chi and h site logo

NLC 2009-07-22/23

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: 2009-07-22/23

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:15  0                                  cloud to h 10
21:30  X                                  cloud to h 15
21:45  0                                  cloud patches
22:00  NLC?       1     5         5   20  cloud patches
22:15  NLC        2     5                 patchy cloud
22:30  NLC        2                       cloud in front and above
22:45  NLC                                cloud in front and above
23:00  NLC                                through narrow clear strip on horizon
23:15  NLC                                through narrow clear strip on horizon
23:30  NLC                                through narrow clear strip on horizon
23:45  X                                  cloud
00:00  X                                  cloud
00:15  X                                  cloud
00:30  X                                  cloud
00:45  X                                  cloud
01:00  X                                  cloud
01:15  X                                  cloud
01:30  X                                  cloud
01:45  X                                  cloud
02:00  X                                  cloud
02:15  X                                  cloud
02:30  X                                  cloud
02:45  X                                  cloud
03:00  X                                  cloud
03:15  X                                  cloud
03:30  X                                  cloud

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: 2009/07/22-23
Start: 22:00
End: 23:30
Forms: NLC
Max elevation: 5
Max brightness: 2
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2009-07-22/23>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)
----- ------ ----- ----- ----- -----  ----- ---------------------
22:00  2.500 327.2  -8.5  -0.8 129.2  0-255 q08821.jpg m08821.jpg
22:15  6.000 330.6  -9.6  -1.6  54.4  0-255 q08826.jpg
22:30 13.000 334.0 -10.5  -2.3  25.0  0-255 q08835.jpg
22:45 15.000 337.5 -11.4  -2.8  15.8  0-255 q08848.jpg
23:00 15.000 341.0 -12.2  -3.3  11.5  0-255 q08863.jpg
23:15 15.000 344.6 -12.8  -3.7   9.1  0-255 q08878.jpg
23:30 15.000 348.1 -13.3  -4.0   7.5  0-255 q08893.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).