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NLC 2017-07-17/18

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: 2017-07-17/18

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:30:01  0                                  some cloud and haze
21:45:05  0                                  some cloud and haze
22:00:06  0                                  some cloud and haze
22:15:09  0                                  some cloud and haze
22:30:18  0                                  some cloud and haze
22:45:32  0                                  some cloud and haze
23:00:32  0                                  some cloud and haze
23:15:31  II          2    5       340   10  some cloud and haze
23:30:32  II          3    5       330    5  almost clear, haze on horizon
23:45:26  I,II        3    7       330    5  clear, haze on horizon
00:00:47  II,IV       3    7       325   35  clear
00:15:46  I,II        3    8      <325   35  clear
00:30:47  I,III,IV    3    8       330  >35  clear
00:45:47  I,III,IV    3    8       335  >35  clear
01:00:46  III,IV      3    7       345  >35  clear
01:15:53  I,IV        3   12       340  >35  clear
01:30:32  I,IV        3   14       340  >35  clear
01:45:33  I,III,IV    4   16       355  >35  almost clear
02:00:19  III,IV      3   20        10  >35  almost clear
02:15:10  IV          2   23         5   35  almost clear
02:30:01  I,III       1   15         5   25  almost clear
02:45:02  0                                  some cloud to h 5
03:00:01  0                                  some cloud to h 5
03:15:02  0                                  some 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: 2017/07/17-18
Start: 23:15
End: 02:30
Forms: I,II,III,IV
Max elevation: 23
Max brightness: 4
Comments: 
http://www.chiandh.eu/nlccam/20170717-18.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
23:15:31  8.000 344.9 -11.9  -3.1  12.8  0-255 q3146.jpg
23:30:32  8.000 348.4 -12.4  -3.4  10.6  0-255 q3152.jpg
23:45:26  8.000 352.0 -12.7  -3.6   9.2  0-255 q3157.jpg
00:00:47 15.000 355.6 -13.0  -3.8   8.5  0-255 q3164.jpg
00:15:46 15.000 359.2 -13.1  -3.8   8.2  0-255 q3170.jpg
00:30:47 15.000   2.8 -13.0  -3.8   8.3  0-255 q3176.jpg
00:45:47 15.000   6.4 -12.8  -3.7   8.8  0-255 q3182.jpg
01:00:46 15.000  10.0 -12.6  -3.5   9.8  0-255 q3188.jpg
01:15:53 15.000  13.6 -12.1  -3.3  11.6  0-255 q3195.jpg
01:30:32  8.000  17.0 -11.6  -2.9  14.6  0-255 q3200.jpg
01:45:33  8.000  20.5 -10.9  -2.5  20.2  0-255 q3205.jpg
02:00:19  4.000  23.9 -10.1  -2.0  33.2  0-255 q3209.jpg
02:15:10  2.000  27.3  -9.2  -1.4  76.1  0-255 q3212.jpg
02:30:01  0.500  30.7  -8.2  -0.5 139.6  0-255 q3214.jpg m3214.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).