This is a description of the current (2019 and earlier) GCS configuration. Please note there is a "newGCS" branch, which aims to streamline GCS configuration, remove OAC handling to a new OAC subsystem, and more - this configuration will not be relevant once newGCS is deployed.


Located in /lbt/tcs/current/gcs/etc. The most important are entries specifying directories - PUB_CONF_DIR_GCS and CONF_DIR_GCS[LR]. The usuall shall be:

%CODE{lang="inf"}% PUB_CONF_DIR_GCS string /home/telescope/TCS/Configuration/GCS/ CONF_DIR_GCS string ./gcs/configuration/GCS/ CONF_DIR_GCSL string ./gcs/configuration/GCS/ CONF_DIR_GCSR string ./gcs/configuration/GCS/ %ENDCODE%

Those are then used for further GCS configuration.

CONF_DIR_GCS string (./gcs/configuration/GCS/)

./ points to /lbt/tcs/current, so the full path on mountain is /lbt/tcs/current/gcs/configuration/GCS/. The important files there:


Links focal stations/instruments with instrument config (in PUB_CONF_DIR_GCS) and instrument config with AGWs. Please note that only the last line for the instrument - config is used - e.g. from the multiple LUCI_L lines, only the last will be used.

%CODE{lang="inf"}% # Luci L_LUCIFER_BENTGREGORIANFRONT LUCI_L.cfg string LUCI_L.cfg AGW3.cfg string


Will link left LUCI bent gregorian front and left RETROREF bent gregorian argos focus/instrument combination to LUCI_L.cfg. For both, AGW1.cfg will be used - AGW3 will not be used.


Configures AGW - contains AzCam IP and ports, and rotator among others. Linked from Instrument2AGW.cfg.

AGWx_WFScam.ini and AGWx_guidecam.ini

AzCam commands send to the camera on AGW initialization.

PUB_CONF_DIR_GCS (/home/telescope/TCS/Configuration/GCS/)

WFS and guide cam configuration. List position of a pinhole, rotation of AzCam in relation to KFP etc.

Changing AGW/instrument configuration

When changing AGWx for AGWy for an instrument, the following shall be changed (IT7252):

  • Instrument2AGW.cfg link proper instrument to AGWy instead of AGWx; keep in mind only last line is relevant

  • AGWy.cfg check instrument rotator assignement:
%CODE{"inf"}% WFS_rotatorAngle mcs.rotatorSide[1].rotators[X].actualPositionASec string # name of DD variable containing the rotator position for this AGw %ENDCODE% Where X is 2 for fbg (front bent Gregorian), 5 is for dgr (direct Gregorian).

  • Check PCS [LEFT|RIGHT]ZEROPOINT just in case the bolt circles are clocked differently on AGWy versus AGWx

  • The following variables in INSTRUMENT_SIDE.cfg (LUCI_L.cfg,..) for GCS need to be updated in the new version of LUCI_L.cfg. These instructions assume you are editing a new copy of LUCI_L.cfg. Similar changes are needed in the lbto version of ~/idl/wfsc/agw/ in the LFBG section. Update the Header Comment that identifies the AGW. These MUST CHANGE as they are primarily properties of AGW geometry, and they can also change if the AGW has been worked on.
    • newHKEnabled (1 - new TCP/IP HK board, 0 - old HK board, OAC internal)
    • guidecam_hotspot_[xy] (get values from AGWy or new lab measurements)
    • WFScam_hotspot_[xy] Center of the on-axis pupil on the wfs image (pixels); IDL parameters are pupil_x_on-axis (and y). Use gcs_wfsc_display and GCSGUI to check.
    • WFScam_hotspot_sext_[xy] Defines lenslet array position on the wfs CCD (get values from AGWy)
    • WFS_lenslet_rotation (lenslet grid rotation with respect to CCD columns)
    • WFS_lenslet_edge_[xy] (get values from intstrument for AGWy). Note: IDL parameters lenslet_x_center (and y) are the pixel coords of the lower left corner of the full lenslet array. Add 13.3*8.5 to lenslet_x_center (and y) to get the GCS parameter. Use IDL wfsc_lenslet_display to check - grid should match the illuminated lenslets.
    • WFS_flipX (flip Zernikes along X axis (default to false) (for IT 7282 / 7316 20180628))

  • Things that do NOT need to change, but were different between AGW1/AGW3.
    • WFS_fluxSigmaFactor See also IT 6447 and email to dlmiller We'll keep the values the same for the individual AGws, but this could use some regularization later if we can understand which values are best.
    • WFS_rotAngleOffs LUCI_L = 6.0, PEPSIPOL_L = 34.0 We think this is mostly focal station geometry, so does not need to change.
    • pointingCorr_flip_[xy] (flip_x changes sign for guide CCD readout parity / alternate amplifier, AGW3 uses -1; flip_y always +1)
    • guidingCorr_flip_[xy] (flip_x changes sign for guide CCD readout parity / alternate amplifier, AGW3 uses -1; flip_y always +1)

  • These don't change as they are focal station dependent.
    • WFS_pupil_shift_[xy] (changes sign for M3 reflection, and AGW base coordinate system)
    • rotAngleDir (changes sign for M3 reflection)
    • WFS_probeRotationFactor 1.0
    • SFP_rotation (rotation of AGw coordinate system in relation to SFP. LUCI = 179.7 (There is an interaction with LEFTZEROPOINT / RIGHTZEROPOINT.))

  • These don't change as they were specific for PEPSI observing.
    • FSCALE (4.0 to 1.0) FWHM scaling for selecting guide star
    • MSCALE (1.0) Magnitude scaling for selecting guide star
    • RSCALE (60.0) Radius scaling for selecting guide star
    • CSCALE (1.0) Star class scaling for selecting guide star
Topic revision: r4 - 07 Mar 2022, JohnHill
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