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NLC 2009-07-12/13

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 dSLR with limited field of view A ~325-35, h ~0-40
          images every 5 min
Date: 2009-07-12/13

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  -------  ---- ----  --------------------------------
21:30  X                                  patchy cirrus
21:45  X                                  cirrus
22:00  I,III      2    40                 cloud below and on right
22:15  NLC        3                       through cloud gap
22:30  II         3                       cloud above
22:45  II         3                       cloud above
23:00  NLC        3                       through cloud
23:15  NLC        4                       through cloud
23:30  NLC        4                       through cloud
23:45  NLC        4                       cloud above
00:00  NLC        4                       cloud above
00:15  NLC        4                       cloud above
00:30  NLC        4                       cloud above
00:45  NLC        4                       cloud above
01:00  NLC        4                       through cloud
01:15  NLC        4                       through cloud
01:30  NLC        4                       through cloud
01:45  NLC        3                       through cloud
02:00  X                                  cloud
02:15  X                                  cloud
02:30  X                                  cloud
02:45  X                                  cloud
03:00  X                                  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: 2009/07/12-13
Start: 22:00
End: 01:45
Forms: I,II,III
Max elevation: 40
Max brightness: 4
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-12/13>Images</a>.

forms: I: veil
       II: bands
       III: waves
       IV: whirls
       O: 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
----- ------ ----- ----- ----- -----  ----- ------------
22:00  0.600 327.9  -6.9   0.9 162.8  0-255 q06490.jpg
22:15  1.300 331.3  -7.9  -0.3 147.6  0-255 q06493.jpg
22:30  2.000 334.6  -8.9  -1.1 102.0  0-255 q06497.jpg
22:45  4.000 338.1  -9.7  -1.7  45.7  0-255 q06504.jpg
23:00  8.000 341.5 -10.5  -2.2  26.1  0-255 q06513.jpg
23:15  8.000 345.0 -11.1  -2.6  18.5  0-255 q06525.jpg
23:30  8.000 348.5 -11.6  -2.9  14.7  0-255 q06540.jpg
23:45 15.000 352.1 -11.9  -3.1  12.6  0-255 q06554.jpg
00:00 15.000 355.6 -12.1  -3.3  11.5  0-255 q06569.jpg
00:15 15.000 359.2 -12.2  -3.3  11.1  0-255 q06584.jpg
00:30 15.000   2.7 -12.2  -3.3  11.2  0-255 q06599.jpg
00:45  8.000   6.3 -12.0  -3.2  12.0  0-255 q06615.jpg
01:00  8.000   9.8 -11.7  -3.0  13.6  0-255 q06630.jpg
01:15  8.000  13.4 -11.3  -2.8  16.4  0-255 q06645.jpg
01:30  8.000  16.9 -10.8  -2.4  21.7  0-255 q06657.jpg
01:45 10.000  20.3 -10.1  -2.0  33.6  0-255 q06667.jpg

exp: Exposure time in seconds (200 ISO, f/3.5).
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).