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NLC 2011-07-07/08

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 15 min
Date: 2011-07-07/08

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:45  0                                  some cloud patches
22:00  X                                  patchy cloud
22:15  II          2  >35      <325  >35  through cloud
22:30  II,III      2  >35      <325  >35  through cloud
22:45  II,III      2  >35      <325  >35  through cloud
23:00  II,III      3                      through cloud
23:15  II          3                      through cloud
23:30  NLC         3                      through cloud
23:45  X                                  almost overcast
00:00  X                                  almost overcast
00:15  X                                  almost overcast
00:30  NLC         2                      almost overcast
00:45  X                                  almost overcast
01:00  NLC         3                      almost overcast
01:15  X                                  almost overcast
01:30  X                                  almost overcast
01:45  X                                  overcast
02:00  X                                  overcast
02:15  X                                  overcast
02:30  X                                  overcast
02:45  X                                  almost overcast
03:00  X                                  patchy 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: 2011/07/07-08
Start: 22:15
End: 23:30
Forms: II,III
Max elevation: >35
Max brightness: 3
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2011-07-07/08">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      (masked)
----- ------ ----- ----- ----- -----  ----- ---------------------
22:15  0.250 331.6  -7.3   0.3 158.3  0-255 q15237.jpg
22:30  0.500 335.0  -8.3  -0.6 137.7  0-255 q15239.jpg
22:45  1.000 338.4  -9.1  -1.3  85.8  0-255 q15241.jpg
23:00  2.000 341.8  -9.8  -1.8  42.7  0-255 q15244.jpg
23:15  3.200 345.3 -10.4  -2.2  27.1  0-255 q15248.jpg
23:30  5.000 348.8 -10.9  -2.5  20.4  0-255 q15252.jpg
00:30  8.000   2.9 -11.5  -2.9  15.1  0-255 q15272.jpg
01:00  5.000   9.9 -11.0  -2.6  18.9  0-255 q15281.jpg

exp: Exposure time in seconds (400 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).