Dear all,

please find below a short summary of the activities of the 28th related to the AO system.

People at LBTO:G. Brusa

people working from remote:A. Riccardi, M. Xompero (VNC+Skype) March 28th

Total # of person: 3

Summary:

Second night in a row with virtually no problems as far as operation of the ASM! The mirror ran

the entire night smoothly and without faults, with the exception of one actuator that 'jumped' with its position readings well outside reasonable values. But it happened at the beginnig of the night for a very short time only.

As far as control software there were the usual (a bit annoying) deaths of some of the GUIs but no major issues.

I followed the suggestion by Daniele and John and added both the Chamber temperature as well as the Outside (roof) temperature. From these data it appears that the hub is tracking very nicely the temperature of the surrounding air, with the exception of the beginning of the night (but this is probably true for most of the telescope structure).

We repeated the measurement of astigmatism as a function of elevation and confirmed the previous one, at the moment the ASM is correcting all of it (~2.5um rms surface at 20 degrees elevation, 0 at zenith, with a linear dependency from zenithal angle).

Many data were taken with active optics to try to determine collimation tables and field aberrations as a function of elevation.

Short log:

UT 01:30 heavy clouds towards West block the Sun setting.

UT 01:33 Dome is closed: -1 deg elevation, coolant flow 10.2 lit/min. Chamber Ambient 9.1 C, inlet 8.9 C, outlet 10.5 C, hub 12.0 C, cp 9.5 C, rb 10.3 C, Outside Ambient 5.8 C. Wind 0.1 m/s.

UT 01:57 Dome open. Moving to zenith. Actuator dsp#61 is now measuring 174354.

UT 02:02 the actuator dsp #61 is back. We decided to keep it in the list of ‘good actuators’. This is probably one of the flexible contacts.

UT 02:08 setting the shell.

UT 02:09 shell set.

UT 02:14 preset to Pollux

UT 02:16 tracking on Pollux, : 84 deg elevation, coolant flow 10.1 lit/min. Chamber Ambient 6.6 C, inlet 6.5 C, outlet 8.4 C, hub 9.2 C, cp 7.4 C, rb 8.6 C, Outside Ambient 6.0 C. Wind 0.7 m/s.

UT 02:30 tracking on Pollux, : 85 deg elevation, coolant flow 10.1 lit/min. Chamber Ambient 6.5 C, inlet 7.1 C, outlet 8.7 C, hub 8.6 C, cp 7.0 C, rb 7.9 C, Outside Ambient 5.9 C. Wind 1.2 m/s.

UT 02:32 tracking on M5_1210, : 27 deg elevation, coolant flow 10.1 lit/min. Chamber Ambient 6.5 C, inlet 5.5 C, outlet 8.0 C, hub 8.5 C, cp 6.9 C, rb 7.9 C, Outside Ambient 5.9 C. Wind 1.6 m/s.

UT 03:52 tracking on M5_1210, : 25 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 6.0 C, inlet 5.0 C, outlet 7.6 C, hub 6.1 C, cp 6.0 C, rb 6.2 C, Outside Ambient 5.6 C. Wind 3.3 m/s.

UT 04:49 tracking star: : 61 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.6 C, inlet 5.2 C, outlet 7.7 C, hub 6.0 C, cp 5.6 C, rb 5.9 C, Outside Ambient 5.3 C. Wind 0.7 m/s.

UT 05:31 heavy cirri that with the moon make for a significant background… Tracking object 30 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.5 C, inlet 5.6 C, outlet 7.4 C, hub 5.9 C, cp 5.4 C, rb 5.7 C, Outside Ambient 5.3 C. Wind 0.8 m/s.

UT 05:45 The star observed (30 deg el) show a significant amount of Z6 (we corrected -3000 nm), we tried the experiment of setting to zero the astigmatism applied by the ASM to see if it is the ASM to apply this amount but the heavy clouds prevented from checking the PSF

UT 06:01 Tracking Pollux (brighter star…) at 45 deg elevation, it is visible but probably 8-10 magnitudes fainter.

UT 06:05 Tracking object 45 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.7 C, inlet 5.6 C, outlet 7.4 C, hub 5.9 C, cp 5.4 C, rb 5.7 C, Outside Ambient 5.3 C. Wind 0.8 m/s.

UT 06:23 Tracking Arcturus. 51 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.7 C, inlet 4.9 C, outlet 7.0 C, hub 5.7 C, cp 5.5 C, rb 5.7 C, Outside Ambient 5.3 C. Wind 0.8 m/s.

NOTE: we verified that the primary was not applying any astigmatism and that the only one applied was by the secondary and that the PSF was reasonably free from astigmatism, i.e. the lookup table for M2 seem to work at least down to this elevation.

We tried lower elevation M5_0439 but the clouds did not allow us to see it.

UT 06:39 looking for some opening in the sky west of the meridian…

UT 06:48 Tracking 25 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.3 C, inlet 4.9 C, outlet 7.5 C, hub 5.5 C, cp 5.4 C, rb 5.7 C, Outside Ambient 4.9 C. Wind 1.4 m/s. Applied astigmatism seems to be correct -> 1.9*(1.2) um.

NOTE: We checked the astigmatism ‘by eye’ before sending the active optics correction and it looked small confirming one more time that the OL astigmatism corrections applied to M2 are correct to the first order.

UT 07:24 Tracking 65 deg elevation, coolant flow 10.2 lit/min. Chamber Ambient 5.0 C, inlet 4.5 C, outlet 6.7 C, hub 5.2 C, cp 5.0 C, rb 5.3 C, Outside Ambient 4.9 C. Wind 3.3 m/s.

UT 08:25 Tracking 70 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.5 C, inlet 5.6 C, outlet 7.3 C, hub 5.2 C, cp 5.4 C, rb 5.5 C, Outside Ambient 4.9 C. Wind 3.1 m/s.

UT 10:21 Tracking 64 deg elevation, coolant flow 10.0 lit/min. Chamber Ambient 5.5 C, inlet 5.7 C, outlet 7.3 C, hub 5.0 C, cp 5.4 C, rb 5.4 C, Outside Ambient 4.6 C. Wind 1.8 m/s.

UT 12:06 Tracking 54 deg elevation, coolant flow 9.8 lit/min. Chamber Ambient 3.3 C, inlet 2.6 C, outlet 5.0 C, hub 3.9 C, cp 3.5 C, rb 3.8 C, Outside Ambient 2.8 C. Wind 4.8 m/s.

UT 12:42 Moving down to 20 deg elevation and preparing to closed the shutters.

UT 12:47 Shutters closed, slewing to 90 deg elevation.

UT 12:50 ASM set to rest.

Ciao,

Guido

-- ArmandoRiccardi - 02 Apr 2010
Topic revision: r1 - 02 Apr 2010, ArmandoRiccardi
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