NLC 2019-05-22/23

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: 2019-05-22/23

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:01  0                                  cloud to h 5
21:30:05  0                                  cloud to h 5
21:45:06  0                                  cloud to h 5
22:00:09  0                                  cloud to h 5
22:15:19  0                                  cloud to h 5
22:30:32  0                                  cloud to h 5
22:45:53  X                                  cloud to h 8
23:01:31  X                                  cloud to h 10
23:17:33  X                                  cloud to h 10
23:32:33  X                                  cloud to h 10
23:47:33  X                                  cloud to h 10
00:02:33  X                                  cloud to h 10
00:17:33  X                                  cloud to h 10
00:32:34  X                                  cloud to h 10
00:47:34  X                                  cloud to h 10
01:02:33  X                                  cloud to h 10
01:16:31  NLC        1    12                 cloud to h 10
01:31:30  IV         2    12       345       cloud to h 10 on right
01:45:53  IV         2    10       335   10  cloud to h 7 on right
02:00:19  IV         2    15       330   35  cloud to h 5
02:15:09  I          1    20       335   35  cloud to h 5
02:30:06  0                                  cloud to h 5
02:45:06  0                                  cloud to h 5
03:00:05  0                                  cloud to h 5
03:15:04  0                                  cloud to h 5

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: 2019-05-22-23
Start: 01:15
End: 02:15
Forms: I,IV
Max elevation: 20
Max brightness: 2
Comments: cloud to h 5 or 10
http://www.chiandh.eu/nlccam/20190522-23.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
01:16:31 30.000  16.0 -12.3  -3.4  11.0  0-255 q5850.jpg m5850.jpg
01:31:30 30.000  19.5 -11.6  -3.0  14.4  0-255 q5856.jpg
01:45:53 15.000  22.9 -10.9  -2.5  20.5  0-255 q5861.jpg
02:00:19  4.000  26.2 -10.0  -1.9  35.5  0-255 q5864.jpg
02:15:09  2.000  29.6  -9.1  -1.2  88.9  0-255 q5866.jpg m5866.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).