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NLC 2015-07-23/24

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: 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: 2015-07-23/24

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:01  0
21:30:01  0
21:45:02  0
22:00:03  0
22:15:19  II         3    10        25  >35
22:30:18  II         3    10        10  >35
22:45:32  II         4     8         5  >35
23:00:53  II         3     7       355  >35
23:15:47  I          4     8       345  >35
23:30:47  I          4     4        20  >35
23:46:24  I          2     5        20  >35
00:01:24  I          2     5        20   35
00:15:47  I          2     4        20   35
00:31:24  I          2     4        20   35
00:46:24  I          2     4       325   35
01:00:47  I          3     5       325   25
01:15:46  I          4     5       330   20
01:30:47  I          4     6       335   20
01:45:53  I          4     7       340   15
02:00:32  I          3                       through cloud
02:15:18  I          2                       through cloud
02:30:09  X                                  cloud
02:45:07  0
03:00:01  0
03:15:01  0
03:30:01  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: 2015/07/23-24
Start: 22:15
End: 02:15
Forms: I,II
Max elevation: 10
Max brightness: 4
Comments: Some cloud.
http://www.chiandh.eu/nlccam/20150723-24.shtml

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)
-------- ------ ----- ----- ----- -----  ----- -------------------
22:15:19  4.000 330.6  -9.7  -1.7  48.1  0-255 q5376.jpg
22:30:18  4.000 334.0 -10.7  -2.4  23.2  0-255 q5379.jpg
22:45:32  8.000 337.6 -11.5  -2.9  14.8  0-255 q5384.jpg
23:00:53 15.000 341.2 -12.3  -3.4  10.8  0-255 q5391.jpg
23:15:47 15.000 344.7 -12.9  -3.7   8.6  0-255 q5396.jpg
23:30:47 15.000 348.3 -13.4  -4.0   7.2  0-255 q5402.jpg
23:46:24 30.000 352.1 -13.8  -4.3   6.3  0-255 q5409.jpg
00:01:24 30.000 355.7 -14.0  -4.4   5.8  0-255 q5415.jpg
00:15:47 15.000 359.2 -14.1  -4.4   5.6  0-255 q5420.jpg
00:31:24 30.000   2.9 -14.1  -4.4   5.6  0-255 q5427.jpg
00:46:24 30.000   6.6 -13.9  -4.3   6.0  0-255 q5433.jpg
01:00:47 15.000  10.0 -13.6  -4.1   6.7  0-255 q5438.jpg
01:15:46 15.000  13.6 -13.2  -3.9   7.8  0-255 q5444.jpg
01:30:47 15.000  17.2 -12.6  -3.6   9.6  0-255 q5450.jpg
01:45:53 15.000  20.8 -11.9  -3.2  12.6  0-255 q5457.jpg
02:00:32  8.000  24.2 -11.2  -2.7  17.8  0-255 q5462.jpg
02:15:18  4.000  27.6 -10.2  -2.1  30.3  0-255 q5466.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).