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NLC 2009-07-30/31

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: 2009-07-30/31

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:00  0
21:15  0
21:30  0                                  aeroplane
21:45  0                                  some cirrus
22:00  0                                  some cirrus
22:15  0                                  some cirrus, aeroplane
22:30  II         2     5       355   15  cirrus above
22:45  II         2     5       350   20  some cirrus above
23:00  II         2     5       345   15
23:15  NLC        2     5       345   10
23:30  NLC        2     5       340   10
23:45  NLC        2     5       345   15
00:00  NLC        2     5       350   10
00:15  NLC        2     5       350   20
00:30  NLC        2     5       345   25
00:45  NLC        2     5       345   25
01:00  I,III      3     5       345   20
01:15  NLC        3     5       350   15
01:30  NLC        3     5                 behind cirrus
01:45  NLC        4     5       355  >35  some cirrus in front
02:00  NLC        4    10       355  >35  cirrus above
02:15  NLC        4    10       355  >35  cirrus above, some in front
02:30  NLC        3    10                 cirrus in front
02:45  NLC        3    15                 cirrus in front
03:00  X                                  cirrus
03:15  0                                  cirrus
03:30  0                                  cirrus
03:45  0                                  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: 2009/07/30-31
Start: 22:30
End: 02:45
Forms: I,II,III,O
Max elevation: 15
Max brightness: 4
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-30/31>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
----- ------ ----- ----- ----- -----  ----- ------------
22:30 25.000 333.5 -12.3  -3.4  10.9  0-200 q11128.jpg
22:45 25.000 337.1 -13.2  -3.9   7.8  0-200 q11143.jpg
23:00 25.000 340.7 -13.9  -4.3   5.9  0-255 q11158.jpg
23:15 25.000 344.3 -14.6  -4.7   4.7  0-255 q11173.jpg
23:30 25.000 347.9 -15.1  -5.0   3.8  0-255 q11188.jpg
23:45 25.000 351.6 -15.4  -5.2   3.2  0-255 q11203.jpg
00:00 25.000 355.3 -15.7  -5.3   2.9  0-200 q11218.jpg
00:15 25.000 359.0 -15.8  -5.4   2.7  0-200 q11233.jpg
00:30 25.000   2.7 -15.8  -5.4   2.7  0-150 q11248.jpg
00:45 25.000   6.4 -15.6  -5.3   3.0  0-150 q11263.jpg
01:00 25.000  10.0 -15.3  -5.1   3.4  0-255 q11278.jpg
01:15 15.000  13.7 -14.9  -4.9   4.1  0-255 q11294.jpg
01:30 15.000  17.3 -14.3  -4.6   5.1  0-255 q11309.jpg
01:45 15.000  20.9 -13.6  -4.2   6.6  0-255 q11324.jpg
02:00 15.000  24.5 -12.8  -3.7   8.9  0-255 q11339.jpg
02:15 15.000  28.0 -11.9  -3.1  12.8  0-255 q11354.jpg
02:30 15.000  31.5 -10.9  -2.5  20.8  0-255 q11368.jpg
02:45  6.000  34.9  -9.7  -1.7  47.5  0-255 q11379.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).