LBC BlueObserving

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LBC-Blue pre-commissioning : 

LBC-Blue pre-commissioning LBC-Blue E Giallongo (PI) Rome: diPaola, Pedichini, Speziali, Testa, Gallozzi Arcetri/Padova/Bologna: Ragazzoni (co-PI), Barufollo, Diolaiti Trieste: Smareglia, Gasparo field of view, filters taking data: preparing andamp; executing the observations Two pre-commissioning runs this year: Summer (May – mid-July) Fall (mid-Sept to present) leading up to LBC-Blue commissioning late October

Opto-mechanical Design : 

Opto-mechanical Design

LBC-Blue: focal plane: 

LBC-Blue: focal plane 4 2048 x 4608 pix ‘science’ chips 0.23'/pxl (7.85’ x 17.7’ per chip) separated by 80 pxl (18') gaps ~ 27’ x 27’ field of view 2 512 x 2048 pix ‘technical’ chips first 256 lines masked to be used without shutter (~frame transfer CCDs) fast readout: 1.2s for the 256x2048 area 1’ x 7.85’ field of view for guiding andamp; active optics all behind shutter andamp; filter from 'LBC Blue Channel: The CCD Camera' (Giallongo (PI), Speziali, diPaola, Pedichini , Ragazzoni (co-PI)andamp; LBC team)

Wavelength coverage: 

Wavelength coverage Filters intended (8/channel at one time) LBC-Blue: Bessel U,B,V Sloan g’, r’ (u’ to be added) LBC-Red: Bessel V, R, mod-I Sloan r’,z’ (i’ to be added) NB 910nm/30nm fwhm (under consideration) Sensitivities ETC gives 5s-1hr for 0.9' seeing, 1.8' SW aperture, no moon, airmass = 1.3: B~27.1, U~25.4, V~26.9 First light image at B consistent with estimate from ETC. Estimates only! to be measured during commissioning…

Preparing Observing Blocks: 

Preparing Observing Blocks OB tool runs on Linux andamp; Windows (Gallozzi) set pointing, position angle configure Blue andamp; Red channel: dither pattern, exposure time, Nexp Writes out xml file

Executing Observing Blocks: 

Executing Observing Blocks LBC Control SW: Runs from firefox browser Uploads OB Executes observation Interfaces with TCS: slews, obtains rotator trajectory, dithers Guiding for exposures longer than a given threshold (~30sec) Technical chip exposures 2,4,8,…sec taken Automatically searched for stars; when sufficient stars found, starts guiding

Focus & Collimation: 

Focus andamp; Collimation Slew to target Execute OB to move M1 down by 0.8mm (60pxl pupil) Obtain 15-20s image using a ~1000 line window of chip 2 Analyze with IDL algorithm (Barufollo andamp; Ragazzoni): Automatically finds bright isolated pupils computes Zernike coefficients sends the results to the TCS/PSF which adjusts mirror position andamp; forces 2-3 iterations to achieve focus andamp; collimation Frequency of focus/collimation? TBD, depends on accuracy of collimation lookup table

Summer (May to mid-July) pre-commissioning : 

Summer (May to mid-July) pre-commissioning CCD Controllers (Pedichini, Skytech) Returned from Rome/Skytech Source of pickup noise tracked down and eliminated Decreased image transfer time (diPaola andamp; Smareglia) 105s total: 26 s readout (41 s readout andamp; demultiplexing) transfer from LBC CMU to archive and from LBC archive to user machine Development of single extra-focal image analysis algorithm (Barufollo andamp; Ragazzoni) MAT (4' rms) and LBC (7.6' rms) pointing models First collimation lookup table made Mirror position (x,y,z,rx,ry) vs elevation for about a dozen datapoints. Outstanding Issues in mid-July: rotator cable chain buckling Focal plane tilt (100 microns) which had existed since fall 2005.

Fall (Sept – late Oct) pre-commissioning : 

Fall (Sept – late Oct) pre-commissioning New rotator cable chain installed Fixed focal plane tilt Shimmed rotator flange by 0.38mm Guiding works Tasks for the next two weekends: Refinement of collimation lookup table Refinement of pointing models (MAT and LBC) Refinement of active optics code (Oct 19-22) LBC-Blue Commissioning to begin October 23

Quantum Efficiencies: 

Quantum Efficiencies from Pedichini F., Speziali, R., Diolaiti, E., Ragazzoni, R. 2002, 'The Large Binocular Camera of LBT: The focal plane detectors', http://lbc.mporzio.astro.it/Documentation/The_Detectors.pdf (in later document, one blue chip differs; QE for this one 1-8% lower but similar shape)