NLC 2017-07-20/21
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: 2017-07-20/21
UT forms bright height azimuth comments
ness top bot left rght e.g. weather
-------- ----- ------ --- --- ---- ---- --------------------------------
21:15:01 X patchy cloud
21:30:01 X widespread cloud
21:45:07 X almost overcast
22:00:08 X almost overcast
22:15:10 X almost overcast
22:30:32 X patchy cloud to h 20
22:45:32 X cloud to h 5, patches to h 15
23:00:52 IV 2 9 330 cloud to h 5
23:15:53 IV 2 8 <325 25 cloud to h 5
23:31:24 I,IV 2 8 <325 25 cloud to h 3
23:46:24 I,IV 2 6 330 25 cloud to h 3
00:01:24 II,IV 2 6 325 35 cloud to h 2
00:16:23 II,IV 3 7 325 >35 cloud to h 2
00:31:24 IV 3 8 325 >35 cloud to h 2, patches above h 25
00:46:24 IV 3 8 325 35 cloud patches above and on right, aircraft
01:01:23 IV 3 8 340 cloud patches on right
01:16:24 I 2 9 340 cloud patches on right
01:30:53 I 2 10 335 >35 cloud patches on right
01:45:53 I 2 13 340 >35 cloud on right to h 3
02:00:32 I 2 15 340 >35 almost clear
02:15:19 I 1 20 355 30 almost clear
02:30:09 X widespread cloud patches
02:45:06 X widespread cloud patches
03:00:05 X widespread cloud
03:15:02 X cloud to h 15
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: 2017/07/20-21
Start: 23:00
End: 02:15
Forms: I,II,IV
Max elevation: 3
Max brightness: 3
Comments: Through cloud.
http://www.chiandh.eu/nlccam/20170720-21.shtml
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) -------- ------ ----- ----- ----- ----- ----- ------------------- 23:00:52 15.000 341.3 -11.8 -3.1 13.2 0-255 q3448.jpg m3448.jpg 23:15:53 15.000 344.8 -12.4 -3.5 10.3 0-255 q3454.jpg 23:31:24 30.000 348.5 -12.9 -3.8 8.5 0-255 q3460.jpg 23:46:24 30.000 352.1 -13.3 -4.0 7.5 0-255 q3466.jpg 00:01:24 30.000 355.7 -13.5 -4.1 6.9 0-255 q3472.jpg 00:16:23 30.000 359.3 -13.6 -4.2 6.7 0-255 q3478.jpg 00:31:24 30.000 3.0 -13.6 -4.1 6.8 0-255 q3484.jpg 00:46:24 30.000 6.6 -13.4 -4.0 7.2 0-255 q3490.jpg 01:01:23 30.000 10.2 -13.1 -3.9 8.1 0-255 q3496.jpg 01:16:24 30.000 13.7 -12.7 -3.6 9.5 0-255 q3502.jpg 01:30:53 15.000 17.2 -12.1 -3.3 11.6 0-255 q3508.jpg 01:45:53 15.000 20.7 -11.4 -2.9 15.5 0-255 q3514.jpg 02:00:32 8.000 24.1 -10.7 -2.4 23.2 0-255 q3518.jpg m3518.jpg 02:15:19 4.000 27.5 -9.8 -1.7 44.9 0-255 q3521.jpg m3521.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).
