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NLC 2018-07-29/30

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: 2018-07-29/30

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:00:01  X                                  widespread cloud
21:15:02  0                                  some cloud
21:30:05  NLC        1    20       350   30  cloud below, some above
21:45:09  II,IV      2    40       325   30  some cloud patches
22:00:19  II,IV      2    30      <325   35  some cloud patches on right
22:15:32  II,IV      3    20      <325       some cloud patches on right
22:30:53  II,IV      3    15      <325   25  some cloud patches
22:46:25  IV         3    12      <325   20  some cloud patches
23:01:24  IV         3    10      <325       through cloud
23:16:24  NLC        3     5                 through cloud
23:31:24  NLC        3     5                 through cloud
23:46:24  NLC        2                       through cloud
00:01:24  X                                  widespread cloud
00:16:24  X                                  cloud to h 15 or 20
00:31:25  X                                  cloud to h 10 or 15
00:46:24  X                                  widespread cloud
01:01:24  X                                  widespread cloud
01:16:24  NLC        3                       through cloud
01:31:24  NLC        3                       through cloud
01:45:47  X                                  almost overcast
02:00:47  X                                  overcast
02:16:30  X                                  overcast
02:30:32  X                                  overcast
02:45:19  X                                  overcast
03:00:08  X                                  overcast
03:15:06  X                                  almost overcast
03:30:05  X                                  almost 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: 2018/07/29-30
Start: 21:30
End: 01:30
Forms: II,IV
Max elevation: 40
Max brightness: 3
Comments: Increasing amount of cloud.
http://www.chiandh.eu/nlccam/20180729-30.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
21:30:05  0.500 320.0  -7.4   0.2 157.3  0-255 q3095.jpg m3095.jpg
21:45:09  2.000 323.3  -8.7  -1.0 115.4  0-255 q3097.jpg
22:00:19  4.000 326.8  -9.9  -1.9  38.8  0-255 q3100.jpg
22:15:32  8.000 330.2 -11.0  -2.6  18.8  0-255 q3104.jpg
22:30:53 15.000 333.8 -12.1  -3.2  11.9  0-255 q3110.jpg
22:46:25 30.000 337.5 -13.0  -3.8   8.5  0-255 q3116.jpg
23:01:24 30.000 341.0 -13.7  -4.2   6.4  0-255 q3122.jpg
23:16:24 30.000 344.6 -14.3  -4.6   5.1  0-255 q3128.jpg
23:31:24 30.000 348.3 -14.8  -4.8   4.2  0-255 q3134.jpg
23:46:24 30.000 351.9 -15.2  -5.0   3.6  0-255 q3140.jpg m3140.jpg
01:16:24 30.000  14.0 -14.5  -4.7   4.7  0-255 q3176.jpg m3176.jpg
01:31:24 30.000  17.6 -14.0  -4.4   5.8  0-255 q3182.jpg m3182.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).