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NLC 2009-07-15/16

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: 2009-07-15/16

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  -------  ---- ----  --------------------------------
21:30  0                                  cloud to h 10
21:45  II         1    10        15   30  cloud patches to h 5
22:00  II         2    10   5     5  >35  clear
22:15  III        2    10   0     0   30  clear
22:30  III        2    10   0   355   25  clear
22:45  IV         2    15   5   350    5  clear
23:00  I,II       1    10   0   350   30  clear
23:15  II         2     5   0     5   30  among some low cloud
23:30  NLC        2     5   0     5   25  among some low cloud
23:45  NLC        2     5   0     5   30  among some low cloud, aeroplane trail
00:00  III        2     5   0     5  >35  among cloud
00:15  III        2     5   0             cloud nearby, aeroplane trail
00:30  III        2     5                 some cloud on horizon
00:45  III        3     5        15  >35  some cloud on horizon
01:00  III        3     5        15  >35  clear
01:15  III        2    10   0    15  >35  clear, few cloud patches
01:30  0                                  few cloud patches
01:45  NLC        2   on horiz  355    5  some cloud
02:00  NLC?           on horiz  340  355  cloud above h 5
02:15  NLC?           on horiz  345  355  cloud above h 5
02:30  X                                  cloud above h 5
02:45  X                                  cloud above h 5
03:00  X                                  cloud above h 5
03:15  X                                  cloud above h 5

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: 2009/07/15-16
Start: 21:45
End: 01:15
Forms: O
Max elevation: 10
Max brightness: 3
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-15/16>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
----- ------ ----- ----- ----- -----  ----- ------------
21:45  0.300 324.4  -6.1   2.0 167.7  0-255 q07138.jpg
22:00  0.800 327.7  -7.3   0.4 158.7  0-255 q07141.jpg
22:15  2.000 331.1  -8.4  -0.7 134.2  0-255 q07144.jpg
22:30  5.000 334.5  -9.3  -1.4  69.0  0-255 q07149.jpg
22:45 10.000 337.9 -10.2  -2.0  32.0  0-255 q07157.jpg
23:00 20.000 341.4 -10.9  -2.5  20.2  0-255 q07168.jpg
23:15 15.000 344.9 -11.5  -2.9  15.0  0-255 q07182.jpg
23:30 15.000 348.4 -12.0  -3.2  12.2  0-255 q07197.jpg
23:45 25.000 352.0 -12.4  -3.4  10.6  0-255 q07211.jpg
00:00 25.000 355.5 -12.6  -3.6   9.7  0-255 q07226.jpg
00:15 25.000 359.1 -12.7  -3.6   9.3  0-255 q07241.jpg
00:30 25.000   2.7 -12.7  -3.6   9.4  0-255 q07256.jpg
00:45 15.000   6.2 -12.5  -3.5  10.0  0-255 q07272.jpg
01:00 25.000   9.8 -12.2  -3.3  11.2  0-255 q07286.jpg
01:15 15.000  13.4 -11.8  -3.1  13.3  0-255 q07302.jpg
01:45  8.000  20.4 -10.6  -2.3  24.4  0-255 q07330.jpg
02:00  4.000  23.8  -9.8  -1.8  43.8  0-255 q07340.jpg
02:15  2.000  27.2  -8.9  -1.1 103.0  0-255 q07348.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).