chi and h site logo

NLC 2015-07-21/22

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: 2015-07-21/22

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:04  X                                  overcast
21:30:01  X                                  widespread cloud
21:45:01  0                                  cloud to h 5
22:00:02  0                                  cloud to h 5
22:15:10  0                                  cloud to h 5
22:30:31  0                                  patchy cloud to h 10
22:45:32  I          1     5                 through cloud
23:00:54  I          3     8       350  >35
23:15:47  I          3                       through cloud
23:30:47  I          3                       through cloud
23:45:47  X                                  almost overcast
00:00:47  I          2                       through cloud
00:16:25  I          3     7       325  >35
00:31:24  I,II       4     7       330  >35
00:45:47  I,II       5     7       330  >35
01:00:26  I,III      5     8       335  >35
01:15:26  I,III      5     9       335  >35
01:30:32  I,III      5    11       335  >35
01:45:19  III,IV     5    14       330  >35
02:00:19  I.II       4    15                 some cloud patches
02:15:10  II,III     3    15                 some cloud patches
02:30:03  I          2    12      <325   10
02:45:06  I          1     5      <325  350
03:00:04  X                                  some cloud
03:15:01  X                                  some 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: 2015/07/21-22
Start: 22:45
End: 02:45
Forms: I,II,III,IV
Max elevation: 15
Max brightness: 5
Comments: Some cloud patches.
http://www.chiandh.eu/nlccam/20150721-22.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)
-------- ------ ----- ----- ----- -----  ----- -------------------
22:45:32  8.000 337.7 -11.2  -2.7  17.8  0-255 q5165.jpg
23:00:54 15.000 341.3 -11.9  -3.1  12.7  0-255 q5171.jpg
23:15:47 15.000 344.8 -12.5  -3.5  10.0  0-255 q5176.jpg
23:30:47 15.000 348.4 -13.0  -3.8   8.3  0-255 q5182.jpg
00:00:47 15.000 355.6 -13.6  -4.1   6.7  0-255 q5194.jpg
00:16:25 30.000 359.3 -13.7  -4.2   6.5  0-255 q5201.jpg
00:31:24 30.000   2.9 -13.7  -4.2   6.5  0-255 q5207.jpg
00:45:47 15.000   6.4 -13.5  -4.1   6.9  0-255 q5212.jpg
01:00:26  8.000   9.9 -13.2  -3.9   7.7  0-255 q5217.jpg
01:15:26  8.000  13.5 -12.8  -3.7   9.0  0-255 q5223.jpg
01:30:32  8.000  17.1 -12.2  -3.3  11.1  0-255 q5230.jpg
01:45:19  4.000  20.6 -11.6  -2.9  14.7  0-255 q5235.jpg
02:00:19  4.000  24.1 -10.8  -2.4  21.8  0-255 q5241.jpg
02:15:10  2.000  27.5  -9.9  -1.8  41.0  0-255 q5245.jpg
02:30:03  1.000  30.9  -8.9  -1.1 105.7  0-255 q5247.jpg
02:45:06  1.000  34.2  -7.7  -0.1 152.3  0-255 q5250.jpg m5250.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).