NARVAL
example of spectra and frames collected during first light


Portions of stellar spectra as recorded by NARVAL during first light, around 550 nm. From bottom to top, spectrum of the Sun (reflected by the moon), of the K1/G5 RS CVn close binary system HR 1099 (in red) and of the F1p chemically peculiar star 53 Cam (in green). The spectra of HR 1099 and 53 Cam are shifted upwards by 0.3 and 0.6 respectively for graphics purposes.
Raw NARVAL image of the spectrum of the Sun (as reflected by the moon), with red and blue orders appearing respectively on the left and right sides of the frame. Only part of the spectrum is shown here (the full CCD being about twice as high). This image belongs to the sequence of four exposures collected to derive the solar spectrum shown above. Click on the image to zoom in.

Examples of NARVAL spectra and frames

To get a feeling of what NARVAL spectra look like, you can download test spectra collected during first light (2006 Nov 13):
one spectrum of the Sun after reflection by the moon and the corresponding log file of the reduction process
one spectrum of the K1/G5 RS CVn close binary system HR 1099 and the corresponding log file of the reduction process
one spectrum of the F1p chemically peculiar star 53 Cam and the corresponding log file of the reduction process


All spectra were taken in circular polarisation mode and are in the standard ESPaDOnS/NARVAL output format, ie a 6 column ascii file listing sequentially (i) wavelength (in nm), (ii) normalised flux I/Ic where Ic notes the continuum flux, (iii) circular polarisation V, (iv) and (v) check null polarisation spectra and (vi) corresponding error bar. The log file includes all relevant information about the corresponding exposures (such as UT and JD of exposure, exposure time, stellar coordinates, airmass, signal to noise ratio, etc...).

One of the corresponding raw frames is shown below. Most orders show up on the image, whose full height is trimmed by a factor of 2. The double structure of the orders is conspicuous, and corresponds to both orthogonal polarisation states recorded next to one another. Spectral lines (of the Sun in this particular example) are clearly visible in all orders.



© Jean-François Donati, last update Feb 06 2007.