1. PHARO (2?) James Lloyd (Cornell)

2. PHARO is the Palomar Workhorse AO Instrument Commissioned in early 1998 Built at Cornell: Tom Hayward/Bernhard Brandl JHK Imaging + spectroscopy + coronagraphy Very good optics All reflective: 2 plate scales 25 mas (Nyquist @ 1.2 mm) 40 mas (Nyquist @ 1.9 mm) 35 nm RMS WFE (Hayward et al 2001)

3. Problems with PHARO Detector Early generation HAWAII-1 (1k) Very peculiar reset anomaly Limited dynamic range Reliability of acquisition system based on SPARC-2/SunOS platform Mechanism Reliability due to cryogenic Phytron Motors

4. Aperture Masking

5. Closure Phase/SelfCal

6. Contrast vs l

7. L Band Masking @ Keck

8. L Band Masking @ Palomar

9. Upgrade PHARO? Teledyne (Rockwell) has been advertising the “H4-RG-10” as the next generation: 4k x 4k detector with 10 micron pixels a 10 micron pixel would give PHARO Nyquist sampling at l=660 nm. Current generation of HgCdTe detectors from Teledyne are available substrate removed with QE>70% to l=400 nm

10. Upgrade PHARO? This would be neat: push out l to cover the visible for P3K and the L/M bands for a masking planet survey Solve the detector problems with PHARO Solve at the same time PHARO mechanical problems and implement additional desirable capabilities. (nb there is a wrinkle that additional cooling requires a new dewar) Cornell is considering an NSF/MRI proposal to fund this upgrade

11. Options 1. 10 micron pixel detector Teledyne has fabricated Si-pin H4RG-10, but there are problems with the unit cell A H4RG-10/H2RG-10 is probably $0.8M-$1.0M development today. 2. H2RG-18 with 0.7-5.3 mm substrate removed detector: about $400k + a whole new instrument (at least another $1M) 3. H1RG-18 with 0.7-5.3 mm substrate removal. May be able to add the optics for a finer plate scale, but likely will be stuck with 25mas pixels.

12. Questions/Comments ? Will there be a role for PHARO without an upgrade? Are there other important considerations or suggestions for a PHARO upgrade?