KI V2 Data Products
Spectrometer (.spec) File
Spectrometer files are ASCII text files that contain the narrow-band L-1 V2 data for KI. The following gives an example of a line from a KI summary file:
SPEC 01/01/2001/05:46:51 5.780970 HDC202240 5.965783 40.000000 0.837 500 0 KI_K1K2
4 2.400 175.8 0.645 0.482 1.200 2.300 195.8 0.569 0.420 1.200 2.200 189.1 0.507 0.369 1.200
2.100 122.7 0.488 0.343 1.200
The line consists of a number of space-delimited fields. The meanings of these fields are summarized in the table below. Each line corresponds to a block average of data (typically 5 to 25 seconds of fringe data, not necessarily contiguous). All entries, including time and delay line position, are mean values for the block. A # as the leading character indicates a comment.
|
field# |
content |
comments |
|---|---|---|
|
|
SPEC |
File identifier. Each line starts with SPEC to support the grep extraction mechanism from the intermediate data file produced by the L1 reduction code (Kvis). |
|
|
observation date |
UTC date of the observation (dd/mm/yyyy/hh:mm:ss) |
|
|
observation time |
Mean observation time (decimal UTC hours) |
|
|
source designation |
Source designation (ASCII string) |
|
|
FDL optical path |
Mean fast delay line optical path difference (m) |
|
|
LDL optical path |
Mean long delay line optical path difference (m) |
|
|
phase jitter |
RMS phase difference between consecutive fringe sample (radians) |
|
|
frame rate |
Fringe tracker rate (Hz) |
|
|
cal flag |
Internal calibration quality flag (*) |
|
|
baseline |
Baseline name |
|
|
number of SPEC channels |
Number of spectrometer channels |
Then, for each pixel ("channel") i (1..n), the following fields are given:
|
field# |
content |
comments |
|---|---|---|
|
12 + 5*(i - 1) |
wavelength |
Wavelength (microns) |
|
13 + 5*(i - 1) |
flux |
Spectrometer channel flux. DN units (approximately 5 photons/DN) |
|
14 + 5*(i-1) |
Incoherent V2 |
Spectrometer channel incoherent visibility squared (dimensionless) |
|
15 + 5*(i - 1) |
Coherent V2 |
Spectrometer channel coherent visibility squared (dimensionless) |
|
16 + 5*(i-1) |
ratio correction |
Spectrometer channel V2 ratio correction (dimensionless) |
The calibration flag has the following possible values:
- 0: OK
- 1: time difference between fringe data and background > CalTime
- 2: time difference between foreground and ratio data > CalTime
- 3: both 1 and 2 true
- 4: no ratio data exists within CalTime
- 5: both 1 and 4 true
where CalTime = 10 minutes.