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NLC 2011-06-27/28

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: 2011-06-27/28

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:45  X                                  overcast
22:00  X                                  overcast
22:15  X                                  overcast
22:30  X                                  overcast
22:45  X                                  overcast
23:00  X                                  overcast
23:15  X                                  overcast
23:30  X                                  overcast
23:45  X                                  overcast
00:00  X                                  almost overcast
00:15  X                                  cloud to h 25
00:30  X                                  cloud on right to h 20
00:45  X                                  cloud to h 10
01:00  II         1     8                 some cloud
01:15  II         1     8         5  >35
01:30  0?
01:45  II         1     9   8    15   22
02:00  0
02:15  0
02:30  0
02:45  0

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: 2011/06/27-28
Start: 01:00
End: 01:45
Forms: II
Max elevation: 9
Max brightness: 1
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2011-06-27/28">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
00:45  3.200   6.8 -10.5  -2.3  25.1  0-255 q14666.jpg m14666.jpg
01:00  2.500  10.3 -10.2  -2.1  30.9  0-255 q14669.jpg m14669.jpg
01:15  2.000  13.8  -9.8  -1.8  44.0  0-255 q14672.jpg m14672.jpg
01:30  1.000  17.2  -9.2  -1.4  76.4  0-255 q14674.jpg m14674.jpg
01:45  0.600  20.6  -8.5  -0.8 125.5  0-255 q14676.jpg m14676.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).