From toomey@ifa.hawaii.edu Thu Sep 19 09:50:42 2002 Date: Wed, 18 Sep 2002 15:46:22 -1000 From: Douglas Toomey To: techgroup@jeans.ifa.hawaii.edu Subject: Eng run results [The following text is in the "iso-8859-1" character set] [Your display is set for the "US-ASCII" character set] [Some characters may be displayed incorrectly] One of the key goals was to make sure that we could reproduce the results of the last run to make sure that we understood what had worked. We were successful in doing that. The system worked very much like the last run and we were able to confirm that the significant change that gave us the performance last run was taking the interaction matrix with the mirror flattened by a set of static voltages. We were able to achieve images around 0.2 to 0.3 arcseconds FWHM most of the night. The seeing varied from .5 to .7 arcseconds FWHM. The Strehls were about 20-25%. This is still below the expected performance. The two remaining problems we are tracking down are a low closed loop bandwidth and a small tilt correction error at about the 0.1 arcsecond level or less. We also checked performance versus guide star brightness. We could lock on and guide down to about 14th and still have a little improvement. Please do not quote this number as a sensitivity limit. Just because we can lock on does not mean that there is a worthwhile improvement. But it is safe to say that the 10th magnitude limit that we have been quoting is no problem. These images can be seen at /benchmark/AO/020917 look in the readme file. We also did a star at 45 degrees zenith angle 1.24 airmass star and the system worked well and there was no apparent flexure. These were both just quick tests but were encouraging. Also we had to roll NSFCAM out after the first night and then back in for the second night and the alignment was preserved. Doug