Archive |
Spectrograph |
Data products
Description of the spectrum parameters
sn26
Gives the signal-to-noise ratio achieved at the center of order 26 [out of orders 0-38], corresponding to 5550 Å (near the center of the V band).
mode
Indicates whether the HE (high efficiency) or HR (high resolution) mode was used. See the spectrograph web page
for details on the fiber throughput and corresponding spectral resolution.
obstype
The type of observation is assigned during the archiving process to distinguish between various types of observations on the sky: SCI, for a regular science exposure, TST, for tests, like for example to focus the telescope, and CAL for calibration, for example exposures on the blue sky.
fiber_B
This parameter indicates how the second fiber in a given A,B pair was used.
Fiber_A contains the target spectrum. Possible values for fiber_B can be :
DARK (no light admitted), SKY (exposure to the sky background), WAVE (Thorium-Argon lamp) or
FP (Fabry-Pérot étalon).
For 90% of SOPHIE spectra the second fiber contains the spectrum of either the sky (40%)
or a wavelength calibration lamp (60%) depending on the scientific program.
exptime
Actual exposure time in seconds.
view_spec
Allows the user to view an auto-scaled plot of the one-dimensional
spectrum (s1d), rebinned to a constant wavelength step (0.01 Å
step), where the orders have been approximately corrected for the blaze
function and reconnected. There may still be present a residual blaze effect (5%) in both the HR and HE modes. If the spectrum is
less than a
year old, the data are not yet available to outside users. For more information on the 's1d' format, see the
data products page.
view_head
Allows the user to browse through the FITS header corresponding to this spectrum.
get_spec
Allows the user to download the 's1d' spectrum of fiber_A as a FITS file.
The spectrum of fiber_B (either the sky or the Thorium-Argon lamp) is
included as a FITS extension to the 's1d' file.
get_e2ds
Allows the user to download the extracted spectrum in order space (e2ds). This
file contains 39 lines of 4077 pixels corresponding to the actual spectral
sampling by the CCD. This file format can help users to explore
ways to compensate for the blaze undercorrection.
- Each 'e2ds' spectrum is associated with a 'wave' file, having
the same format, containing the wavelengths for all the pixels of the object
spectrum, and with a 'blaze' spectrum, derived from a tungsten lamp exposure,
which can be used to do an approximate correction for the blaze function.
These files are included as the first and second FITS extensions to the 'e2ds' file.
- For 90% of SOPHIE spectra the second fiber (B) contains the spectrum of either the sky (40%) or the Thorium-Argon calibration lamp (60%) depending on the scientific program. The spectrum of fiber_B and the necessary calibration files ('wave' and al
so 'blaze', but the latter should be disregarded) are included as the third, fourth and fifth FITS extensions to the 'e2ds' file.
customize
This page allows the user to customize the spectrum in different ways before viewing it and/or downloading it.
search_CCF
Show the different CCFs available for this observation,
then list the CCF parameters and plot the average CCF over the entire 60 km/s velocity interval for each CCF.
bjd
The barycentric julian date corresponding to the mid-point of the observation.
|