chi and h site logo

NLC 2013-07-20/21

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 compact camera with limited field of view
          A ~325-35, h ~0-40; images every 15 min
Date: 2013-07-20/21

   UT     forms  bright   height   azimuth   comments
                  ness   top bot  left rght  e.g. weather
--------  -----  ------  --- ---  ---- ----  --------------------------------
21:15:01  X                                  widespread cirrus
21:30:01  X                                  cirrus to h 15 or 20
21:45:06  X                                  cirrus dark to h 20, bright above
22:00:02  X                                  cirrus dark to h 20, bright above
22:15:10  I          1    17                 through cloud
22:30:19  I          1    15                 through cloud
22:45:32  III        3    12                 through cloud
23:00:32  NLC        1                       through cloud
23:15:53  X                                  cloud to h 10
23:30:47  X                                  widepsread cloud
23:45:47  X                                  cloud to h 15
00:00:47  X                                  cloud and haze
00:15:47  X                                  cloud and haze
00:30:46  X                                  overcast
00:45:26  X                                  overcast
01:00:26  X                                  overcast
01:15:25  X                                  overcast
01:30:32  X                                  overcast
01:45:32  X                                  overcast
02:00:33  X                                  overcast
02:15:19  X                                  overcast
02:30:10  X                                  overcast
02:45:08  X                                  overcast
03:00:02  X                                  overcast
03:15:02  X                                  overcast

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: 2013/07/20-21
Start: 22:15
End: 23:00
Forms: I,III
Max elevation: 17
Max brightness: 3
Comments:
<a href="http://www.chiandh.me.uk/nlccam/20130720-21.shtml">Images</a>.
Through cloud.

forms: I: veil
       II: bands
       III: waves
       IV: whirls
       NLC: 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)
-------- ------ ----- ----- ----- -----  ----- -------------------
22:15:10  2.000 330.7  -9.2  -1.3  77.9  0-255 q7113.jpg m7113.jpg
22:30:19  4.000 334.2 -10.2  -2.0  31.7  0-255 q7116.jpg m7116.jpg
22:45:32  8.000 337.7 -11.1  -2.6  18.7  0-255 q7121.jpg
23:00:32  8.000 341.2 -11.8  -3.1  13.3  0-255 q7126.jpg

exp: Exposure time in seconds (200 ISO, f/2.8).
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).