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NLC 2011-07-09/10

BAA report

The report to the BAA Aurora Section gives an overview of the night, which times were cloudy, free of NLC, or with sightings of NLC.

Name of observer: Horst Meyerdierks
Location: Royal Observatory Edinburgh, 55.9N 3.2W
          unattended dSLR with limited field of view A ~325-35, h ~0-40
          images every 15 min
Date: 2011-07-09/10

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:30  0                                  cloud to h 8
21:45  0                                  cloud to h 6
22:00  0                                  cloud to h 5
22:15  I,II        1   16       355  >35
22:30  I,II        2   19       330  >35
22:45  I,II        3   19      <325  >35
23:00  II,III      3   20      <325  >35
23:15  III,IV      3   17      <325  >35
23:30  I,III       3   15      <235  >35
23:45  I,IV        4   10            >35  cloud on left
00:00  NLC         4                      through cloud
00:15  I,IV        4   10                 through cloud
00:30  I,III       5   11                 through cloud
00:45  III         5   12                 through cloud
01:00  III         5   13                 through cloud
01:15  NLC         5   17                 through cloud
01:30  NLC         5   18                 through cloud
01:45  I,II        5   20                 through cloud, overexposed
02:00  I,II,III    5   25                 through cloud, overexposed
02:15  I,II,III    3  >40                 cloud below, overexposed
02:30  II,III      2   35
02:45  II          1
03:00  0

forms: I: veil
       II: bands
       III: waves
       IV: whirls
       NLC: other than or multiple of I-IV
       0: no NLC
       X: no decision possible (mist, cloud etc.)
brightness: 1: very weak
            2: clearly detected
            3: clearly visible
            4: very bright
            5: extremely bright

NLCnet report

The periods of positive sightings of NLC are reported to the NLC Observers' Home Page:

Name: Horst Meyerdierks
Country: Scotland
Location: Edinburgh
Date: 2011/07/09-10
Start: 22:15
End: 02:45
Forms: I,II,III,IV
Max elevation: >40
Max brightness: 5
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2011-07-09/10">Images</a>.

forms: I: veil
       II: bands
       III: waves
       IV: whirls
       O: other than or multiple of I-IV
brightness: 1: very weak
            2: clearly detected
            3: clearly visible
            4: very bright
            5: extremely bright

Images

Listed below are the images with positive sightings of NLC. These have been processed merely to adjust the brightness for underexposure. For some, there may also be an unsharp-masked version of the image.

  UT    exp    A    hSun  h15   h85  stretch  image      (masked)
----- ------ ----- ----- ----- -----  ----- ---------------------
22:15  0.300 331.5  -7.5   0.1 155.5  0-255 q15377.jpg m15377.jpg
22:30  0.600 334.9  -8.5  -0.8 128.9  0-255 q15379.jpg
22:45  1.300 338.3  -9.3  -1.4  69.8  0-255 q15381.jpg
23:00  2.000 341.7 -10.0  -1.9  35.7  0-255 q15384.jpg
23:15  2.000 345.2 -10.6  -2.3  23.6  0-255 q15387.jpg
23:30  2.500 348.7 -11.1  -2.6  18.2  0-255 q15391.jpg
23:45  4.000 352.2 -11.5  -2.9  15.4  0-255 q15396.jpg
00:00  4.000 355.7 -11.7  -3.0  14.0  0-255 q15401.jpg
00:15  2.500 359.3 -11.8  -3.1  13.4  0-255 q15405.jpg
00:30  1.300   2.8 -11.7  -3.0  13.6  0-255 q15409.jpg
00:45  1.000   6.4 -11.6  -2.9  14.7  0-255 q15414.jpg
01:00  0.800   9.9 -11.3  -2.8  16.8  0-255 q15419.jpg
01:15  1.000  13.4 -10.9  -2.5  20.8  0-255 q15424.jpg
01:30  0.800  16.9 -10.3  -2.1  29.2  0-255 q15428.jpg
01:45  0.800  20.3  -9.6  -1.7  50.6  0-255 q15432.jpg
02:00  0.800  23.8  -8.8  -1.1 106.0  0-255 q15435.jpg
02:15  0.400  27.2  -7.9  -0.3 147.6  0-255 q15437.jpg
02:30  0.167  30.5  -6.9   0.8 162.3  0-255 q15439.jpg
02:45  0.067  33.8  -5.8   2.6 169.1  0-255 q15441.jpg m15441.jpg

exp: Exposure time in seconds (400 ISO, f/3.5).
A: Azimuth of the Sun (degrees).
hSun: Altitude of the Sun (degrees, negative below horizon).
h15: Max. altitude of sunlight at 15 km height (degrees).
h85: Max. altitude of sunlight at 85 km height (degrees).
stretch: Contrast stretch (0-255 means no stretch).