The ISO Guide Star Catalogue: Fields Description.

Field 1: ISO Number.
A running number, increasing with right ascension (1 to 135387).

Field 2: # (Catalogue version: 1 or 2).
1 = Used between revolution 0 - 222. Based mainly on TIC.
2 = Used between revolution 223 and onwards. Based on the above
    catalogue and the data from the Hipparcos Output Catalogue 

Field 3: Hipparcos Input Catalogue (HIC) Number.
Reference number in the Hipparcos Input Catalogue 
(Turon et al. 1991b). Blank if the Star is not in HIC.

Field 4: GSC/TIC Number.
Number in the GSC and TIC catalogues (this is a region number
between 1 and 9537, and a running number, smaller than 32767,
within the region). TIC and GSC use the same numbering scheme.
TIC stars not present in the GSC have running number larger
than 10000.

Field 5: DM Number.
Number in the Durchmunsterung catalogues (declination zone;
running number in the zone; code for DM catalogue and component
number: 0 for BD ; 20 for Cordoba; 40 for Cape Photographic
Durchmusterung) from the SIMBAD database. 
Blank if no DM number is available.

Field 6: B Magnitude.
Field 7: Estimated error on B magnitude.
Field 8: V Magnitude.
Field 9: Estimated error on V magnitude.

Note: B and V magnitudes are given in the UBV Johnson system.
Field value is 99.99 (9.99 for error) when the magnitude
is not known.

Field 10: Spectral Class.
HD Spectral class from the INCA and SIMBAD databases. 
It is blank when the spectral class is not known.