A simple photometer

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

Descriptor values:

NFILTCAR = 2

NDETS = 1

FILTSTAT = DOME

FILTCAT = ' ' (blank string)

CONDITION = AVERAGE

Passband sub-table

NBAND	BAND	FILTCODE_1	FILTCODE_2	NDVALUE	REDLEAK	RLTYPE	MAKER
---	--	-----	-----	----	----	----	---
1	u	10	0	1.000	MEASURED	CEMENTED	SCHOTT
2	v	20	0	1.000	BLOCKED
3	b	30	0	1.000	BLOCKED
4	y	40	0	1.000	BLOCKED
5	uND	11	0	9.897	MEASURED	CEMENTED	SCHOTT
6	vND	21	0	9.763	BLOCKED
7	bND	31	0	9.674	BLOCKED
8	yND	41	0	9.695	BLOCKED
9	DARK	any	1

Detector sub-table

NDET	DET	SNUMBER	MODE	DEADTYPE	DEADTIME	DEADTIMEERROR	COOLING	DETTEMP
--	--	----	--	-----	----	-------	-----	----
1	PMT	QBIALKAI	PC	EXTENDING	6.74E-8	4.2E-9	REGULATED	273.