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NLC 2019-05-24/25

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: 2019-05-24/25

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:01  X                                  widespread cloud
21:30:01  X                                  cloud to h 20
21:45:06  X                                  widespread cloud
22:00:03  X                                  widespread cloud
22:15:09  X                                  widespread cloud
22:30:19  X                                  patchy cloud
22:45:19  X                                  patchy cloud
23:00:32  I          1    10                 cloud to h 5 or 10
23:15:33  II         1    10                 some cloud to h 10
23:30:47  II         1     8                 some cloud to h 10
23:45:47  II         1                       through cloud
00:00:47  II         2     8                 some cloud to h 10
00:15:47  II         2                       some cloud to h 10
00:30:47  II         2                       through cloud
00:45:47  II         2                       through cloud
01:00:53  II         2                       through cloud
01:15:54  II         2                       through cloud
01:30:33  II         2                       through cloud
01:45:32  NLC?                               through cloud
02:00:19  X                                  widespread cloud
02:15:09  X                                  widespread cloud
02:30:01  X                                  almost overcast
02:45:05  X                                  almost overcast
03:00:05  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: 2019-05-24/25
Start: 23:00
End: 01:45
Forms: I,II
Max elevation: 10
Max brightness: 2
Comments: through cloud
http://www.chiandh.eu/nlccam/20190524-25.html

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)
-------- ------ ----- ----- ----- -----  ----- -------------------
23:00:32  8.000 343.5 -11.8  -3.1  13.2  0-255 q5998.jpg m5998.jpg
23:15:33  8.000 347.0 -12.3  -3.4  10.7  0-255 q6004.jpg m6004.jpg
23:30:47 15.000 350.7 -12.8  -3.7   9.1  0-255 q6010.jpg m6010.jpg
23:45:47 15.000 354.3 -13.0  -3.8   8.2  0-255 q6016.jpg m6016.jpg
00:00:47 15.000 357.8 -13.2  -3.9   7.8  0-255 q6022.jpg m6022.jpg
00:15:47 15.000   1.4 -13.2  -3.9   7.8  0-255 q6028.jpg m6028.jpg
00:30:47 15.000   5.0 -13.1  -3.8   8.1  0-255 q6034.jpg m6034.jpg
00:45:47 15.000   8.6 -12.8  -3.7   8.9  0-255 q6040.jpg
01:00:53 15.000  12.2 -12.4  -3.5  10.3  0-255 q6047.jpg
01:15:54 15.000  15.8 -11.9  -3.1  12.6  0-255 q6053.jpg
01:30:33  8.000  19.2 -11.3  -2.8  16.6  0-255 q6058.jpg m6058.jpg
01:45:32  8.000  22.7 -10.5  -2.3  24.9  0-255 q6063.jpg m6063.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).