NLC 2012-07-26/27

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 15 min
Date: 2012-07-26/27

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:15  0
21:30  0
21:45  0
22:00  0
22:15  0
22:30  0
22:45  0
23:00  0
23:15  0
23:30  0
23:45  0
00:00  0
00:15  0
00:30  0
00:45  0
01:00  I          1     5
01:15  I          1     8       350  >35
01:30  I,III      2     8       350  >35
01:45  III,IV     3    10       350  >35
02:00  III,IV     4    12       345  >35
02:15  I,IV       5    12       345  >35
02:30  II,IV      4    12       350  >35
02:45  IV         4    15            >35  cloud to h 10 and on left
03:00  II         4                       widespread cloud
03:15  X                                  almost overcast
03:30  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 main periods of absence of NLC are reported to the NLC Observers' Home Page:

Name: Horst Meyerdierks
Country: Scotland
Location: Edinburgh
Date: 2012/07/26-27
Start: 21:15
End: 00:45
Comments:

The main periods of positive sightings of NLC are reported to the NLC Observers' Home Page:

Name: Horst Meyerdierks
Country: Scotland
Location: Edinburgh
Date: 2012/07/26-27
Start: 01:00
End: 03:00
Forms: I,II,III,IV
Max elevation:  15
Max brightness: 5
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2012-07-26/27">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
01:00 30.000   9.9 -14.4  -4.6   4.9  0-255 q02667.jpg m02667.jpg
01:15 30.000  13.6 -14.0  -4.4   5.8  0-255 q02673.jpg
01:30 15.000  17.2 -13.4  -4.1   7.1  0-255 q02678.jpg
01:45 15.000  20.7 -12.8  -3.7   9.1  0-255 q02684.jpg
02:00 10.000  24.3 -12.0  -3.2  12.4  0-255 q02689.jpg
02:15  5.000  27.8 -11.1  -2.6  18.8  0-255 q02693.jpg
02:30  2.000  31.2 -10.0  -1.9  36.1  0-255 q02696.jpg
02:45  0.800  34.6  -8.9  -1.1 103.6  0-255 q02698.jpg
03:00  0.300  38.0  -7.6  -0.0 153.8  0-255 q02700.jpg

exp: Exposure time in seconds (400 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).