific application. Equipped with ½" CMOS image sensors, VanGuard H-Series digital cameras deliver exacting image clarity and color. In addition, H-Series digital cameras come standard with the following features: still & video capture modes, automatic/manual exposure control, manual gamma control, and automatic/manual white balance control.

“Vanguard products such at the H-Series digital microscope camera system are popular with users because of their accuracy and ease of use,” said Brasch. “The H-Series system is more affordable than some of the other products in the digital microscope camera product line, making it more attractive to cost-conscious users.

You can learn more about National Microscope Exchange products by visiting www.nationalmicroscope.com or by calling 800-851-7635.

How Polarized Light Works in a Microscope

2010-08-12T00:18:00.000-07:00

By Rowland Brasch

Normal light waves go in every direction. In a polarizing microscope the light waves are managed using two polarizing filters. One is called the analyzer and the other is the polarizer.

One way to understand how to create polarized light is to pass ordinary light, containing light waves that are vibrating in all directions, through thin slots cut in a piece of paper.

If the slots were aligned vertically then only the vertical light waves would pass through while the others would not. The vertical lights coming out of the slots are considered polarized light waves. These light waves in turn then illuminate the sample, usually crystals of some type. After passing through the crystal they are now out-of-sync because they moved at different velocities within the mineral. Once the light waves pass through the analyzer the colorations of the crystal provide identification of such samples.

Good examples of polarizing microscopes would be the Meiji ML9420 or the VanGuard 1242MM.

Most minerals are viewed where these polarizing filters are turned at 90 degree angles to each other. Polarizing microscopes are used to observe minerals and crystal formations. Applications can be in the clinical field for gout, law enforcement for drug analysis, industrial testing and geological applications.

Microscope Maintenance | Microscope Repair

2010-05-11T01:19:00.000-07:00

Customers often ask what they can do when they have problems with lubrication and focusing problems with their microscopes. Here are a few questions along with our suggestions:

Question: What product should I use to lubricate the bearings on the stage of the microscope?
Answer: Each manufacture has their own line of lubricants they recommend. If you bought everyone for each product it would be extremely expensive. We use a product called Super Lube made by Permatex. It should be available from many stores in your area. We use this product on all brands of microscopes that we service.

Question: My stage seems to slip down out of focus for no reason. What can I do to prevent this?
Answer: There are two main reasons for this problem. Either the tension control is too loose, or the main bearing system in the stage mechanics needs some adjustments.

You, as the microscope user, can adjust the tension control. Many microscopes have focus tension controls attached next to the coarse focus control. This control may be the simple type that you can adjust by just using your hand, or it may take a special tool. On Olympus or Nikon microscopes the adjustment is usually on the right side of the scope as the stage faces the user. It is a thin control knob or disc that is placed between the microscope stand and the coarse focus control. All you have to do is turn this device one way or the other and it will increase or decrease the tension on the coarse focus control knob. This in turn will keep the stage from slipping down. Make sure you are not turning the stage lock control, which is normally on the opposite side of the tension controller. If your microscope takes a special tool to adjust the tension. and you have lost this tool, you will need to contact the microscope manufacture or the company you purchased your microscope from and request the adjustment tool.

If the main bearing system needs adjustment you will should contact a qualified microscope repair technician to do this repair.

Author Name: Rowland Brasch: Nationalmicroscope.com

ATAGO Refractometers

2010-05-07T00:18:00.000-07:00

ATAGO Company LTD. is an ISO 9001 certified manufacturer, and has been the leading innovator in refractometer technology for over 70 years. The company has developed a full line of refractometers and polarimeters for measuring liquid concentrations in the lab, as well as a variety of hand held refractometers to use out in the field or on the production line. ATAGO refractometers and polarimeters can be found in over 155 countries, and are not only used in food and beverage industries, but also in research laboratories, universities, clinics and industrial settings.
The history of Refractometers began with a basic model – a simple analog instrument. Today, refractometers are highly sophisticated instruments due to the advancement of technology and the incorporation of high precision electronics into a refractometer.
ATAGO is constantly researching various and unique needs in the market, developing new and innovative products to meet the demands. In it’s quest for solutions to satisfy it’s customers needs, ATAGO continually strives to produce and bring to the market new instrumentation, which has never been seen or considered before through their in-depth research and development.

The USA office, located in Bellevue, Washington in the heart of the thriving Great Northwest, ATAGO U.S.A. is now in a better position to provide technical and sales support to all our valued distributors and end-users in North, Central and South America. ATAGO U.S.A. is committed to responding quickly and efficiently to every customer inquiry, and comprehensively researching their dynamic market place.

Author Name: Rowland Brasch: Nationalmicroscope.com

In-Line Refractometers

2010-04-06T00:55:00.000-07:00

In-Line refractometers are designed to monitor and control the concentration of dissolved solids or water soluble liquids in your process lines. These instruments can be incorporated in piping of manufacturing plants, liquid mixing devices, and washing apparatuses to continuously measure the concentration of various liquids. In-Line refractometers are suitable for use in the control of mixing, concentration, fermentation, and control of the concentration of water-based or alkali-based detergent, etc.

The light from an LED source is transmitted by a fiber optic onto one side of a measuring prism and internally reflected to the interface of the prism and the sample liquid. A portion of this light beam is reflected back onto the opposite side of the prism at an angle which depends on the refractive index of the liquid at the interface. The position of this reflected beam, as it exits the prism, changes with the angle of reflection (which depends on the refractive index of the sample). A linear diode array is used to accurately detect the varying position of the reflected beam, and this position is calibrated with respect to refractive index. As there are no moving parts with in-line refractometers, only precise optical and electronic elements, the calibration is very stable, repeatable and accurate.

To connect the in-line refractometer to your system you simply attach the unit to a piping system to monitor food or beverage production, pharmaceutical production, industrial fluid, washing devices, dilution/mixing devices, etc. The in-line refractometer will continuously monitor water content and mixing ratio with successive measurements of refractive index, Brix, or concentration.

The ATAGO Model PRM-100α In-Line Refractometer is just such an instrument. It can provide the following:

• Wide range 0.0 to 100.00% Brix range
• Improved measurement accuracy: Brix ±0.05%, nD ±0.00010
• Two options for setting the minimum indication decimal place
• Simple two-piece construction: detection section and operation display section
• Easy-to-read color display panel.

Author Name: Rowland Brasch: Nationalmicroscope.com

Antifreeze Refractometers

2010-04-03T03:16:00.000-07:00

Low temperatures leading to freezing conditions can, if not managed correctly, often result in serious damage to plant and equipment, chillers and engine cooling systems. System blockages, cracked pipes and unwanted fluid loss can be expensive both in terms of operational down-time and ultimate repair or replacement costs. It is therefore essential that systems are properly protected and antifreeze levels are periodically tested. Testing of antifreeze concentrations for automotive and industrial applications has been made easier by the use of antifreeze refractometers.

The antifreeze/battery refractometer is designed for testing the refractive index or concentration of battery fluids, antifreeze liquid and cleaning fluids that works on the critical angle principle. Antifreeze refractometers utilize lenses and prisms to project a shadow line onto a small glass reticule inside the instrument, which is then viewed by the user through a magnifying eyepiece.

In use, a sample is sandwiched between a measuring prism and a daylight plate. The reading is taken when a shadow line crosses the scale from the shadow line formed between the illuminated area and the dark area then a shadow line crosses the scale. With the indication of the percentage you may know which temperature the fluid will be frozen for both propylene glycol and ethylene glycol. It can also be used for checking the strength of electrolyte solution batteries.

Refractometers represent the most accurate conventional testing method available for determining freeze point and concentration of engine coolants and antifreeze solutions. Don't be misled by hydrometers or freeze-point test strips, which are not accurate enough to be useful.

One of the best instruments to test these solutions is the ATAGO Antifreeze Refractometer model Master BCF. This refractometer has an exclusive scale for measuring specific gravity of battery fluid and for checking the freezing temperature of ethylene glycol and propylene glycol which are used as antifreeze mixture in automobiles, thermal catalyst for solar power systems and other industrial applications. The Master BCF is easy to use and accurate for testing in the field

Author Name: Rowland Brasch : Nationalmicroscope.com

Inverted Microscopes

2010-03-16T01:06:00.000-07:00

Most microscopes that you see in a typical laboratory environment are compound microscopes. They are designed with objectives on a rotating nosepiece mounted above the stage, and the light source and condenser below the stage. They are most commonly used for viewing samples that have been fixed to a flat slide.

In certain applications it is necessary to look at live, unfixed samples. A more practical microscope design to use is the inverted microscope. An inverted microscope is a microscope with its light source and condenser on the top, above the stage pointing down, while the objectives and turret are below the stage pointing up. Inverted microscopes are useful for observing living cells, tissues or organisms at the bottom of a large container (such as a tissue culture flask). This allows you to examine the specimen under more natural conditions than on a glass slide, as is the case with a conventional compound microscope. You can place a Petri dish or other container on the stage and view the samples from below, thus not disturbing their more “natural” states. Larger, covered samples are less susceptible to evaporation and increases in temperature, thus preserving suitable living conditions for the specimen you are viewing.

Because of the fact that you have to look through thicker containers you often find the objectives to be long working distance or ultra-long working distance. These objectives have been corrected for observing samples that are further away than what you normally see on a compound microscope. The image may not be quite as clear as when you are looking at a perfectly flat slide. You may want to use a plastic Petri dish rather than a glass one as the plastic dishes are thinner and more uniform. Most inverted microscopes will have objectives that range from 4-40X, with 60X being an added option. You do not usually find inverted microscopes that incorporate 100X objectives.
Inverted microscopes can be configured for work in electrophysiology, in vitro fertilization, micromanipulation, high-resolution DIC, video-enhanced observations, and a variety of advanced fluorescence techniques. Motorized accessories can include shutters, filter wheels, revolving nosepieces, fluorescence block turrets, focus drives, and condensers. Inverted microscopes also allow you to add advanced objectives for water immersion, ultraviolet excitation, and phase contrast. Prices for inverted scopes vary according to the number and types of accessories you add to them, just as in compound microscopes.

The fundamental advantage of an inverted microscope is that it allows you to accept a container with a large and relatively long-lived diverse culture of live organisms without any preparation. This can be invaluable to work which requires the sample to be alive and in as natural an environment as possible.

Author Name: Rowland Brasch : Nationalmicroscope.com

Used Microscopes

2010-01-03T23:23:00.000-08:00

Remember back to your school days when you first saw amoeba swimming around in pond water? You thrilled to seeing the microscopic organisms moving around, bumping into each other. Now you want to share that memory with your children or grandchildren as they grow. But you don’t want to spend their college money on a new high-priced microscope, so what can you do? No problem – you can now find many microscopes that are either used or demo models at a much more reasonable price. But first you need to determine what type of a used microscope you want: compound or stereo/dissecting.

The most common microscope is the compound microscope. It is the one most people visualize when they think about microscopes. It comes with one eyepiece called a monocular; two eyepieces called a binocular or it might have an additional camera tube and is called a trinocular. It has a number of objectives (the lens closest to the object being viewed) of varying magnification mounted in a rotatable nosepiece. It uses a light source beneath the stage to illuminate slides. These microscopes are generally used to view very small objects such as cells or bacterium mounted on slides. Magnification of these scopes range from 40X up to 1000X. Actual magnification can be figured by multiplying the power of the eyepiece by the power of the objective lens.

The other type of microscope is called a stereo or dissecting microscope. It uses two eyepieces and two paired objectives. There are models that have full zooming capability and models that just have only two magnification settings. It is particularly useful for biologists performing dissections, technicians building or repairing circuit boards, paleontologists cleaning and examining fossils or any one who needs to work with their hands on small objects such as rocks & bugs. It may use a built in light source from above, below, or none at all. Magnification is usually from 10X to 40X.

By researching and purchasing used microscopes you open up a much greater range of instruments available to you. You can now purchase an instrument with many more accessories for much less money. Just make sure to do your homework ahead of time so that you know what to expect for the money you pay.

Author Name: Rowland Brasch : Nationalmicroscope.com

Abbe Refractometers

2009-12-29T02:33:00.000-08:00

Refractometers are measuring instruments which put the phenomenon of light refraction (bending) to practical use. They are based on the principle that as the density of a substance increases (such as when sugar is dissolved in water), its refractive index rises proportionately. Refractometers were devised by Dr. Ernst Abbe, a German/Austrian scientist in the early 20th century. The prism in a refractometer has a greater refractive index than the sample solution. Measurements are read at the point where the prism and solution meet. With a low concentration solution, the refractive index of the prism is much greater than that of the sample, causing a large refraction angle and a low reading. The reverse (lower refraction angle and higher reading) would happen with a highly concentrated solution.
Abbe Refractometers are a type of refractometer used for measuring the refractive index of solid samples, such as glass, plastics and polymer films. There are two detection systems for refractive index: transparent systems and reflection systems. Hand-held refractometers and Abbe refractometers use transparent detection systems, and digital refractometers use reflection detection systems. Abbe refractometer readouts can be either digital or analogue. Abbe refractometers are used most often to measure solid samples – something that standard digital refractometers cannot do. Circulating water baths can be added to control instrument and fluid temperature in Abbe refractometers.
Newer versions of Abbe refractometers have recently been upgraded to include solid state Peltier elements to both heat and cool the refractometer so that you no longer need to use a waterbath. Another modern feature is the ability to link the Abbe refractometer to a computer to control the instrument and to record readings. Some Abbe refractometers can measure at wavelengths other than the standard 589 nanometers, using filters on up to the near infrared range. They are referred to as Multi-wavelength Abbe refractometers. Multi-wavelength Abbe refractometers can be used to easily determine a sample's Abbe number, which is a measure of the material's dispersion (variation of refractive index with wavelength) in relation to the refractive index. These multi-wavelength Abbe refractometers can be used to test eyeglass lenses, contact lens materials, optical plastics for optical communication, compact disk materials and insulating oil. Other accessories that are available include digital printers, extra filters and near-IR viewers.

Author Name: Kathy Brasch : Nationalmicroscope.com

Brix refractometers

2009-12-14T23:47:00.000-08:00

You often hear the term brix and brix refractometer when testing samples for sugar content. Just what is a refractometer? A refractometer is an instrument that measures the refraction of light through a substance. The refractive index becomes higher in a substance of higher concentration.

A refractometer has a wide variety of uses such as measuring sugar concentrations and liquid concentrations. Refractometers are sometimes called “Sugar concentration meters” or “Density meters” depending on the application.
Brix and refractive index are common measurement scales for refractometers. A refractometer that measures brix is referred to as a Brix Refractometer. When measuring solutions that have multiple ingredients the Brix value equals the total concentration of dissolved solids.
About the Brix (%) Scale

Brix (%) shows the concentration percentage of the soluble solids content in a sample (water solution). The soluble solids content is the total of all the solids dissolved in the water, including sugar, salts, protein, acids, etc., and the measurement reading is the sum total of these. Basically, Brix (%) is the number of grams of cane sugar contained in 100g of cane sugar solution. When measuring a sugar solution, Brix (%) should perfectly match the actual concentration. With solutions containing other components, especially when one wants to know the exact concentration, a conversion chart is necessary.

Digital versus Analog Brix refractometers

Brix refractometers are available in hand-held (analogue) or digital models. Hand held units are read by putting a drop of sample on the prism, closing the daylight plate and then reading the scale through an eyepiece as the instrument is held up to your eye. A hand-held/analogue unit determines the refractive index or brix by use of the “Transparent System” which measures light as it passes through the sample and the prism. A low concentration sample has a larger angle of refraction so the boundary line falls on the lower part of the scale, whereas a high concentration sample has a small angle of refraction so the boundary line appears in the upper part of the scale.

Digital Brix refractometers use the “Reflected light system. When you put a sample on the prism and press the Start button, the light that is transmitted from under the sample will travel and refract in multiple directions. The angle of reflection is proportional to the refractive index of the sample, and the reflected light is measured by a sensor and converted into the refractive index or brix readout.

Because of their versatility, brix refractometers are used widely to test sugar content in fruit, vegetables, wine and other food products.

Author Name: Kathy Brasch : Nationalmicroscope.com

How a Polarimeter works: A more detailed explanation

2009-10-20T06:22:00.000-07:00

Light waves as it travels. As shown in Figure 1, light may seem to travel unidirectionally. In actuality light travels in all directions as shown in Figure 2.

When light, which waves in all directions, goes through a grating placed in its course of travel, only the light wave that oscillates in the direction parallel to the bars of the grating passes through, Light waves that oscillate in other directions get blocked by the bars of the grating. ( Figure 3 ) Such light, which waves in one particular direction, is called polarized light, and the grating is called a polarizing plate.

When polarized light travels through in a polarimeter an observation tube filled with a sample solution that does not make light rotate (water, for example), the light continues to wave in the same direction even after passing through the solution. ( Figure 4 )

In contrast, when it travels through in a polarimeter an observation tube filled with a sample solution that makes light rotate (sucrose solution, for example), the light wave begins to rotate as it passes through the solution. (Figure 5) This is called optical rotation.

Those samples that make light rotate have a molecular formula that contains asymmetric carbon ( indicated by "C" ) . Sugar is the most common. The explanation of the asymmetric carbon can be highly technical. Imagine making a light path by placing a polarizing plate, an observation tube, another polarizing plate, and a sensor one after another. (Figure 6 and 7). The path in Figure 6 has an observation tube filled with water, in Figure 7 a sample solution, such as sucrose solution, that makes light rotate, such as you would find in a polarimeter.

In Figure 6 a certain amount of light reaches the sensor.

In Figure 7 the light does not reach the sensor. (Technically speaking, in terms of a vector an imperceptible amount of light does reach the sensor, but let's assume that the light does not reach the sensor here. )

When the second polarizing plate is rotated as shown in Figure 8, the same amount of light as in Figure 6 now reaches the sensor.

Conducting Zero-Setting on a Polarimeter
Conduct zero-setting in the step shown in Figure 6. In the actual adjustment procedure, the observation tube filled with water is not necessary and zero-setting is conducted by letting light travel through the air. Next, place an observation tube filled with a sample solution that makes light rotate as shown in Figure 8. Rotate the second polarizing plate so that the equal amount of light reaches the sensor as it did when zero-setting was conducted. The measured angle of the rotated polarizing plate is the angle of rotation of the sample solution.

Author Name: Kathy Brasch : Nationalmicroscope.com

How A Polarimeter Works: The Simple Explanation

2009-10-20T06:18:00.000-07:00

Imagine tying a piece of thick rope to a hook in a wall, and then shaking the rope vigorously. The rope will be vibrating in all possible directions - up-and-down, side-to-side, and all the directions in-between - giving it a really complex overall motion. Now, suppose you passed the rope through a vertical rectangular hole, like this: []. The rope has a really tight fit in the hole. The only vibrations still happening at the other side of the hole will be vertical ones. All the others will have been prevented by the hole.

What emerges from the hole could be described as "plane polarized rope", because the vibrations are only in a single (vertical) plane. Now look at the possibility of putting a second hole on the rope. If it is aligned the same way as the first one, the vibrations will still get through. But if the second hole is at 90° to the first one (so horizontally), the rope will stop vibrating entirely to the right of the second hole. The second hole will only let through horizontal vibrations - and there aren't any.

Light is also made up of vibrations - this time, electromagnetic ones. Some materials have the ability to screen out all the vibrations apart from those in one plane and so produce plane polarized light. The most familiar example of this is the material that Polaroid sunglasses are made of. If you wear one pair of Polaroid sunglasses and hold another pair up in front of them so that the glasses are held vertically rather than horizontally, you'll find that no light gets through - you will just see darkness. This is equivalent to the two holes at right angles in the rope analogy. The polaroids are "crossed". (This not exactly the way Polaroid glasses work, but it gives a good idea).

A polarimeter works the same way: You have two polaroid glasses, like the two holes with the rope, one glass is the polarizer, the other glass is the analyzer. The polarizer ensures that only a beam of polarized monochromatic light (light of only a single frequency - in other words a single color) is passed through the solution behind the polarizer in the polarimeter. After the tube with the solution is the analyzer. The polarimeter is originally set up with water in the tube. Water isn't optically active - it has no effect on the plane of polarization. The analyzer is rotated until you can't see any light coming through the polarimeter. The polaroids are then "crossed".

An optically active substance is a substance which can rotate the plane of polarization of plane polarized light. If you shine the polarized monochromatic light through a solution with an optically active substance, then light emerges: its plane of polarization is found to have rotated. The substance rotates the plane of polarization of the light, and so the analyzer won't be at right-angles to it any longer and some light will get through. You would have to rotate the analyzer in order to cut the light off again.

The rotation may be either clockwise or anti-clockwise. Assuming the original plane of polarization was vertical, you can easily tell whether the plane of polarization has been rotated clockwise or anti-clockwise, and by how much.

Author Name: Kathy Brasch : Nationalmicroscope.com

Principals of Refractometers

2009-10-20T06:07:00.000-07:00

Water is placed in a reservoir. When a pencil is dipped into the water, the tip appears bent. Now put concentrated sugar water into a cup and try the same thing. The tip of the pencil should appear even more bent. This is the phenomenon of light refraction. Refractometers are measuring instruments in which this phenomenon of light refraction is put to practical use. They are based on the principal that as the density of a substance (e.g. when sugar is dissolved in water), it's refractive index rises proportionately.

When a straw is placed into a glass of water, the straw appears bent. Now if a straw is placed in a glass with water containing dissolved sugar, the straw should appear even more bent (see illustrations). This phenomenon is known as the principle of light refraction. Refractometers are measuring instruments which put this phenomenon of light refraction to practical use. They are based on the principle that as the density of a substance increases (e.g. when sugar is dissolved in water), its refractive index (how much the straw appears bent) rises proportionately. Refractometers were devised by Dr. Ernst Abbe, a German/Austrian scientist in the early 20th century.

The prism in refractometers has a greater refractive index than the sample solution. Measurements are read at the point where the prism and solution meet. With a low concentration solution, the refractive index of the prism is much greater than that of the sample, causing a large refraction angle and a low reading. The reverse (lower refraction angle and higher reading) would happen with a highly concentrated solution.
There are two detection systems for refractive index: transparent systems and reflection systems. Hand-held refractometers and Abbe refractometers use transparent systems, while digital refractometers use reflection systems.

Transparent Systems
The detection system for hand-held refractometers (transparent system) is summarized below.
1. In the figure below the detection is done by utilizing the refractive phenomenon produced on the boundary of the prism and sample. The refractive index of the prism is much larger than that of the sample
2. If the sample is thin, the angle of refraction is large (see "a") because of the large difference in refractive index between the prism and the sample.
3. If the sample is thick, the angle of refraction is small (see "b") because of the small difference in refractive index between the prism and the sample.

Reflection Systems

In the figure below, Light A, being incident from the lower left of the prism, is not reflected back by the boundary, but exits through the sample. Light B is reflected by the boundary face to the right, directly along the prism boundary. Light C, having an incident angle too large to be let through to the sample side, is totally reflected toward the lower right of the prism.

As a result, a boundary line is produced dividing light and dark fields on either side of the dotted line "B' " in the figure. Since the angle of reflection of this boundary line is proportional to refractive index, the position of the boundary line between light and dark fields is caught by a sensor and converted into refractive index.

Author Name: Kathy Brasch : Nationalmicroscope.com

Choosing A Microscope: Compound or Stereo microscope?

2009-10-20T05:56:00.000-07:00

Your application is the most important factor in choosing a microscope. What you need to see and what you want to do with that image will determine what kind of microscope you need. Microscopes typically come in two types: compound or stereo microscope.

The most common is the compound microscope. It is the one most people visualize when they think about microscopes. A microscope with one eyepiece is called a monocular microscope; with two eyepieces it is called a binocular microscope, or it might have an additional camera tube and is called a trinocular microscope. The compound microscope has a number of objectives (the lens closest to the object being viewed) of varying magnification mounted in a rotatable nosepiece. It uses a light source beneath the stage to illuminate slides. These microscopes are generally used to view very small objects such as cells or bacterium. Magnification of compound microscope scopes range from 40X up to 1000X. Actual magnification can be figured by multiplying the power of the eyepiece by the power of the objective lens.

The other type of microscope is called a stereo microscope or dissecting microscope. It uses two eyepieces and two paired objectives. Stereo microscopes come in models that have full zooming capability and models that just have only two magnification settings. Stereo microscopes are particularly useful for biologists performing dissections, technicians building or repairing circuit boards, paleontologists cleaning and examining fossils or any one who needs to work with their hands on small objects. You can find stereo microscopes that have a built in light source from above, below, or none at all. Magnification is usually much less than that of a compound microscope, but is figured in the same way by multiplying the power of the eyepiece by the power of the objective lens.

Author Name: Kathy Brasch : Nationalmicroscope.com

Digital Microscope

2009-10-09T05:24:00.000-07:00

A digital microscope is real 21st century advancement on microscope technology. It comes with software for your computer that allows you to see real-time images on your monitor of what you're observing with the microscope. Take a step into the modern age by learning how to use a digital microscope.

With the advent of computers and the digital era things have improved a lot. You can now buy a handheld digital microscope from the market at affordable prices which will plug straight into the USB port of almost any computer, and displays and records the image in real-time. A digital microscope still uses optics much the same way as a traditional microscope, but also has a built-in digital camera, which works just like a webcam but with magnification. The software that comes with these cameras will let you take still or video pictures while magnifying the image by 200 times or more. You can then use your regular image software to manipulate and use the picture in many ways.

Although these digital microscopes are obviously great in a science classroom environment where a teacher can present and discuss a rapid sequence of images, don't neglect their home use. Digital microscopes offer an amazing insight into the world around us from a rarely seen perspective.

Digital microscopes were brought to a new level of excellence with the introduction of Olympus' MIC-D. The MIC-D uses a USB connection to the computer for live, full-color images to be displayed on a monitor screen. The design of the MIC-D is inverted, which means that the lens is tilted up at the stage instead of positioned down at the specimen. This feature allows large objects and dishes of water to be magnified with amazing clarity. A further innovation of the MIC-D's design is that it uses one master lens instead of a series of fixed lenses.

Author Name: Kathy Brasch : Nationalmicroscope.com

Stereo Microscope

2009-09-30T00:34:00.001-07:00

A stereo microscope is used for comparing two side-by-side specimens. It consists of two regular microscopes connected together with an optical bridge. They are commonly used in fields such as forensics, where fingerprints, DNA or a sample must be compared in great detail to another. A stereo microscope provides the viewer with an upright and laterally correct image as opposed to the upside-down and backwards image that a compound microscope provides. The stereo microscope also has a greater distance in most cases between the stage and the objective, so that the specimen can be worked on or dissected while it is being viewed.

The stereo microscope, by virtue of its twin eyepieces, allows you to view your specimen with both eyes and get a much more accurate view of its surface. The human visual system only perceives depth accurately when both eyes are viewing an object, so using a compound microscope with one squinting eye can produce a distorted idea of what is actually being seen.

The stereo microscope also has two magnification systems: fixed and zoom. Fixed magnification is achieved using a pair of objective lenses with a set magnification degree. Basically, the degree of magnification that you get solely depends on what your lenses are capable of.

Stereo microscopes are also capable of digital displays, as in the case of digital microscopes. Having the image projected on a high resolution monitor is very useful especially in surgeries. Microscopes have truly gone a long way. Previously, only one lens is used; today, microscopes with two optical paths are in existence.

Zoom magnification, on the other hand, allows the user to use varying degrees of magnification. Have you ever heard of the terms "zoom in" and "zoom out?" Stereoscopes with zoom magnification are capable of handling slide-prepared specimens. The versatility of a stereo zoom microscope means that you’ll never be without a way to study whatever catches your eye.

Author Name: Kathy Brasch : Nationalmicroscope.com

Microscope Camera

2009-09-22T06:00:00.001-07:00

The digital microscope camera is an amazing thing of modern science. A digital microscope consists of a regular microscope with a digital camera built into it. The images seen through a digital microscope can be projected to a computer monitor and saved on a computer file. A digital microscope is perfect for education because it lets many people view the specimen at once. The data saving capabilities of a digital microscope make it a great tool for research.

A wide range of microscope cameras are available in the market like cmos digital camera, ccd digital cameras, slr camera and video cameras online. These microscope cameras are useful for many purposes. Meiji and VanGuard are two of the big brands for microscope cameras. When a microscope camera is added on digital microscope, extensibility and uses of the microscope increase. This device is ideal for anyone using a microscope. Most digital microscopes connect to computers via a USB port. Once the microscope is connected to the computer, the images seen through the microscope’s eyepiece can be shown on the computer’s monitor and saved on the hard drive for future use. Images can be printed if the computer is equipped with a digital printer.

A wide range of microscope camera accessories are available in the market to increase its capabilities. A microscope camera is very useful for education, research, medical and many other science applications. A microscope camera is connected to the eyepiece of the microscope. The digital camera can be used in a wide variety of ways, and adds a higher degree of function to your microscope.

Author Name: Kathy Brasch : Nationalmicroscope.com

Trinocular Microscope

2009-09-15T23:14:00.000-07:00

A Trinocular microscope is virtually the same as a binocular microscope but adds a third eyepiece tube. Trinocular microscope models have two eyepieces for normal viewing, plus a third "phototube" on which you can mount a camera without interfering with the normal operation of the microscope. No, it's not for people with 3 eyes, but for people who wish to attach a camera to the third eyepiece and be able to photograph or video what they can see through the two eyepieces. You should consider purchasing a trinocular microscope if photography is needed option.

There are many different methods for capturing, displaying, and recording microscope images, and each has its own advantages and disadvantages. It would be impossible to cover all of these options here but access to these options is important in selecting your microscope. It is possible, but not practical to mount a camera on a monocular or binocular microscope.

A trinocular microscope may be an optical, acoustic, or an electron microscope. In other words, it may be a microscope in which the specimen is illuminated by visible light, by sound, or by a particle beam of electrons. The third eyepiece can also be added to a stereo microscope. A binocular compound microscope uses one lens array for the objective but has a pair of eyepieces, with the light from the image formed by the objective split by a prism.

A trinocular microscope has one of several purposes. One purpose is to allow a second viewer access to a specimen at the same time as the person who is mainly using the microscope. Another purpose of a trinocular microscope is to allow the use of technology to either preserve the images seen through the microscope by recording them or projecting them.

We start with the premise that choosing a microscope should be an enjoyable process! There are a number of variables that go into selecting any kind of microscope system like a trinocular microscope, monocular or binocular microscope. The process can be a little daunting. Moreover, there is a bewildering range of quality - from cheap plastic microscopes to the most expensive German and Japanese brands.

Microscopes are configured to suit different applications. It is important to ensure that you purchase a microscope that is well-suited to your application.

Author Name: Kathy Brasch : Nationalmicroscope.com

Microscopes - Polarizing Microscopes

2009-09-09T04:30:00.000-07:00

A polarizing microscope is a scientific instrument used to make optical measurements. Polarizing microscope is a special kind of microscope that utilizes two polarizing lens to acquire data from the specimen. The polarizing microscope is used extensively in the field of optical mineralogy which supports such applications as geology, asbestos testing, and forensic science. Often those working in different fields will sometimes refer to the polarizing microscope by different names such as geology microscope, petrographic microscope and pol microscope.

Polarizing microscopes can be used to measure various optical properties of a material, including linear birefringence, circular birefringence, linear dichroism, circular dichroism and scattering. To measure these various properties, there have been many designs of polarimeters. Some are archaic and some are in current use.

The key difference between the polarizing microscope and a standard compound microscope is the addition of a fixed polarizer between the light source and the specimen and the addition of an adjustable polarizer between the objective and the eyepieces. The second polarizer is called the "analyzer" and usually can be inserted in and out on a rotating piece in the neck of the microscope. Other common accessories include a rotating stage and insert able retardation plates made from gypsum or quartz.

The first use of these kinds of microscopes over one hundred years ago was for the identification of minerals in geology. In addition, the most common form of lab analysis to test for asbestos is performed with a polarizing microscope. Because of their ability to provide optical data, these kinds of microscopes are very commonly used in forensic science where the identification of unknown materials is a routine part of the job.

The polarizing microscope is a very versatile and powerful instrument in the identification of materials and provides the very accurate results. It is a key tool in several scientific fields, and can sometimes be the best option over more expensive technologies. The polarizing microscope is a very cost effective instrument for research and analysis industry and you can buy it online through our webstie e-store.

Author Name: Kathy Brasch : Nationalmicroscope.com

Binocular Microscope

2009-09-09T04:22:00.000-07:00

A Binocular microscope is a compound microscope. The binocular microscope is simply a microscope that lets the viewer use both eyes. The three-dimensional image makes manipulating or dissecting specimens easy. The two optical pathways each give a slightly different image to the eyes, and the brain converts this to show a solid object magnified a few times.

Every binocular microscope has four main parts - the base, the stage, the arm, and the stage adjustment knobs. The base is the overall foundation for the binocular microscope. It is purposely heavy to prevent it from falling over. Various materials are used to give it so much weight.

The stage is the the platform upon which you place the specimen you are viewing with the binocular microscope. A light is underneath the stage so that you can have all the lighting you need to view the item properly. The arm is connected to the base and it is in the form of an "L". To move a microscope you normally hold onto the arm with one hand, placing the other hand under the scope. There is an obtuse angle at the end of the joint.

When it comes to operating a binocular microscope you will find some differences over other types of microscopes. You want to have the stage magnification at the lowest possible setting before you place the sample onto the stage. This will offer you the broadest view of the sample and prevent the lens from getting scratched. You should also use the focal lens with your dominant eye to get the best view. You can then move the spinning nosepiece to look through higher magnification objectives for more detail.

A binocular microscope can also be a research microscope. The newest form of the binocular microscope is very similar to oldest form in which two completely separated tubes were employed. This type of microscope is the most advanced most people will ever see, much less ever use.

Author Name: Kathy Brasch : Nationalmicroscope.com

Microscope Accessories

2009-09-06T23:10:00.000-07:00

It is an established fact that microscopes have so many uses in many different industries that the accessories that go with these devices go unnoticed. The excitement of using your very first microscope could be more mentally and visually stimulating when the right accessories are used to prepare and study varying species of plants or animals. There are many microscope accessories or items that make studies and observations much more meaningful. Most of them enhance the scrutiny of the specimen or subject while some are there to make the study much more exciting.

Microscope accessories can be categorized by age level. Some ‘kits’ are for students while others are to be used by scientists and other professionals. There are numerous online stores that sell these microscopes accessories.

Microscope accessories include boom stands, carrying cases, dust cover, microscope books, and eyepieces. It is quite easy to purchase a microscope accessory from the store and use it conveniently according to your need. Microscope accessories can be different according to the model of microscope like microscope cameras, polarizer, refractometers, stereo microscopes, binocular microscope, monocular microscopes, dissecting microscopes and many other microscope models.

These are many different microscope accessories available in the market or on the online store. It is best to get all of them needed for a particular application so that the functionality of the device is maximized.

Author Name: Kathy Brasch : Nationalmicroscope.com

Refractometers

2009-09-04T00:48:00.000-07:00

A refractometer is a laboratory or field device for the measurement of an index of refraction.

Refractometers have been thoroughly adopted in agriculture and in food and beverage is a common abbreviation in the United States.

A Refractometer is a precision tool used to measure salinity. Serious hobbyists know that the best way to measure the salinity and specific gravity of aquarium water is to use a refractometer. These precision optical instruments are incredibly accurate even at very low salt levels, and are equally easy to use. Recently, these instruments have become more affordable, so now every aquarium owner can have one to help monitor water conditions.

The Abbe refractometers sold today operate similarly to their predecessors, using the density of a sample to determine its refraction, in physics, deflection of a wave on passing obliquely from one transparent medium into a second medium in which its speed is different, as the passage of a light ray from air into glass. Digital refractometers, the other major bench-top format, reflect light through a prism toward a sample and find the angle at which it refracts and reflects onto the same line.

High performance automatic refractometer offers advanced features associated with the world's best refractometers, such as a secure data storage card, custom programming of concentration scales, highly durable touch screen controls, keyboard lockout security feature, and interfacing with polarimeters.

Author Name: Kathy Brasch : Nationalmicroscope.com

Microscopes

2009-09-03T11:19:00.000-07:00

A microscope is an instrument for viewing objects that are too small to be seen by the naked eye. The science of investigating small objects using such an instrument is called microscopy. The term of microscope means to see very small, not visible with the eye unless aided by a microscope.

Microscopes are very essentail for today's life. You may find a variety of microscope models in the market. Microscopes, refractometers and polarimeters are our specialty and we deal in all kinds of microscopes, refractometers and polarimeters from small scale to high-end units. We carry the latest models, and a wide range of microscopes, refractometers and polarimeters, which are available from us at reasonable prices.

Microscopes, Stereo Microscopes, Microscope Cameras and other products such as Refractometers, Brix Refractometers and polarimeters are available at online shop. You will find a variety including clinical microscopes, microscope cameras, VanGuard scopes and brix refractometers. Apart from these models digital microscope cameras are available for clinical and research laboratories.

National Microscope Exchange (NME) is a leader in the field of microscope, refractometer and polarimeter sales and service. We conduct business with all levels of the United States Government, doctors, hospitals, research centers, clinical laboratories, primary and secondary educational institutions, colleges and universities, medical schools, private industry, students, and hobbyists. We provide you with the best possible quotes and services. We guarantee complete satisfaction for your microscope, refractometer and polarimeter purchases and at the best value for your money.

Author Name: Kathy Brasch : Nationalmicroscope.com