LESIA - Observatoire de Paris

GriF commands/files

2008-11-12T15:04:50Z

– "fp" command : to execute a scan

fp -bcv BCVi BCVf -nstep n (n is the number of steps of the scan)

fp -bcv BCVi BCVf -step step (step is the step width of the scan)

fp -wave Wi Wf -nstep n

fp -wave Wi Wf -step step

fp -wave Wc -1 -nstep n (to make a n-step scan around the value Wc, with a step size set by setgrsampling)

fp -lamb Wc (to make an image at the Wc wavelength)

– "setcalib" command : to adjust the wavelength calibration

setcalib lambda BCV

– "setparal" command : to adjust the parallelism of the FP

setparal BCVX BCVY

– "setgrsampling" command : to adjust the default step size of a scan

setgrsampling stepsize

– "grifin" command : to set the approriate focus filter values when the FP is in the beam (cannot be typed in Xterm with a bash shell)

grifin

– "grifout" command : to set the appropriate focus filter values when the FP is out of the beam (cannot be typed in Xterm with a bash shell)

grifout

– "grifsetup" command : to set the desired setup of the Gumball lamps

grifsetup cont (to light on all the continuum lamps) grifsetup argon (to light on all the argon lamps) grifsetup neon (to light on all the neon lamps, if any) grifsetup krypton (to light on all krypton lamps, if any) grifsetup clean (to light off all lamps) grifsetup object (to be execute before making a scan on an object)

– "/h/grif/.,grifh.par" file : in this file are stored the values selected by the aforementioned commands (setcalib, setparal, setgrsampling, grifin/out, grifsetup)

– "griffp" command : to send BCV to the CS 100 or reset the iotechs

griffp -z BCVZ (set BCVZ on the Z channel) griffp –xy BCVX BCVY (set BCVX on the X channel and BCVY on the Y channel) griffp -i (reset the iotechs) griffp -r (reset the iotechs)

Flat field

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– Choose the same filter as used for the scientific scan on the object
– From the AOB GUI, put three neutral density filters for the APDs of the AOB
– On the GriF Xterm, type "grifsetup clean" to light off all Gumball lamps
– On the GriF Xterm, type "grifsetup cont" to light on the continuum lamps of the Gumball
– On the GriF Xterm, type the same scan instruction as done for the scientific scan on the object (eg "fp -wave 2.1218 2.1238 -nstep 5")
– If you are then going to make a scan on a scientific object, don't forget to type "grifsetup clean" and "grifsetup object"

Checking the parallelism of the FP

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– First, in the GriF Xterm, type "more .,grifh.par" to check that the the BCVX and BCVY values are the default ones

– from the first wavelength calibration scan (or any following scan of the 2.06163 µm line), build a phase map by typing the Phase Xterm "remsh noeau grifpar fichier.log", where fichier.log is the logfilename of the corresponding scan (eg 701324.log). This will create a phase.fits file in /h/grif.

– from any appropriate software (idl, saoimage, ...), check that on this phase map, the central pattern is centered on the detector as shown on the following images

On the obtained phase map, the range of values is hardly scattered ( 1-1.5). If this is not the case :
– check the CS100 setup values
– modify by a small amount the BCVX and/or BCVY values by making a new scan of the 2.06163 µm argon line. By looking at the direction of displacement of the fringes during the scan, one can determine how to change the BCVX and/or BCVY values (see the following scheme)

First wavelength calibration

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– From the AOB GUI, go to the "Set up configuration" of the AOB

– From the DetI GUI, type "etime 1"

– Choose Kprime filter

– From the DetI GUI, type "snap" to check that one can see the artificial star

– From the AOB GUI, go to the "Observer configuration" of the AOB

– Choose Brackett gamma filter

– From the AOB GUI, put three neutral density filters for the APDs of the AOB

– On the GriF Xterm, type "grifsetup clean" to light off all Gumball lamps

– On the GriF Xterm, type "grifsetup cont" to light on the continuum lamps of the Gumball

– On the GriF Xterm, type "griffp –z -700" and "griffp –z 300" to check that the FP is scanning (fringes must move, if not reset the iotechs with the griffp command)

– Choose Kprime filter

– From the DetI GUI, type "etime 15" (if there are 2 argon lamps in the Gumball) or "etime 10" (if there are 3)

– On the GriF Xterm, type "grifsetup clean" to light off all Gumball lamps

– On the GriF Xterm, type "grifsetup argon" to light on the argon lamps of the Gumball

– On the GriF Xterm, type "grifscanfp –bcv –890 –755 –nstep 10" to make a 13-step scan of the He I line at 2.06163 microns

– When the scan is finished, on the IDL Xterm, in IDL, execute the command "calc_const_fp" to get the observed BCV profile. The program computes "BCV_cal", the BCV corresponding to 2.06163 microns

– On the GriF Xterm, type "setcalib 2.06163 BCV_cal", where BCV_cal is the value given by the IDL program (choose the one with the lowest chi2 value)

GriF Fabry-Perot set-up procedures

2008-11-12T15:03:59Z

To be done by CFHT staff

Before installing the FP in the GriF spacer, the following procedures must be followed for the set-up of the FP :
– remove the Gumball densities
– check that the proper resistance has been connected in the CS 100
– adjust the potentiometers of the CS 100 front panel to the appropriate values
– close the loop on the CS 1000
– adjust by eye the parallelism of the FP

The FP can now be placed in the GriF spacer.

Then, the following procedures must be followed :
– adjust the default values of the FP parallelism
– focus the different KIR filters and GriF grism(s ?)

To be done then by the observer and/or the support astronomer (as an introduction to GriF)

Preliminary operations to be followed : from the GriF Neptune session,
– open an first Xterm window (called "GriF Xterm" in the following), type “grifin” and then “bash”
– open a second Xterm (called "IDL Xterm" in the following), on which you log on kou (with the observer login/passwd), copy /h/grif/idl/idl_setup on the home directory of the observer account, execute "source idl_setup", change to directory "/h/grif", and run idl
– open a third Xterm (called "Phase Xterm" in the following) and type “bash”

Then, the observer should follow the following procedures :
– first wavelength calibration
– check the parallelism of the FP

To be done then by the observer

The FP is now ready for astronomical observations. These are made of the following operations :
– wavelength calibration
– type in the GriF Xterm " grifsetup clean" and "grifsetup object" before doing the scan of the object (astronomical object, PSF, calibration star)
– flat field (white light cube)

In the following page, you will find the different commands/files used with GriF

Default BCV values on the X and Y channels for FP parallelism

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BCV= -206

BCV= 246

In the GriF Xterm, type : “setparal -206 246” to set the appropriate values

CS 100 values for the front-panel potentiometers

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	Coarse parallelism	Fine parallelism	Balance	Loop gain	Time constant
X	0	1-20	8-15	32	25
Y	0	1-6	4-1	32	25
Z	0	2-25	4-40	32	25

GriF CS100

2008-11-12T15:02:04Z

The Fabry-Perot (FP) controller used for GriF is the MOS/FP Queensgate CS100, bought at the beginning of the 80's. This controller was a special order that had, built in, a smaller digital scanning range (typically 0.5 microns of displacement for the 4096 binary values range) than other controllers. When observing in 1996, B. E. Woodgate pointed out that he could not scan the same range as with his FP controller. Following the advice of P. Pietraszwski (Queensgate), CFH has implemented a small modification of the CS100 allowing a standard (and the larger) range of scanning. It consist in changing the resistor R17 on the offset controller module from its original (reduced) value (195k) to 50k (see figures below).


Fig. 1 : Module positions. Offset controller module is the second one from the left


Fig. 2 : Offset controller module. R17 is the lower encircled resistor

In practice, the offset controler board has been modified to have the two resistors (195k and 50k) always fixed on it. One is fixed on a non-connected location, the other on a connected location. Then, to change the scanning range, one has simply to exchange the resistors on their plugging locations (see photos below). For GriF, the "high range" 50k resistor must be connected.

GriF

2008-11-12T15:01:53Z

Présentation de GriF

GriF est un instrument permettant de combiner à la fois les images à haute résolution angulaire que permet l'optique adaptative et la résolution spectrale qui est indispensable pour obtenir des diagnostics physiques tels que vitesse, température, densité, excitation du milieu interstellaire, ages des étoiles, etc. On appelle spectrographe 3D (3 dimensions) un tel instrument qui permet d'ajouter aux deux dimensions spatiales de l'image la dimension des longueurs d'onde.

GriF a été développé au LESIA en collaboration avec le LAOG (Observatoire de Grenoble), l'Université Laval (Québec) et le Canada-France Hawaï Telescope (CFHT). La réalisation mécanique a été faite au pôle instrumental de l'Observatoire de Paris et à l'Université Laval.

GriF est en fait un mode d'observation complémentaire de la caméra infrarouge KIR, le système imageur de l'optique adaptative PUEO du télescope CFHT à Hawaii.

Principe et implémentation de GriF

Le principe de GriF est illustré sur le schéma de la figure ci-dessus : un Fabry-Pérot (FP) devant la caméra permet d'isoler plusieurs longueurs d'onde précises (les ordres du FP). Les images correspondant à ces différentes longueurs d'onde se superposeraient normalement sur le détecteur, mais on introduit auparavant dans le faisceau un système disperseur qui sépare les images monochromatiques sous forme d'images rectangulaires allongées juxtaposées. On dispose ainsi simultanément d'une série d'images du même objet, à différentes longueurs d'onde, tout en conservant l'avantage de la très haute résolution angulaire de l'optique adaptative.

L'ajout de ce mode d'observation est rendu possible par l'insertion dans le cryostat de la caméra KIR
– d'une roue motorisée portant des diaphragmes rectangulaires (voir photo),
– d'un "grism" (prisme sur lequel est gravé un réseau) sur la roue porte-filtre de KIR. On installe enfin l'étalon Fabry-Pérot devant la fenêtre d'entrée de la caméra KIR.

Premiers résultats

L'image dans le coin inférieur droit de la figure ci-dessus correspond à l'un des résultats obtenus lors du premier essai de GriF en décembre 2000 : il s'agit d'une région de la nébuleuse d'Orion où des éjectats d'hydrogène très rapides (probablement issus d'une étoile en formation) - déja observés auparavant - sont détectés ici dans une raie de la molécule d'hydrogène à 2.16 µm. Le codage en couleur correspond aux différentes vitesses mesurées avec GriF : le bleu indiquant une vitesse dirigée vers l'observateur. Ce résultat a été obtenu en collaboration avec une équipe du LERMA de l'Observatoire de Paris.

Personnels impliqués
Yann Clénet	Responsable du projet	LESIA
Robin Arsenault	Spécialiste Fabry-Pérot	ESO
Jean-Luc Beuzit	Scientifique	LAOG
Claude Collin	Assemblage-Intégration-Tests	LESIA
Claude Delage	Conception mécanique	LESIA
Thierry Forveille	Scientifique	CFHT
Gilles Joncas	Scientifique	Université Laval
Pierre Gigan	Assemblage-Intégration-Tests	LESIA
Bernt Grundseth	Electronique Fabry-Pérot	CFHT
Olivier Lai	Scientifique	CFHT
Etienne Le Cöarer	Spécialiste Fabry-Pérot	LAOG
Claude Marlot	Conception mécanique	LESIA
Patric Rabou	Conception optique	LAOG
Daniel Rouan	Scientifique	LESIA
Bernard Talureau	Assemblage-Intégration-Tests	LESIA
Jim Thomas	Informatique d'expérience	CFHT
Philippe Vallée	Réalisation mécanique	Université Laval