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NLC 2013-07-24/25

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 compact camera with limited field of view
          A ~325-35, h ~0-40; images every 15 min
Date: 2013-07-24/25

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:04  0                                  cloud to h 8
21:30:05  0                                  cloud to h 5 or 10
21:45:06  0                                  cloud to h 10
22:00:09  0                                  cloud to h 8
22:15:19  0                                  cloud to h 5, some higher patches
22:30:32  X                                  cloud to h 5, some higher patches
22:45:32  X                                  cloud to h 5, some higher patches
23:00:47  X                                  cloud to h 5, some higher patches
23:15:46  X                                  cloud to h 5, some higher patches
23:30:47  X                                  cloud to h 5, some higher patches
23:45:47  X                                  cloud to h 5, some higher patches
00:00:47  X                                  widespread cloud, reflection
00:15:47  NLC?             5                 through cloud, reflection
00:30:47  NLC              5                 through cloud, light beam from Castle
00:45:47  I,II       4     5                 through cloud, light beam from Castle
01:00:47  I,II       4     5                 through cloud
01:15:26  I,II       4     5                 through cloud
01:30:26  I,II       4     5                 through cloud
01:45:53  I,II       2                       through cloud
02:00:54  X                                  almost overcast
02:15:32  X                                  almost overcast
02:30:19  X                                  almost overcast
02:45:09  X                                  overcast
03:00:06  X                                  overcast
03:15:05  X                                  overcast
03:30:05  X                                  overcast

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: 2013/07/24-25
Start: 00:15
End: 01:45
Forms: I,II
Max elevation: 5
Max brightness: 4
Comments:
<a href="http://www.chiandh.me.uk/nlccam/20130724-25.shtml">Images</a>.
Through cloud.

forms: I: veil
       II: bands
       III: waves
       IV: whirls
       NLC: 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)
-------- ------ ----- ----- ----- -----  ----- -------------------
00:15:47 15.000 359.2 -14.4  -4.6   4.9  0-255 q7596.jpg
00:30:47 15.000   2.8 -14.4  -4.6   5.0  0-255 q7602.jpg
00:45:47 15.000   6.4 -14.2  -4.5   5.3  0-255 q7608.jpg
01:00:47 15.000  10.1 -13.9  -4.3   6.0  0-255 q7614.jpg
01:15:26  8.000  13.6 -13.5  -4.1   7.0  0-255 q7619.jpg
01:30:26  8.000  17.2 -12.9  -3.8   8.5  0-255 q7625.jpg
01:45:53 15.000  20.8 -12.2  -3.3  11.1  0-255 q7633.jpg

exp: Exposure time in seconds (200 ISO, f/2.8).
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).