chi and h site logo

NLC 2010-07-17/18

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: Stichill Eastfield, 55.7N 2.4W
          unattended dSLR with limited field of view A ~310-20, h ~0-40
          images every 15 min
Date: 2010-07-17/18

  UT   forms  bright   height   azimuth   comments
               ness   top bot  left rght  e.g. weather
-----  -----  ------  --- ---  ---- ----  --------------------------------
21:15  X                                  thin cover of cirrus
21:30  X                                  thin cover of cirrus
21:45  X                                  cirrus to h 20
22:00  X                                  cirrus to h 15
22:15  X                                  cirrus to h 10, cloud to h 25 on left
22:30  0                                  cloud on left and above h 20
22:45  NLC?             4         5   15  cloud patches on left and at top
23:00  II          1    4         6  >15  cloud on horizon on left, minor patches up high
23:15  II          1    4      <360  >15  cloud on horizon on left
23:30  II          2    4         0   15  cloud on left
23:45  IV          2    5         0   12  cloud on left and above
00:00  NLC         2                      through cloud
00:15  X                                  only part of field clear, lightbox
00:30  X                                  almost overcast, lightbox
00:45  NLC                                through cloud, lightbox
01:00  X                                  almost overcast, lightbox
01:15  X                                  almost overcast
01:30  X                                  overcast
01:45  X                                  overcast
02:00  X                                  overcast
02:15  X                                  overcast
02:30  X                                  overcast
02:45  X                                  overcast
03:00  X                                  almost overcast
03:15  X                                  cloud to h 20 or 30

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: Stichill
Date: 2010/07/17-18
Start: 22:45
End: 00:45
Forms: II,IV
Max elevation: 5
Max brightness: 2
Comments:
<a href="http://www.chiandh.me.uk/p/NLC_2010-07-17/18">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)
----- ------ ----- ----- ----- -----  ----- ---------------------
22:45  4.000 338.5 -10.9  -2.5  20.6  0-255 q31943.jpg m31943.jpg
23:00 15.000 342.0 -11.6  -2.9  14.5  0-255 q31949.jpg m31949.jpg
23:15 25.000 345.5 -12.2  -3.3  11.3  0-255 q31955.jpg m31955.jpg
23:30 30.000 349.0 -12.7  -3.6   9.5  0-255 q31961.jpg
23:45 30.000 352.6 -13.0  -3.8   8.4  0-255 q31967.jpg
00:00 30.000 356.2 -13.2  -3.9   7.7  0-255 q31973.jpg
00:45 30.000   7.0 -13.0  -3.8   8.2  0-255 q31991.jpg m31991.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).