This application is using to convert values between Rømer and Centigrade.

°C:

The Centigrade scale, also known as the Celsius scale, is a temperature scale used by the International System of Units (SI).

As an SI derived unit, it is used by all countries except the United States, the Bahamas, Belize, the Cayman Islands and Liberia.

It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale.

The degree Celsius (°C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty.

Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.

From 1743 to 1954, the Celsius scale was based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure.

Prior to 1743, the scale was also based on the boiling and melting points of water, but the values were reversed (i.e. the boiling point was at 0 degrees and the melting point was at 100 degrees).

The 1743 scale reversal was proposed by Jean-Pierre Christin.

By international agreement, since 1954 the unit degree Celsius and the Celsius scale are defined by absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW), a specially purified water.

This definition also precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature with symbol K.

Absolute zero, the lowest temperature possible, is defined as being exactly 0 K and −273.15 °C.

The temperature of the triple point of water is defined as exactly 273.16 K (0.01 °C). This means that a temperature difference of one degree Celsius and that of one kelvin are exactly the same.

°Rø:

The Rømer scale (Danish pronunciation: [ˈʁœːˀmɐ]; notated as °Rø), also known as Romer or Roemer, is a temperature scale named after the Danish astronomer Ole Christensen Rømer, who proposed it in 1701.

It is based on the freezing point of pure water being 7.5 degrees and the boiling point of water as 60 degrees.

Daniel Gabriel Fahrenheit, inventor of the Fahrenheit scale, learned of Rømer's work and visited him in 1708. Fahrenheit described how he borrowed the idea for his scale from this visit, but increased the number of divisions.

Newton published his scale in the same year as Rømer. Newton's system was calibrated between the freezing point of water (0 degrees) and human body temperature (12 degrees); it was a coarser scale, but unlike Rømer's it was not intended for everyday use, as Newton's interest was in determining the boiling points of metals, which are not readily accessible with Rømer's system based on liquid thermometers.

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