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NLC 2017-07-18/19

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: 2017-07-18/19

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:30:01  0                                  clear
21:45:05  0                                  clear
22:00:06  0                                  thin cloud to h 5
22:15:10  0                                  thin cloud to h 5
22:30:19  0                                  thin cloud to h 5
22:45:31  I           1    8         0   30  thin cloud to h 5 or 10
23:00:32  IV          2    7                 haze to h 5
23:15:32  IV          2    7       330   30  haze to h 3
23:30:47  I,IV        2    7       330   30  clear
23:45:47  I,IV        2    7       330   30  clear
00:00:46  I,IV        2    7       325   30  clear
00:15:47  I,IV        2    7       325   35  clear
00:30:46  I,IV        2    7       325   35  clear
00:45:47  I,IV        2    5       330   25  clear
01:00:47  I,IV        2    8       325   25  clear
01:15:53  I           2    8       335   10  almost clear
01:30:54  I           2    6       335    0  almost clear
01:45:32  I           2    6       340  355  almost clear
02:00:19  X                                  haze on horizon
02:15:09  X                                  cloud patches
02:30:02  X                                  cloud patches
02:45:05  X                                  widepread cloud
03:00:05  X                                  widepread cloud
03:15:05  X                                  widepread cloud

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: 2017/07/18-19
Start: 22:45
End: 01:45
Forms: I,IV
Max elevation: 8
Max brightness: 2
Comments: 
http://www.chiandh.eu/nlccam/20170718-19.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
22:45:31  8.000 337.8 -10.7  -2.4  22.6  0-255 q3236.jpg m3236.jpg
23:00:32  8.000 341.3 -11.4  -2.9  15.5  0-255 q3240.jpg
23:15:32  8.000 344.8 -12.1  -3.2  11.9  0-255 q3245.jpg
23:30:47 15.000 348.5 -12.5  -3.5   9.9  0-255 q3251.jpg
23:45:47 15.000 352.0 -12.9  -3.7   8.6  0-255 q3257.jpg
00:00:46 15.000 355.6 -13.1  -3.9   7.9  0-255 q3263.jpg
00:15:47 15.000 359.2 -13.2  -3.9   7.7  0-255 q3269.jpg
00:30:46 15.000   2.8 -13.2  -3.9   7.8  0-255 q3275.jpg
00:45:47 15.000   6.4 -13.0  -3.8   8.2  0-255 q3281.jpg
01:00:47 15.000  10.0 -12.7  -3.6   9.2  0-255 q3287.jpg
01:15:53 15.000  13.6 -12.3  -3.4  10.8  0-255 q3294.jpg
01:30:54 15.000  17.1 -11.7  -3.0  13.6  0-255 q3300.jpg
01:45:32  8.000  20.5 -11.1  -2.6  18.4  0-255 q3305.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).