Plot
? |
Symb
? |
Source
* |
Average ? |
Thresholds ? |
N_
data |
QC1
parameter |
Data
downloads |
Remarks |
| method |
value |
unit |
method |
value |
| 1 |
• | QC1DB |
MEDIAN |
0.912 |
flux_ratio |
none | |
27 |
flat_spec_a |
this |
last_yr |
all
|
current flat / reference flat = a + b * (lam - lam0) |
| 2 |
• | QC1DB |
MEDIAN |
1.05 |
1/nm |
none | |
27 |
flat_spec_b |
this |
last_yr |
all
|
current flat / reference flat = a + b * (lam - lam0) |
| |
|
*Data sources: QC1DB: QC1 database; LOCAL: local data source
|
Plot 1
scores: not implemented
| | data source: | xshooter_flat
(QC1 database) |
| dataset: | flat_spec_a | • |
| median: | 0.912 | flux_ratio |
| thresholds: | none | |
| N_data plotted: | 27 |
| [click plot for closeup] |
Plot 2
scores: not implemented
| | data source: | xshooter_flat
(QC1 database) |
| dataset: | flat_spec_b | • |
| median: | 1.05 | 1/nm |
| thresholds: | none | |
| N_data plotted: | 27 |
| [click plot for closeup] |
This plot monitors XSHOOTER flat field spectra.
For this reason flat field spectra are generated and are
compared to a reference flat field spectrum.
We fit the flat field spectrum via the following linear formular:
current(lambda) = reference(lambda) * ( a + b * ( lambda - lambda_0 )
where lambda_0 is the center wavelength of the considered wavelength range,
parameter a is the relative overall flux of the spectrum, corresponding
to the lamp power and parameter
b is a first order chromatic deviation (the slope between the reference flat spectrum and
current flat spectrum). The reference spectrum is from 2015-10-24.
This plot shows both parameters a and b, of which paramter b is the important one.
On 2015-10-24, there is a=1 and b=0 by definition.
E.g. a = 1.22 means the current flux calibrated flat spectrum is 22%
brighter than the flux calibrated reference spectrum.
A negative b (e.g. b = -1e-4) means the spectral slope of the current
spectrum is less steep, hence blueer than the reference spectrum.
In the trending plot, increasing b means the spectrum becomes redder, decreasing b means the spectrum
gets more blue.
General information
Click on any of the plots to see a close-up version.
The latest date is indicated on top of the plot.
If configured,
- data points belonging to the latest date are specially marked
- statistical averages are indicated by a solid line, and thresholds by broken lines
- outliers are marked by a red asterisk. They are defined as data points outside the
threshold lines
- "aliens" (= data points outside the plot Y limits) are marked by a red arrow (↑ or ↓)
- you can download the data for each parameter set if the 'Data downloads' link shows up
|
mirror sites:
PL (internal
link) HQ
[?]
