How do you measure snowfall?

How do you measure snowfall?

| February 24, 2014 | Reply

Measuring snowfall is a tricky business. Snow blows around, makes drifts, compresses, and melts. To measure snowfall we use snowboards (not the kind you ski on!). These are flat boards located in the gated area next to the Observatory building. And, yes, we do measure snowfall with a ruler. The measuring sticks we use are […]

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Why doesn’t the sunshine recorder card burn up?

Why doesn’t the sunshine recorder card burn up?

| February 24, 2014 | Reply

As anyone who has tried to start a campfire knows, starting a fire is harder than it looks. The focus of sunlight is so precise; it burns away any flammable material as the earth spins and the dot moves thus preventing the card from burning up.

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What happens to the recording card in the sunshine recorder if it rains?

What happens to the recording card in the sunshine recorder if it rains?

| February 24, 2014 | Reply

Essentially, nothing. The paper has a coating to prevent it from getting soggy. The recording card can remain in the sunshine recorder for several days without damage. What is more important is to change the card at proper times when the sun is shining to prevent over burn of yesterday’s data with todays.

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What is that “crystal ball” on the table in the History Room and on the roof of the tower?

What is that “crystal ball” on the table in the History Room and on the roof of the tower?

| February 24, 2014 | Reply

The “crystal ball” is not used to predict the future (although we wish it could do so). The crystal ball is actually a Campbell-Stokes sunshine recorder. This device was in use on the roof of the building for over 100 years. The sunshine recorder is essentially a magnifying glass that burns a track in a […]

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What is that “spikey thing” on the roof?

What is that “spikey thing” on the roof?

| February 24, 2014 | Reply

This equipment belongs to the National Weather Service. It measures wind speed and direction ultrasonically. The spikes keep the birds off the equipment.

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Why do you need so many anemometers?

Why do you need so many anemometers?

| February 21, 2014 | Reply

One of the key aspects of Blue Hill Observatory is that we maintain homogeneous data. By having multiple instruments we are able to ensure data is never lost and that all the instruments are working correctly.  Some of the instruments are official, some are back-up, and others are used for educational purposes. We sometimes receive […]

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How often is the mercury barometer calibrated?

How often is the mercury barometer calibrated?

| February 21, 2014 | Reply

The mercury barometer contains no electronics or moving parts. Its need for calibration is minimal. We are constantly checking the readings from the mercury barometer against other instrumentation to make certain that the device continues to read accurately.

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