Here are the basic transmission factors for the NGAO point design (as currently envisioned): *Telescope transmission (H-band)* # of mirrors (exposed) 3 @ 0.85 = 0.614 (<-- replace w/ measured value) *NGAO Optical Relay* # of mirrors (Al) 5 @ 0.97 = 0.859 (4 mirror relay + 1 turning mirror)<p> # of air/glass 6 @ 0.98 = 0.886 (double input window + dichroic)<p> (assume AR coat for NIR)<p> Subtotal 0.761<p> *IR-MOS (IR multi-object AO spectrograph)* # of mirrors (Al) 4 @ 0.97 = 0.885 (object-selection mechanism)<p> # of mirrors (Au) 7 @ 0.985 = 0.900 (cryostat)<p> # of vacuum/glass 10 @ 0.988 = 0.886 (5 lenses, NIR coated)<p> Grating efficiency 1 @ 0.60 = 0.600<p> Filter efficiency 1 @ 0.90 = 0.900<p> Subtotal 0.381<p> IR array H-band QE 0.850 (2.5um cut-off HgCdTe)<p> Subtotal 0.324<p> *Visible Imager* # of mirrors (Al) 2 @ 0.97 = 0.941 (OAP relay)<p> # of air/glass 8 @ 0.98 = 0.851 (1 window + 1 filter + 2 ADC prism)<p> ADC glass/glass 2 @ 0.99 = 0.980<p> ADC absorption 1 @ 0.98 = 0.980<p> Filter efficiency 1 @ 0.95 = 0.950<p> Subtotal 0.730 CCD red QE 0.850 (deep depletion CCD) Subtotal 0.621 *Summary* Transmission thru Telescope & Relay 0.47<p> Total for IR-MOS (incl. QE) 0.15 (H-band science)<p> Total for Visible Imager (incl. QE) 0.29 (R-band science)<p> -- Main.RichardDekany - 20 Apr 2006
This topic: Keck/NGAO
>
TransmissionBudget
Topic revision: r1 - 2006-04-21 - RichardDekany
Copyright © 2008-2024 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki?
Send feedback