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NLC 2012-07-27/28

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: 2012-07-27/28

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:00  0
21:15  0
21:30  0
21:45  0
22:00  0
22:15  0                                  cloud on right
22:30  0                                  cloud on right to h 5
22:45  0
23:00  0
23:15  NLC?                               through cloud
23:30  NLC?                               through cloud
23:45  NLC?                               through cloud
00:00  NLC        1                       through cloud
00:15  X                                  cloud to h 5
00:30  I          2                       through cloud
00:45  X                                  cloud to h 5 or 10
01:00  NLC?                               through cloud
01:15  NLC        2                       through cloud
01:30  NLC                                through cloud
01:45  NLC                                through cloud
02:00  X                                  cloud to h 10 or 20
02:15  X                                  cloud to h 10 or 20
02:30  X                                  cloud to h 20 or 25
02:45  X                                  widespread cloud
03:00  X                                  cloud to h 15 or 25
03:15  X                                  cloud to h 20
03:30  X                                  cloud to h 20

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: 2012/07/27-28
Start: 23:15
End: 01:45
Forms: O
Max elevation:  5
Max brightness: 2
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2012-07-27/28">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
23:15 15.000 344.4 -13.9  -4.3   6.0  0-255 q02742.jpg m02742.jpg
23:30 15.000 348.0 -14.4  -4.6   4.9  0-255 q02748.jpg m02748.jpg
23:45 15.000 351.6 -14.8  -4.8   4.3  0-255 q02754.jpg m02754.jpg
00:00 15.000 355.3 -15.0  -5.0   3.9  0-255 q02760.jpg m02760.jpg
00:30 15.000   2.6 -15.1  -5.0   3.7  0-255 q02772.jpg
01:00 15.000  10.0 -14.7  -4.7   4.5  0-255 q02784.jpg m02784.jpg
01:15  8.000  13.6 -14.2  -4.5   5.3  0-255 q02789.jpg
01:30 15.000  17.2 -13.7  -4.2   6.5  0-255 q02796.jpg
01:45 15.000  20.8 -13.0  -3.8   8.3  0-255 q02802.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).