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NLC 2013-07-30/31

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: 2013-07-30/31

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:00:01  X                                  widespread cloud
21:15:01  X                                  widespread cloud
21:30:02  X                                  widespread cloud
21:45:03  X                                  widespread cloud
22:00:33  0                                  cloud to h 10
22:15:32  X                                  almost overcast
22:30:52  X                                  cloud to h 10, some higher
22:45:47  X                                  widespread cloud
23:01:24  X                                  cloud to h 5
23:16:24  X                                  cloud on horizon
23:31:24  X                                  cloud on horizon
23:46:24  X                                  cloud on horizon
00:01:24  X                                  cloud on horizon
00:16:24  X                                  cloud on horizon
00:30:47  X                                  cloud on horizon
00:46:24  NLC        2     5        15   35  through cloud
01:01:24  I,II       3     5        10  >35  cloud to the left
01:15:47  I,II       3     5        -5  >35  through cloud
01:30:26  I,III      3     5       -10  >35
01:45:25  I,III      4     8       -20  >35
02:00:13  I,II       5     9       -20  >35
02:15:19  I,II       5     9       -25  >35
02:30:10  I,IV       5    12       -30  >35
02:45:10  IV         3    12       -35  >35
03:00:03  II         2    12       -30   30
03:15:02  0
03:30:01  0
03:45:01  0

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: 2013/07/30-31
Start: 00:45
End: 03:00
Forms: I,II,III,IV
Max elevation: 12
Max brightness: 5
Comments:
<a href="http://www.chiandh.me.uk/nlccam/20130730-31.shtml">Images</a>.

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)
-------- ------ ----- ----- ----- -----  ----- -------------------
00:46:24 30.000   6.7 -15.6  -5.3   3.0  0-255 q8334.jpg m8334.jpg
01:01:24 30.000  10.4 -15.3  -5.1   3.5  0-255 q8340.jpg
01:15:47 15.000  13.9 -14.9  -4.9   4.1  0-255 q8345.jpg m8345.jpg
01:30:26  8.000  17.5 -14.3  -4.5   5.2  0-255 q8350.jpg
01:45:25  8.000  21.1 -13.6  -4.2   6.7  0-255 q8356.jpg
02:00:13  4.000  24.6 -12.8  -3.7   8.9  0-255 q8361.jpg
02:15:19  4.000  28.1 -11.9  -3.1  12.9  0-255 q8368.jpg
02:30:10  2.000  31.5 -10.8  -2.5  20.9  0-255 q8373.jpg
02:45:10  2.000  35.0  -9.7  -1.7  47.9  0-255 q8378.jpg
03:00:03  1.000  38.3  -8.5  -0.7 130.2  0-255 q8380.jpg m8380.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).