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NLC 2009-07-04/05

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: 2009-07-04/05

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  -------  ---- ----  --------------------------------
21:45  X                                  cloud to h 25
22:00  X                                  cloud to h 25
22:15  X                                  cloud to h 20
22:30  X                                  cloud
22:45  X                                  cloud
23:00  I          1    15                 cloud to h 15
23:15  X                                  patchy cloud
23:30  X                                  cloud to h 25
23:45  I,II       2    15      <325  >10  cloud on right to h 15
00:00  I,II       2    15   0  <325  >10  cloud on right to h 10
00:15  II,IV      3    15   0  <325   25  cloud on right to h 5
00:30  II,IV      3    15   0  <325  >30  clear
00:45  II,IV      3    15   0  <325  >35  clear
01:00  II,IV      3    15   0  <325  >10  clear
01:15  II,IV      3    20   0  <325  >15  cloud on right to h 10
01:30  IV         3    25   5  <325  >20  cloud on right to h 15
01:45  III        3    25  10  <325   20  clear
02:00  III        3    25  15  <325   15  almost clear
02:15  III,IV     2    30  10  <325   15  almost clear
02:30  NLC?       1                       almost clear
02:45  0                                  almost clear
03:00  X                                  cirrus

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: 2009/07/04-05
Start: 23:00
End: 02:30
Forms: II,III,IV
Max elevation: 30
Max brightness: 3
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-04/05>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
----- ------ ----- ----- ----- -----  ----- ------------
23:00  6.000 342.0  -9.6  -1.6  53.0  0-255 q05008.jpg
23:45  8.000 352.4 -11.0  -2.6  19.4  0-200 q05040.jpg
00:00  8.000 355.9 -11.2  -2.7  17.4  0-200 q05053.jpg
00:15 15.000 359.5 -11.3  -2.8  16.7  0-255 q05067.jpg
00:30  8.000   3.0 -11.2  -2.7  17.1  0-200 q05083.jpg
00:45  8.000   6.5 -11.1  -2.6  18.6  0-200 q05096.jpg
01:00  8.000  10.0 -10.8  -2.4  21.8  0-255 q05108.jpg
01:15  4.000  13.5 -10.3  -2.1  28.5  0-200 q05120.jpg
01:30  4.000  17.0  -9.8  -1.8  43.8  0-255 q05129.jpg
01:45  2.000  20.4  -9.1  -1.3  84.7  0-255 q05137.jpg
02:00  2.000  23.8  -8.3  -0.6 135.6  0-255 q05141.jpg
02:15  1.000  27.2  -7.4   0.2 157.0  0-255 q05144.jpg
02:30  0.400  30.5  -6.4   1.5 166.1  0-255 q05147.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).