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NLC 2009-07-20/21

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: 2009-07-20/21

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  -------  ---- ----  --------------------------------
21:15  X                                  cloud to h 15 and top left
21:30  X                                  cloud
21:45  X                                  cloud
22:00  X                                  patchy cloud, probably no NLC
22:15  X                                  patchy cloud, probably no NLC
22:30  0                                  cloud to h 5
22:45  0                                  cloud to h 5
23:00  0                                  cloud to h 5
23:15  0                                  cloud to h 5, and above h 20
23:30  0                                  cloud to h 5, some patches above
23:45  X                                  cloud, probably no NLC
00:00  X                                  cloud
00:15  X                                  cloud
00:30  NLC?       1     5       350   10  patchy cloud
00:45  NLC        1     5       350   10  patchy cloud
01:00  NLC        1     5       350   10  patchy cloud
01:15  X                                  cloud above h 5
01:30  X                                  cloud above h 5
01:45  X                                  cloud
02:00  X                                  cloud
02:15  X                                  cloud
02:30  X                                  cloud
02:45  X                                  cloud to h 20
03:00  X                                  cloud to h 15
03:15  X                                  cloud to h 10

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: 2009/07/20-21
Start: 00:30
End: 01:00
Forms: NLC
Max elevation: 5
Max brightness: 1
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-20/21>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)
----- ------ ----- ----- ----- -----  ----- ---------------------
00:30 25.000   2.6 -13.6  -4.1   6.8  0-255 q08433.jpg m08433.jpg
00:45 25.000   6.2 -13.4  -4.0   7.2  0-255 q08448.jpg m08448.jpg
01:00 25.000   9.8 -13.1  -3.9   8.0  0-255 q08463.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).