## Index

The index containing the title of all the observations in an input file is read when the file is opened. Starting with the use of CLASSIC , and to allow files with a larger number of observations or records, the version 2 of files uses 8-bytes integers wherever needed. In addition, with version 2, observations do not have to start at the beginning of a record, so no space is left blank in the file. Table 1 describes the content of an observation title.

Table 1: Version 2 of observation title.
Word | Starting word | Length | type | unit | comment
bloc | 1 | 2 | INTEGER*8 | [records] | record number of entry start
word | 3 | 1 | INTEGER*4 | [4-bytes] | offset in words in record
ver | 4 | 1 | INTEGER*4 |  | version of the observation
num | 5 | 2 | INTEGER*8 |  | observation number
sourc | 7 | 3 | INTEGER*4(3) |  | source name
line | 10 | 3 | INTEGER*4(3) |  | tuning name
teles | 13 | 3 | INTEGER*4(3) |  | interferometer configuration
dobs | 16 | 1 | INTEGER*4 | [days] | classic date of observation
dred | 17 | 1 | INTEGER*4 | [days] | classic date of reduction
off1 | 18 | 1 | REAL*4 | [radian] | lambda offset
off2 | 19 | 1 | REAL*4 | [radian] | beta offset
typec | 20 | 1 | INTEGER*4 |  | type of coordinates
kind | 21 | 1 | INTEGER*4 |  | data kind
qual | 22 | 1 | INTEGER*4 |  | data quality
scan | 23 | 1 | INTEGER*4 |  | scan number
proc | 24 | 1 | INTEGER*4 |  | procedure type
itype | 25 | 1 | INTEGER*4 |  | observation type
houra | 26 | 1 | REAL*4 | [radian] | jour angle
project | 27 | 2 | INTEGER*4(2) |  | project name
bpc | 29 | 1 | INTEGER*4 |  | baseline bandpass cal status
ic | 30 | 1 | INTEGER*4 |  | instrumental cal status
recei | 31 | 1 | INTEGER*4 |  | receiver band number
ut | 32 | 1 | REAL*4 | [s] | UT time