---+++ TMAS Visible Light AO Instrument Observing Candidate Observing Modes ---++++ Note all numbers on this page has yet to be verified! ---+++++ Input focal plane * F/15.4 (or so?) implies 2.637 "/mm * 25.4 mm window = 67 arc sec diameter = big enough for any Channel described below * 12.7 mm window = 33.5 arc sec diameter = slightly too small for Channel 1 ---+++++ TMAS cameras * Leading option * 2 ea. Andor 5 MPix (2560 x 2160) NEO sCMOS cameras from Gregg Hallinan * 6.5 micron pixels; 16.64 mm x 14.04 mm; Max rate = 100Hz; QE (400nm) = 0.3, QE (550nm) = 0.57, QE (900nm) = 0.14 * Backup options * Andor 1 MPix (1024 x 1024) 888 iXon EMCCD camera from Christoph Baranec (with 'BV' quantum efficiency option) * 13 um pixels; 13.31 mm x 13.31 mm; Max rate = 10Hz (full frame); QE (400nm) = 0.6; QE (550nm) = 0.96, QE (900nm) = 0.48 * CCD21 (1024 x 1024) custom former DBSP red channel camera * ? um pixel; Max rate = Slow; Mature science GUI; pretty good CCD QE, but not particularly red-sensitive ---+++++ TMAS foci * Channel 1 (ZMX Config 2): F/26.392; f = 134.072m; 10 mas / pixel = 10 mas / 6.5 um = 1.5385 mas/um = 1.5385 "/mm or 0.65 mm/ " (assuming NEO camera) * Nyquist at lambda = 492nm; !FoV = 25.6" x 21.6" * Channel 2 (ZMX Config 1): F/16.495; f = 83.796m; 16 mas / pixel = 16 mas / 6.5 um = 2.4615 mas / um = 2.4615 "/mm or 0.406 mm/ " (assuming NEO camera) * Nyquist at lambda = 788nm, !FoV = 41.0" x 34.6" * Same focus would have 32 mas / pixel = 32 mas / 13 um; !FoV = 32" x 32" assuming 888 iXon camera * Alt focus 1: (ZMX Config 3) F/52.784; f = 268.144m; 10 mas / pixel = 10 mas / 13 um = 0.7693 mas/um = 0.7693 "/mm or 1.3 mm/ " (assuming 888 iXon camera) * Nyquist at lambda = 492nm; !FoV = 12.8" x 10.8" * Alt focus 2a: F/32.990; f = 167.592m; 16 has / pixel = 16 mas / 13 um = 1.2308 mas / um = 1.2308 " / mm or 0.813 mm / " (assuming 888 iXon camera) * Nyquist at lambda = 788nm, !FoV = 20.5" x 17.3" * Alt focus 2b: F/26.392; f = 134.072m; 10 mas / pixel = 10 mas / 6.5 um = 1.5385 mas/um = 1.5385 "/mm or 0.65 mm/ " (assuming NEO camera) * Nyquist at lambda = 492nm; !FoV = 25.6" x 21.6" * Alt focus 2b is identical to Channel 1. ---+++++ MGS Calibration Defocus Requirement * We'd like to be able to move one of the cameras in and out of focus enough to generate > 200 pixels across the image. With the larger 13um pixels, this means a spot size that is > 2.6 mm in diameter. At the slower F/42 focus, this would be about +- 100 mm of travel. Newport makes a UTS 150, which could do +- 75 mm, which would give ~ 150 pixels across. I think this will be okay to calibrate our 64 actuators across the pupil (and at F/26 would be more than enough). So, we decide on the UTS 150. ---+++++ AO modes * S64 = 64 x 64 subaperture AO correction, limiting mag R ~ 7 provides 0.6um SR ~ 10%, 0.8um SR ~ 20%, FWHM < 0.2" at 35" off-axis * S32 = 32 x 32 subaperture AO correction, limiting mag R ~ 10 provides visible FWHM < 0.2" on-axis, ~0.3" at 35" off-axis * S8 = 8 x 8 subaperture AO correction, limiting mag R ~ 17 provides visible FWHM ~ 0.4" on- or off-axis ---+++++ AO beamsplitters * 50/50 beamsplitter * 80/20 visible (trans/refl) + long pass beyond 970nm (TBC) * 650 nm long pass * 750 nm long pass (TBC) * 970 nm long pass ---+++++ SNR calculations * Are captured in spreadsheet megyeri:\\My Documents\COO\Projects\TMAS\Systems Engineering\SNR calculator.xls * 1 hr Neo integration captured at 30Hz; 1 e- read noise; 20% spectral bandwidth; r' band; 10% Strehl ratio; 25% total efficiency (incl. qe) * Implies SNR = 10 on AB = 23.7 (4700 source cnts / sqrt(108,000) noise cnts) ---+++++ TMAS observing modes | *Mode Number* | *AO config* | *F/43 focus* | *F/11 focus* | *Science Case* | | 1 | S64 | Imaging filter | Acquisition | 12 mas/pixel imaging for all visible wavelengths | | ^ | ^ | ^ | ^ | AO-assisted speckle (Lucky) imaging (Hildebrandt)| | ^ | ^ | ^ | ^ | Lowest R imaging of faintest targets | | 2 | S64 or S32 | Imaging filter 1 | Imaging filter 2 | Dual-color photometry on different plate scales | | ^ | ^ | ^ | ^ | Narrow field PSF reference for wider-field astrometry | | ^ | ^ | ^ | ^ | Scattered light subtraction for extragalactic emission line science (Dekany) | | 3 | S64 or S32 | Flexure and exp. meter | Single-mode fiber | 10 cm/s precision radial velocity for exoplanet study (Johnson) | | ^ | > 650nm for WFS | < 500nm for Andor | feeding precision RV spectrograph (need to identify) | ^ | | 4 | S32 or S64 | Flexure compensation | Imaging filter 2 | Deep (long-exposure) visible imagery / galaxy morphology / UDF | | ^ | ^ | ^ | ^ | Red-channel coronagraphy (e.g. Serabyn (vortex coronagraphy)) | | 5 | S8 | TBD | GLAO w/ ~0.3" FWHM across moderate field | Astrometry survey / identification of transients contexts | | ^ | ^ | ^ | across visible wavelength | ^ | | 6 | S8 | Flexure & DAR | Dual, scrambled multi-mode fiber | 5 m/s RV of close (<2") binary stars (Johnson) | | ^ | ^ | compensation | w/ one on 2-axis stage | ^ |
This topic: Palomar/TMAS
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Topic revision: r11 - 2012-07-27 - RichardDekany
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