From: Chris Shelton Date: June 2, 2006 10:05:49 AM PDT To: Antonin Bouchez , "'John Angione'" Cc: Mitchell Troy , "'Viswa Velur'" , Ed Kibblewhite Subject: Re: BTO 6/1/06 update Reply-To: Jean.C.Shelton@jpl.nasa.gov Antonin, Wow, you got a lot done. Do you want to go down together or separately or at all on Monday? I made reservations for two nights, on the theory that we might be ready to move the telescope late Monday, but may need Tuesday. I think I have easily two days of work. Here's a to do list, at least what I can remember. Is there anything else you can think of? Finish the "tasks left for next week" from your email (below). Find waveplate zero position, record it in Default file. Check Q1, Q2 signal levels at zenith Add Q2 baffle, or at least check Q2 alignment as we did for Q1. Recheck signal levels at zenith, test and debug if needed all remaining lock modes Insert polynomial correction on m2_x and m2_y Move telescope, check signal levels and polynomial correction vs pointing. Add and test separate loop-dropout and safety thresholds (red, yellow thresholds) Test interactions with safety system (test of pieces -- full test requires yellow beam, LLT). In your original alignment, how did you go about establishing the coude end of the polar axis? You explained how you spun the telescope to get the upper end. I'll also coordinate with John A. When is there likely to be a yellow beam? An LLT? Cheers, Chris Antonin Bouchez wrote: > All, > > I just returned from a long day at Palomar. Here's what I got done > on the BTO: > (I will also post this on the TWiki site BTO page...) > > 1. Checked stability and alignment of BTO Coude breadboard > > The new breadboard has been mounted to the spectrograph frame using > a single wide steel L-bracket along the lower edge. While > alignment is good, I'm somewhat concerned about vibrations. A > diagonal brace behind might be necessary to stiffen the mount, but > this is not an immediate priority. The breadboard surface is > parallel to the polar axis to better than 0.10 deg., and parallel > to the vertical plane to ~0.2 degrees (the top leans very slightly > East). The surface is 3.50" from the polar axis, making this the > beam height on the breadboard. No shimming was necessary. > > 2. Define polar axis > > I mounted an iris on the new breadboard, centered on the polar axis > as defined by the 635nm diode laser installed last week. This > laser allowed us to transfer the knowledge of the location of the > polar axis from the old breadboard to the new one. I expect this > iris is within ~3mm of the true polar axis. The other point > defining the axis is the center of the Coude output window (well, > not exactly the center - actually a point 2/3 of the way up, along > the central axis). > > 3. Simulate CSFL beam > > I set up an unpolarized HeNe laser to reflect off a mirror placed > in front of the CSFL shutter, to replicate the geometry of the > yellow laser for alignment and testing. > > 3. Populate BTO Coude breadboard. > > I installed all optics, stages, and the 660nm polarized diode laser > on the new breadboard. These were aligned to the simulated CSFL > beam and polar axis. The simulated CSFL and 660nm beams are now co- > aligned, and reflect off the FSM onto the polar axis. I took some > photos of the setup, but my camera apparently doesn't feel like > showing them off right now. > > NOTE: I may have installed the 1/2-wave plate rotary stage > backwards from its previous orientation due to mounting > constraints. If this is the case, a sign will have to be changed > in the software controlling this motor. > > Tasks left for next week: > > I ordered a few small parts which will simplify some of the > optomechanics - these should arrive at Palomar tomorrow (6/2). > After installing these, we should be ready to test the Q1 and Q2 > signal levels with the 660nm laser. This will be a repeat of the > testing Chris and John did 2 weeks ago, with new optics on the > Coude breadboard, the enhanced-Al mirror on the trolley, and RG610 > filters in front of quad cells - all are in hand. Other than this, > I don't think there is really much more to do until we have yellow > light to work with. I will discuss with Viswa when we might be > able to do this. > > Sincerely, > > Antonin > > ---------------------------------------- > Dr. Antonin Bouchez > Adaptive Optics Lead > Caltech Optical Observatories > (626) 395-8915 > -- Chris Shelton, Ph.D Principal Engineer Interferometry and Advanced Optical Systems Section 383 Jet Propulsion Laboratory 4800 Oak Grove Drive, M/S 171-113 Pasadena, CA 91109 818 354 2871 office 818 645 7137 cell Jean.C.Shelton@jpl.nasa.gov