Description

Fischer Precision Aneroid Barometer

Accuracy: better than or equal ± 0.7 mb (± 0.02 inHg)
Graduation: 0.5 mb and 0.05 inHg
Dial: flat white finish; diameter 5.1″
Units on dial: mb and inches of mercury
Housing Diameter: 6.5″
Weight: 1.6 pounds
Measuring Range: 890 to 1050 mb = 26.30″ to 31.00″
For use at elevations below 2,600 ft
(A high elevation model for 2,600 to 6,500 ft is available on request.)

Precision aneroid barometers are used for measuring the absolute atmospheric pressure. Because of the excellent instrument properties and dependability an aneroid barometer is indispensable for meteorology, ocean navigation, industry, and research.

The self-stablized set of five aneroid capsules used in this precision instrument are made of a corrosion proof copper-beryllium-alloy. This alloy has been well established for measuring the atmospheric pressure for many years because of its remarkable elastic properties. The aneroid capsules are nearly free of age-hardening, hysteresis, and elastic after-effects.

The influence of temperature on the set of aneroid capsules and the transmission system is compensated by a bimetal arm over the whole measuring range and for temperatures between -30 to +40 °C (-22 to 104 °F). The motion of the aneroid capsule is transmitted to the axle of the pointer by driving a segment and wheel with an excellent fine finish gearing. All bearings also have an excellent fine finish. The Instruments have only a bare minimum of idle friction because of the advantageous shape of the levers and bearings.

To barometer professionals, this is one of the highest quality aneroid barometers in the world. It has been tested at sea for over 70 years, and used by Navies and Weather Services around the world, including the NWS Voluntary Observing Ship program. The double needle design removes parallax error in reading.

The new dials showing both millibars (mb) and inches of mercury have been custom made for American and British users on land and sea. The mb (same as hectoPascals) dial is the international standard for maritime applications.

Purchase includes a free printed copy of The Barometer Handbook by David Burch

Why Buy a Barometer

Even in these modern times of satellite phones and internet, the atmospheric pressure measured with your own barometer remains the most important indication of weather changes at your location. To evaluate present weather or to forecast coming weather, we need accurate barometric pressure. Most common barometers on the market are not accurate enough to serve this purpose. They are more decorative than functional.

Barometer vs. barograph? 
A barometer displays the present pressure and the change of pressure since it was last set using a marker hand on the dial. A barograph records the history of the pressure on a paper chart, wrapped around a clock-driven drum. Underway on a fully crewed vessel, the logbook serves as a detailed record of pressure changes. On overnight anchorages, a printed barograph trace is a convenient way to learn how the pressure changed during the night when there was no watch to record it. Keep in mind, however, that with a good aneroid device you still have the set hand to learn how the pressure changed overnight. So if this is a concern, set the hand in the evening to the pressure then, and read the change in the morning.

Mechanical vs. electronic instruments?
Mechanical (aneroid) barometers have been used on land and sea continuously since the mid 1800s. By the 1960s, precision aneroid barometers were fully developed and available from selected dealers. Navies and weather-service vessels worldwide rely on these aneroid instruments daily. The Fischer precision aneroids are the last of original technology that revolutionized the aneroid technology in the 1950s. They are still produced today as they were 60 years ago, and they remain unmatched in dependability.

Electronic barometers are small pressure sensors, read and controlled by microprocessors with a digital and sometimes graphic display. They have been used in science laboratories for many years. Affordable models intended for public use became popular a few years ago. As with aneroid barometers, there is a wide range of quality in electronic barometers. All barometers should be periodically compared with known pressures from official weather services.

To learn how barometric pressure can be used in weather analysis see The Barometer Handbook.