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NLC 2019-07-15/16

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: 2019-07-15/16

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:30:04  X                                  haze to h 30
21:45:05  X                                  haze to h 30
22:00:05  X                                  haze to h 30
22:15:08  X                                  haze to h 30
22:30:19  X                                  haze and thin cloud
22:45:32  X                                  haze and thin cloud
23:00:53  X                                  haze and thin cloud
23:15:53  X                                  haze and thin cloud
23:31:30  X                                  haze and thin cloud
23:46:31  X                                  haze and thin cloud
00:01:24  X                                  haze and thin cloud
00:16:24  X                                  haze and thin cloud
00:31:24  NLC        2                       through thick haze
00:46:24  II         2                       through thick haze
01:01:31  II         2                       through thick haze
01:16:31  II         2                       through thick haze
01:30:53  II         3    13                 thick haze below
01:45:31  II         3    13                 thick haze below
02:00:09  II,IV      2    14                 through cloud
02:15:09  NLC                                through cloud
02:30:06  X                                  cloud and haze to h 30
02:45:05  X                                  cloud and haze to h 30
03:00:05  X                                  cloud and haze to h 30
03:15:04  X                                  cloud and haze to h 30

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: 2019-07-15/16
Start: 00:30
End: 02:15
Forms: II,IV
Max elevation: 14
Max brightness: 3
Comments: through cloud
http://www.chiandh.eu/nlccam/20190715-16.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
00:31:24 30.000   3.0 -12.6  -3.5   9.8  0-255 q9754.jpg
00:46:24 30.000   6.5 -12.4  -3.4  10.4  0-255 q9760.jpg
01:01:31 30.000  10.1 -12.1  -3.3  11.8  0-255 q9767.jpg
01:16:31 30.000  13.7 -11.7  -3.0  14.1  0-255 q9773.jpg
01:30:53 15.000  17.0 -11.1  -2.7  18.0  0-255 q9778.jpg
01:45:31  8.000  20.4 -10.5  -2.2  26.1  0-255 q9782.jpg
02:00:09  2.000  23.8  -9.7  -1.7  47.4  0-255 q9784.jpg
02:15:09  2.000  27.2  -8.8  -1.0 109.3  0-255 q9787.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).