NLC 2019-06-16/17

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: 2019-06-16/17

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:45:01  X                                  almost overcast
22:00:06  X                                  almost overcast
22:15:08  X                                  overcast
22:30:08  X                                  almost overcast
22:45:10  X                                  overcast
23:00:11  X                                  almost overcast
23:15:19  X                                  overcast
23:30:31  X                                  almost overcast
23:45:32  X                                  widespread cloud
00:00:32  X                                  widespread cloud
00:15:19  II,IV      3    15       340       through cloud
00:30:19  II,IV      3             330       through cloud
00:45:18  I,IV       3    20                 through cloud
01:00:19  II,III     3    20            >35  through cloud
01:15:10  III,IV     2                       through cloud
01:30:09  II         2    20       330  >35  through cloud
01:45:02  II         2    35       330       cloud on right
02:00:02  II         1    20                 some cloud
02:15:02  II         1    13      <325       some cloud
02:30:01  0                                  cloud to h 3
02:45:01  X                                  some cloud patches

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: 2019-06-16/17
Start: 00:15
End: 02:15
Forms: I,II,III,IV
Max elevation: 35
Max brightness: 3
Comments: through cloud
http://www.chiandh.eu/nlccam/20190616-17.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
00:15:19  4.000   0.4 -10.7  -2.4  22.9  0-255 q7760.jpg
00:30:19  4.000   3.9 -10.6  -2.3  24.0  0-255 q7764.jpg
00:45:18  4.000   7.4 -10.4  -2.2  27.3  0-255 q7768.jpg
01:00:19  4.000  10.9 -10.1  -2.0  34.7  0-255 q7772.jpg
01:15:10  2.000  14.3  -9.6  -1.6  51.5  0-255 q7775.jpg
01:30:09  2.000  17.7  -9.0  -1.2  91.0  0-255 q7778.jpg
01:45:02  1.000  21.1  -8.3  -0.7 134.8  0-255 q7779.jpg
02:00:02  0.500  24.5  -7.5   0.1 155.5  0-255 q7781.jpg m7781.jpg
02:15:02  0.250  27.8  -6.6   1.2 164.9  0-255 q7783.jpg m7783.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).