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NLC 2011-07-01/02

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: 2011-07-01/02

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:45  0                                  cloud to h 10
22:00  0                                  cloud to h 10
22:15  0                                  cloud to h 10, fake NLC (cirrus)
22:30  0                                  cloud to h 10, fake NLC (cirrus)
22:45  0                                  cloud to h 10, fake NLC (cirrus)
23:00  0                                  cloud on right to h 12, fake NLC
23:15  X                                  fake NLC, real NLC possible
23:30  IV         2    14      <330  >30  NLC diffuse, fake NLC above
23:45  III,IV     3    15      <325  >35  NLC diffuse, fake NLC above
00:00  III,IV     3    15      <325  >35  NLC diffuse, partly through cloud
00:15  III,IV     3    17      <325   25  NLC diffuse, partly through cloud
00:30  III,IV     3    17      <325  >30  partly through cloud, fake NLC above
00:45  IV         3    16      <325       NLC no longer diffuse, partly through cloud
01:00  III,IV     3    18      <325  >30  some cloud on right
01:15  I,II       3    21      <325       some cloud on right
01:30  II         3    23      <325  ~25  some cloud on right
01:45  II         2    35      <325   35  no cirrus, hence high NLC unlikely to be fake
02:00  III        1    30      <325   30
02:15  NLC?       1                       dawn
02:30  0
02:45  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: 2011/07/01-02
Start: 23:15
End: 02:15
Forms: I,II,III,IV
Max elevation: 35
Max brightness: 3
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2011-07-01/02">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
22:30  0.300 335.4  -7.8  -0.2 150.5  0-255 q14865.jpg
22:45  0.600 338.8  -8.6  -0.9 120.4  0-255 q14867.jpg
23:00  1.300 342.2  -9.3  -1.4  68.2  0-255 q14869.jpg
23:15  2.000 345.6  -9.9  -1.9  39.2  0-255 q14872.jpg
23:30  3.200 349.1 -10.4  -2.2  27.7  0-255 q14876.jpg
23:45  4.000 352.6 -10.7  -2.4  22.5  0-255 q14880.jpg
00:00  5.000 356.1 -10.9  -2.5  20.1  0-255 q14884.jpg
00:15  5.000 359.6 -11.0  -2.6  19.2  0-255 q14888.jpg
00:30  5.000   3.1 -11.0  -2.5  19.7  0-255 q14892.jpg
00:45  4.000   6.6 -10.8  -2.4  21.8  0-255 q14896.jpg
01:00  3.200  10.1 -10.5  -2.2  26.1  0-255 q14900.jpg
01:15  2.000  13.6 -10.0  -1.9  35.6  0-255 q14903.jpg
01:30  1.300  17.1  -9.5  -1.5  58.8  0-255 q14905.jpg
01:45  0.800  20.5  -8.8  -1.0 108.9  0-255 q14907.jpg
02:00  0.400  23.9  -8.0  -0.4 145.8  0-255 q14909.jpg m14909.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).