Archive for March, 2009

Elevation Tracking for Third Trimester of 2008

The MMTO MySQL database was queried for routine tracking and weather data for the final trimester of 2008 (Sept-Dec). These data are presented with discussion of data sources, their distribution over various dimensions of the data, and appropriate statistics are shown for the purposes of evaluation of the tracking performance of the latest iteration of the elevation servo (e.g. the version released after Summer 2008 Shutdown).

 

The figures that follow and the figures in the full text are available via the web at http://tinyurl.com/cop6v8 if closer study is desired.   

Histogram of RMS error using guarded data. The boxplot below shows the median and IQR (25th to 75th percentiles).

Figure 1

Figure 2

Figure 2

 

 
 

 

 

 

To read the full text technical memorandum, click here

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MMT February Observing Statistics

    Time Summary

Percentage of time scheduled for observing              100.0
Percentage of time scheduled for engineering              0.0
Percentage of time scheduled for sec/instr chan           0.0
Percentage of time lost to weather                           38.8
Percentage of time lost to instrument                         0.2
Percentage of time lost to telescope                           0.3
Percentage of time lost to general facility                   0.2
Percentage of time lost to environment (non-weather)   0.0
Percentage of time lost                                           39.4

Breakdown of time lost to telescope: broken mount miniserver, hacksaw crash;
Breakdown of time lost to general facility: hoseclamp reboot;

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MMT Sep – Dec ’08 Trimester Summary Report

To read the MMT September – December ’08 Trimester Summary Report,
click here.

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Preparing for NASA’s LCROSS mission

During Monday’s (3/2/9) engineering night Shawn Callahan, Morag Hastie, Tim Pickering, Phil Hinz, and Ale Milone tested the f/15 AO system capabilities to develop procedures to image lunar impact craters for the upcoming NASA LCROSS mission. To learn more about this interesting NASA mission go to: http://lcross.arc.nasa.gov/

On this mostly clear evening, the moon’s illumination was less than 50% causing polar LCROSS impact craters to be unlit. We used JPL’s HORIZONS software and scripts from Tom Trebisky to generate ephemerides for the moon. As soon as we began non-sidereal tracking the center of the moon we offset to the cusp at the northern intersection of the bright limb with the terminator. This region of the moon has several mountains and crater walls in the dark limb tall enough to catch the first rays of sunrise.

The AO system was able to lock onto one glowing oblong shaped mountain top. We were all treated to see amazing lunar images free of most atmospheric distortions while looking through 2.7 airmass (22 degrees elevation angle). This was a first for the MMT!

We tried locking onto various other moonscapes with less contrast but were unsuccessful before the rapidly setting moon prevented further observations. Regrettably our efforts did not leave enough time to capture these beautiful images of the moon with the AO system locked. (Next time!) Further testing is required to determine if we can lock the AO system on the candidate craters.

The LCROSS craters shall be illuminated during our next engineering run in early April. During this run we plan to use the f/9 and/or f/5 telescope configuration to test and verify our procedures for locating and tracking each candidate impact site.

The LCROSS mission is scheduled to impact August 28th at 4:39 UTC (21:39 MST). On this evening, sunset at the MMT is 18:52, and the moon sets at 00:27. The moon shall be at an elevation angle of 42 degrees (1.5 airmass) during impact.

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