ORCHID System Engineering J. Kent Wallace 14 Oct 2010

The Plan 1.Summarize status from last meeting. 2.Review status of system priorities. 3.Review plans for next few weeks.

System Priorities as of 14 Oct: STATUS 1.Quantify performance of coronagraph tip/tilt system. DONE 2.Understand system throughput DONE 3.Model impact of ADC on contrast STARTED 4.Examine sensitivity of Coronagraph to low-order aberrations STARTED 5.Quantify the current optical alignment and create alignment plan. STARTED 1.Each sub-system individually 2.Sub-system co-alignment – Corongraph/CAL: DONE 6.Model phase-induced amplitude errors in the pupil STARTED 7.Quantify impact of anti-aliasing filter on CAL NOT DONE

Throughput Created photometry spreadsheet that quantifies stellar photons and system throughput based upon surface-by-surface reflectivity. Processed some on sky data as measured by the CAL system. Conclusion: Up to CAL, there is reasonable agreement between expected and measured photon fluxes.

Stellar Flux

AO System Throughput

CAL Science Throughput

Total Frame DN vs Frame No. Average H-band Flux = 5 * 609,300 DN per sample * 6.3 e- per DN / (0.6 e- per photon) Average H-band Flux = ^7 photons/sec Average DN = 609,300 per 5 Hz Sample

Theoretical CAL Flux Theoretical CAL Flux = Stellar Flux * AO Throughput * CAL Throughput Theoretical CAL Flux = ^9 photons per sec* 0.785* Theoretical CAL Flux = ^7 photons per sec Experimental Average H-band Flux = ^7 photons/sec Experimental = 0.5 Theoretical

Tip/Tilt Telecon Action Items ACTION ITEMS: Ben is to provide raw data on the quad cells reasonably soon. DONE P3K to verify that its software supports P1640 Coronagraph PZT tip/tilt offloads to the P3K tip/tilt system. This capability will be needed by P1640 on sky. DONE Ben to provide software upgrades to allow recording of quad cell tip/tilt data. DONE Rick, Kent, Gautam and Mike to document co-alignment of the FPM/Quad Cell/Pinhole DONE Kent and Gautam to clarify, operationally, who is the person to determine that the system is ready to observe. DONE

Initial Starting Point

Step 3: Center Quad Cell on Star Step 3 Details Signal: Error Signal on Quad Cell Actuator: Quad Cell Position Algorithm: Zero out Quad Cell x and y tilt Responsibility: AMNH

Next Steps: Status Integrate sub-system error budgets STATUS: NOT DONE Come to consensus on a common performance metric (contrast curve definition) STATUS: STARTED Initiate detailed system performance modeling STATUS: STARTED Dimtri is building up the simulation, so we gathering information to include in this Coordinate a plan of attack for regularly addressing highest priority tasks.

Plan of Attack ItemTimePeopleTasksGoal Review/Combine Error Budgets Wed Oct 6 PAST DUE Rich, Mike, Kent, … Spreadsheets for P3K and CAL. Preliminary combined performance estimate Throughput/ Emissivity Thurs Oct 7Ben, Kent, Mike, GV, … Measure P1640 bench optics, analyse CAL Data Validate Budget, Identify optics of concern ADC Performance Analysis Thurs Oct 7 PAST DUE Ben, Dimitri, Kent, Mike, Rich, Model impact of ADC on system. Measure ADC Throughput Quantify impact of ADC on Contrast