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NLC 2010-07-23/24

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: Stichill Eastfield, 55.7N 2.4W
          unattended dSLR with limited field of view A ~310-20, h ~0-40
          images every 15 min
Date: 2010-07-23/24

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:15  X                                  only few clear areas
21:30  X                                  cirrus to h 7, cumulus on right
21:45  X                                  cirrus to h 8
22:00  X                                  cirrus to h 10, some higher patches
22:15  X                                  cloud in various parts of field
22:30  X                                  cirrus to h 20
22:45  X                                  cirrus to h 25
23:00  X                                  cirrus to h 20 or 25
23:15  X                                  cirrus to h 30
23:30  II          2    3      <350   >0  through cloud
23:45  II          2    4      <350   >5  through cloud
00:00  NLC?             3                 through cloud
00:15  NLC?             4                 through cloud
00:30  NLC         2    4                 through cloud
00:45  NLC         3    4      <340  >15  through cloud
01:00  NLC         4    5      <340  >15  some cloud in front
01:15  NLC         4    6       350  >15  some cloud in front
01:30  I,II        4    7       335  >15  some cloud in front
01:45  I,II        5    8       335  >15  some cloud in front
02:00  I,II        4    8       330  >15  almost clear
02:15  I,III       4    9      <330  >15  almost clear
02:30  I,III       3    9      <330  >15  some cloud in front
02:45  NLC?        1                      some cloud in front
03:00  X                                  cirrus to h 10
03:15  X                                  cirrus to h 10 or 15
03:30  X                                  cirrus to h 20

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: Stichill
Date: 2010/07/23-24
Start: 23:30
End: 02:45
Forms: I,II,III
Max elevation: 9
Max brightness: 5
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2010-07-23/24">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
23:30 30.000 348.8 -13.8  -4.3   6.3  0-255 q32584.jpg
23:45 30.000 352.4 -14.1  -4.4   5.5  0-255 q32590.jpg
00:00 30.000 356.1 -14.3  -4.6   5.1  0-255 q32596.jpg
00:15 30.000 359.7 -14.4  -4.6   4.9  0-255 q32602.jpg
00:30 30.000   3.3 -14.4  -4.6   5.0  0-255 q32608.jpg
00:45 30.000   7.0 -14.2  -4.5   5.4  0-255 q32614.jpg
01:00 30.000  10.6 -13.9  -4.3   6.1  0-255 q32620.jpg
01:15 15.000  14.2 -13.4  -4.0   7.2  0-255 q32625.jpg
01:30 15.000  17.8 -12.8  -3.7   8.9  0-255 q32631.jpg
01:45  6.000  21.3 -12.1  -3.3  11.6  0-255 q32636.jpg
02:00  6.000  24.8 -11.3  -2.8  16.6  0-255 q32642.jpg
02:15  3.200  28.3 -10.4  -2.2  28.2  0-255 q32646.jpg
02:30  2.500  31.7  -9.3  -1.4  70.9  0-255 q32649.jpg m32649.jpg
02:45  0.500  35.0  -8.1  -0.5 142.3  0-255 q32650.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).