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SALT 2012-1 Semester Report: seeing

SALT 2012-1 Semester Report: seeing . 2012-1: 1 May – 31 Oct. 2011-2: 1 Sep – 30 Apr. Median = 1.66”. Median = 1.38”. Seeing values consistently worse than expected from long term DIMM measurements: Old SAAO DIMM (1994-2000) gave median 0.9”

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SALT 2012-1 Semester Report: seeing

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  1. SALT 2012-1 Semester Report:seeing 2012-1: 1 May – 31 Oct 2011-2: 1 Sep – 30 Apr Median = 1.66” Median = 1.38” • Seeing values consistently worse than expected from long term DIMM measurements: • Old SAAO DIMM (1994-2000) gave median 0.9” • New DIMMs (Mar 2010 – Mar 2011) gave median 1.3” (53,938 measurements) • Difference partly attributed to different exp time (10 ms vs. 3 ms) coupled with mean • coherence time of the atmosphere at Sutherland (2.44 ms).

  2. SALT 2012-1 Semester Report:seeing vs. telescope delivered image quality Sep – Nov 2011 ~1.2x degradation between ideal seeing limited images and real telescope images. 1.1 – 1.2 x degradation between zenith seeing and seeing at telescope airmass (1.2 – 1.4) Rule of thumb: BEST expected IQ is ~1.4 x actual DIMM seeing value (for perfectly aligned primary mirror array) For 2012-1, this implies expected median IQ is 2.3”. One reason why poor seeing programs were more successful.

  3. SALT 2012-1 Semester Report:observing statistics Previous semester 2011-2 (Sep 2011 – Apr 2012):

  4. SALT 2012-1 Semester Report:completion statistics Expected total observed: 58% of 950h = 551 h Actual total observed: 408 h “Efficiency”: 74% (<100% due to overheads & rejected blocks)

  5. SALT 2012-1 Semester Report:completion statistics

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