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MMT primary mirror coating removed for re-aluminization

The 6.5-meter MMT primary mirror was stripped of its aluminum coating on July 23, 2010, in preparation for re-aluminization. A video of the mirror stripping can be seen at:

Removal of the aluminum coating is done with a series of scrubbing and rinsing treatments, using ordinary mops, paper towels, various cleansers, solutions, and water.  Great care must be taken to remove all of the existing aluminum coating as well as any contaminants from the mirror surface.

Unlike many other mirrors, the MMT is re-aluminized in situ with the mirror remaining on the telescope within its mirror cell during the entire aluminization process.  The mirror is enclosed in a large (>20-foot  diameter) vacuum bell jar from which all air and contaminants are removed.  Aluminum filaments are then vaporized, depositing a thin, even coating of reflective aluminum across the mirror face.

Although the aluminization event itself occurs in less than a second, weeks of preparation are required prior to the event.  Much of the hardware and electronics within the mirror cell must be removed prior to vacuum sealing.  All surfaces that will be inside the vacuum chamber must be thoroughly cleaned.  The hardware is then reassembled after aluminization and prior to any telescope operations.  The previous re-aluminization of the MMT primary mirror occurred in 2005.

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MMT December Observing Statistics

Percentage of time scheduled for observing               90.0
Percentage of time scheduled for engineering            10.0
Percentage of time scheduled for sec/instr change       0.0
Percentage of time lost to weather                            37.8
Percentage of time lost to instrument                          2.6
Percentage of time lost to telescope                           7.1
Percentage of time lost to general facility                    0.1
Percentage of time lost to environment (non-weather)   0.0
Percentage of time lost                                            47.6

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Breakdown of hours lost to telescope:
10.25  Hexapod failure
  7.30  M2 (f/15) problems
  7.00  AO software
  0.50  Gap contamination
  0.50  Thin Shell Safety (TSS) issues

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Research Using the MMT in the News

From observations made using the MMT, Dr. E. Mamajek of the University of Rochester has discovered that the first known binary star is actually a sextuplet system.   To read the article published by Science Daily, press here.

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MMT November Observing Statistics

Percentage of time scheduled for observing             93.4
Percentage of time scheduled for engineering            6.6
Percentage of time scheduled for sec/instr change    0.0
Percentage of time lost to weather                          22.3
Percentage of time lost to instrument                        0.4
Percentage of time lost to telescope                         2.8
Percentage of time lost to general facility                  0.0
Percentage of time lost to environment (non-weather) 0.0
Percentage of time lost                                          25.5

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Breakdown of hours lost to telescope:
7.0 Hexapod
1.0 WFS
1.0 Guider issues
0.5 M1 panic
0.3 Unable to flatten f/15

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MMT October Observing Statistics

Percentage of time scheduled for observing           100.0
Percentage of time scheduled for engineering           0.0
Percentage of time scheduled for sec/instr change    0.0
Percentage of time lost to weather                         37.5
Percentage of time lost to instrument                       7.3
Percentage of time lost to telescope                        2.6
Percentage of time lost to general facility                  0.0
Percentage of time lost to environment (non-weather) 0.0
Percentage of time lost                                          47.3

—————
Breakdown of hours lost to telescope:

3.9   f/15 loop
1.5   Elephant hose replaced
1.0   Hexapod
2.25 WFS

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MMT September Observing Statistics

Percentage of time scheduled for observing             96.7
Percentage of time scheduled for engineering            3.3
Percentage of time scheduled for sec/instr change     0.0
Percentage of time lost to weather                          26.3
Percentage of time lost to instrument                        0.1
Percentage of time lost to telescope                         3.7
Percentage of time lost to general facility                   0.0
Percentage of time lost to environment (non-weather)  0.0
Percentage of time lost                                           30.0

—————
Breakdown of hours lost to telescope:

3.5  WFS 
5.05 f/15 issues 
2.3  SO guider camera

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MMTO All Sky Camera Used to Identify Ice Crystal Halos

According to a recent blog entry, the MMTO all sky camera data has been mined to identify ice crystal halos. For more details see the blog entry by following the link below:

MMTO Ice Crystal Halos

MMTO All Sky Camera Halos

MMTO All Sky Camera Halos

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