First, consider a very simple 1-channel UBV photometer.
Let us assume a rather minimal instrument: no cooling or temperature
regulation, and simple DC photometry.
This resembles the instrument with which the UBV system was first set up.
Here is the table:
Table:
Instrument table file for a simple photometer
Descriptor values:
NFILTCAR = 1
NDETS = 1
FILTSTAT = DOME
FILTCAT = ' ' (blank string)
CONDITION = AVERAGE
Passband sub-table
NBAND
BAND
FILTCODE_1
REDLEAK
RLTYPE
MAKER
---
--
-----
----
---
----
1
U
3
MEASURED
LOOSE
CORNING
2
B
1
IGNORED
3
V
2
ABSENT
4
URL
4
ABSENT
Detector sub-table
NDET
DET
SNUMBER
MODE
COOLING
--
--
----
--
----
1
PMT
S-4
DC
NONE
As there is only one detector, we need not include the NDETUSED column.
Table:
Instrument table file for a typical modern photometer