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NLC 2009-07-24/25

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: 2009-07-24/25

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:15  X                                  cloud
21:30  X                                  cloud
21:45  X                                  cloud
22:00  X                                  cloud
22:15  X                                  cloud
22:30  X                                  cloud
22:45  X                                  cloud
23:00  X                                  cloud
23:15  X                                  cloud
23:30  X                                  cloud
23:45  X                                  cloud
00:00  X                                  cloud
00:15  X                                  cloud
00:30  X                                  cloud
00:45  X                                  cloud
01:00  NLC?                               through small cloud gap
01:15  X                                  cloud
01:30  NLC?                               through cloud gap
01:45  NLC?                               through cloud gaps
02:00  NLC?                               through cloud gaps
02:15  I,III      4     5                 cloud in front
02:30  NLC        3     5                 cloud on right
02:45  NLC        2     5                 cloud on right
03:00  0                                  low cloud on right
03:15  0                                  low cloud on right
03:30  0                                  low cloud on right

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: 2009/07/24-25
Start: 01:00
End: 02:45
Forms: I,III
Max elevation: 5
Max brightness: 4
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-24/25>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
----- ------ ----- ----- ----- -----  ----- ------------
01:00 25.000   9.9 -13.9  -4.3   5.9  0-150 q09515.jpg
01:30 25.000  17.1 -13.0  -3.8   8.5  0-200 q09545.jpg
01:45 25.000  20.6 -12.3  -3.4  10.9  0-255 q09560.jpg
02:00 25.000  24.1 -11.5  -2.9  15.3  0-255 q09575.jpg
02:15  8.000  27.6 -10.6  -2.3  24.6  0-255 q09590.jpg
02:30  4.000  31.0  -9.5  -1.6  55.6  0-255 q09600.jpg
02:45  2.500  34.4  -8.4  -0.7 132.3  0-255 q09606.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).