Caltech Optical Observatories Cahill Reference TWiki

Cahill Center for Astronomy and Astrophysics

General Instrumentation Meetings and Workshops

COO Lunch Time talks

Talks have been suspended until ~mid Oct due to conflicts with ZTF commissioning and travel ...

TBD Michael Feeney JT Cooler Survival Guide Michael tells how we escaped from the grips of Polycold, an unreliable and expensive supplier, by developing in-house capability to diagnose and fix Cryotiger problems, find alternate sources, and refurbish used parts.
TBD Smith and Kaye Waveform Definition Language We have a powerful new tool, a Waveform Compiler that interprets timing rules written in whatever order the user likes in a matter of seconds, it configures the controller to make those waveforms happen, or plots them. A mechanism is provided for the compiler to produce messages to the host software (the waveforms are loaded into the controller) so the detector engineer can create a single point of control.
TBD Smith & Kaye Optmizing ZTF readout speed Squeezing the most out of the pixel time to maximize noise averaging at 1 MHz pixel rate, or to go even faster.
TBD Roger Smith ZTF window Heater Thermal modelling shows that ZTF window will frost up. Come hear about how our AR coating provides >30W of make up heat. We'll also look at some other radiative transport issues for ZTF, such as whether the schmidt corrector will ever fog up?
TBD Steve Kaye ZTF CCD Performance A tour of key CCD performance metrics. How does one make such measurements? How much variation is there among the 64 science channels for ZTF ?

TBD Jamey Ericksen Turning 60 and faster than ever Jamey will tell us about the upgrades of the venerable 48" Schmidt, now 60 years old, to slew and settle in less than ZTF's 9.4 sec CCD readout time. New motors, servo's and software. New dome drive and smarter algorithms. Structural resonances to dodge and and subtle drive train and balance issues.
TBD Peter Mao ZTF Controller Performance Highlights from our testing campaign. What it took to assure all channels are working and optimized.

Proposed for future:

TBD Alex Delacroix Window Supporting 2 Tons The optical design for ZTF wants the window to be thinner, but if it fails it kills the instrument and we are all going to be unemployed. Come find out how we achieved adequate safety margin for this brittle component, that has to support 2 tons of atmosphere.
TBD Rich Dekany ZTF Focal Surface Metrology Deviations of ZTF CCDs from the spherical focal surface delivered by the 48" schmidt have been measured on-sky using classic through-focus scans and extra-focal image analysis. Both methods survive testing with elaborate artifical data, incorporating aberrations, diffraction, beam obstructions and vignetting by primary. Results differ somewhat but both report similiar unexplained curvature. Bring your ideas.
TBD Roger Smith Vacuum Advice What's important? What's not? How much to pump and how seldom. Initial cleaning and baking. Use a leak detector as your pumping station, but don't do stupid stuff. Cold traps. Underlying physics. Vital roles of getters and desiccants. Gauge types and ion pumps. How your cooling system affects all this.
TBD Michael Porter Robotic filter exchanger Our first experience using an industrial robot in an astronomical instrument. Latches for ultra-secure hand off. Robot setup to maximize safety. Validation methods.
TBD Rich Dekany ZTF Optical Design DIQ budget. Why the ZTF approach with CCDs faceted on spherical surface with local field flatteners had to be used instead of the simple plano-convex window used in PTF. Why add a third corrector element? Current status and performance.
TBD TBD ZTF Flat Field Illuminator In a quest for greater photometric precision, the ZTF flat field screen has been enclosed, baffled and sealed to the telescope to block stray light. A ring of LEDs facing a white screen has programmable intensity for each of 14 colors. Forward voltage is recorded to allow compensation for efficiency changes with junction temperature.

Suggestions for talks? Roger Smith,

Universities Space Research Association

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Topic revision: r64 - 2017-09-20 - RogerSmith
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