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NLC 2013-07-17/18

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: 2013-07-17/18

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:30:02  X                                  cloud to h 20
21:45:01  X                                  cloud to h 20
22:00:02  X                                  cloud to h 20, thin cloud above
22:15:08  X                                  cloud to h 20, thin cloud above
22:30:19  X                                  widespread cloud
22:45:31  X                                  widespread cloud
23:00:32  NLC?      2     10                 through cloud
23:15:33  I         3     10       -35   10  through cloud
23:30:54  I         3     10       -35   10  through cloud
23:45:47  I         2     10                 through cloud
00:00:47  X                                  cloud to h 10, thin cloud above
00:15:26  I         4      7       -10   15  through cloud
00:30:47  I         3      7       -10   15  through cloud
00:45:47  I         2      7       -20       through cloud
01:00:47  NLC       2                        through cloud
01:15:31  X                                  almost overcast
01:30:32  X                                  almost overcast
01:45:32  X                                  almost overcast
02:00:32  X                                  almost overcast
02:15:19  X                                  almost overcast
02:30:08  X                                  almost overcast
02:45:06  X                                  almost overcast
03:00:05  X                                  almost overcast
03:15:01  X                                  almost overcast

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: 2013/07/17-18
Start: 23:00
End: 01:00
Forms: I
Max elevation: 10
Max brightness: 4
Comments:
<a href="http://www.chiandh.me.uk/nlccam/20130717-18.shtml">Images</a>.
Through cloud.

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)
-------- ------ ----- ----- ----- -----  ----- -------------------
23:00:32  8.000 341.4 -11.3  -2.7  16.9  0-255 q6820.jpg m6820.jpg
23:15:33  8.000 344.9 -11.9  -3.1  12.9  0-255 q6825.jpg
23:30:54 15.000 348.5 -12.4  -3.4  10.5  0-255 q6832.jpg
23:45:47 15.000 352.1 -12.7  -3.6   9.2  0-255 q6837.jpg
00:15:26  8.000 359.2 -13.0  -3.8   8.2  0-255 q6848.jpg
00:30:47 15.000   2.8 -13.0  -3.8   8.3  0-255 q6855.jpg
00:45:47 15.000   6.4 -12.8  -3.7   8.8  0-255 q6861.jpg
01:00:47 15.000  10.0 -12.5  -3.5   9.9  0-255 q6867.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).