Two-Micron Sky Survey, or IRc, or Infrared compact, or Caltech infrared catalog is the astronomical catalogue of the infrared sources published in the 1969 by Neugebauer

Gerald Neugebauer

Gerald 'Gerry' Neugebauer is an American astronomer known for his pioneering work in infrared astronomy.Neugebauer was born in Göttingen, Germany and is the son of Otto Neugebauer, an Austrian-American mathematician and historian of science, and Grete Bruck. After moving to the United States at...

 and Leighton.
Catalogue index consists of two numbers - declination

Declination

In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...

 rounded to multiplier of 10 degrees, with sign

Plus and minus signs

The plus and minus signs are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Their use has been extended to many other meanings, more or less analogous...

, and star ordinal number within declination

Declination

In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...

 band. Catalog contains about 5000 objects, most of them are M-type stars.

The IRc catalog data format is plain text, after uncompressing by unzip or gunzip it can be seen by any text viewers or by online ADC viewer.

Download locations

• Standard IRc catalog
• Update to IRc catalog: Classification of 831 two-micron sky survey sources south of +5 degrees