How To Observe Noctilucent Clouds
Observation -For convenience, printed observing sheets are available for download at To be confirmed
NLC, unlike the aurora, change fairly slowly during a night and observations should if possible, be made at 15 minute intervals, i.e. on the hour, quarter past etc. They can then be compared with those or other observers. Drawings are very useful, and more especially, photographs. For a 200 ASA film 8 seconds at £ 2.8 should give good results. Keep a note of times and exposures on the back of the form.
Your report should include –
Place of observation with latitude and longitude to the nearest half-degree.
The date. Always use the “double-date” for a single night. Thus ‘June 13/14 means the night of the 13th and the early morning of the l4th.
The time. If you use local time, state how it relates to UT, or use UT. Always state the time system you are using e.g. BST.
If you use the forms, write in column 2 :
NLC if there is definitely noctilucent cloud present,
0 if noctilucent cloud is definitely absent, if clear,
X if no decision is possible because of mist, cloud etc.
AZIMUTHS – if NLC is present try to measure the left-hand and right-hand azimuths of the total limits of the display, but azimuths of the individual bits of it are not necessary. If you use a prismatic compass correct the magnetic bearings to true bearings. Use the 0 – 360 convention, i.e. 000 is north, 090 east, 180 south, 270 west.
Elevation – measure, if you can, the elevation of the upper border and, if there is one, that of the lower border. There are various kinds of simple alidade you can make for this.
Brightness – If the NLC is faint or visible only with binoculars write “1”, if intensely bright and vivid call it “3”, otherwise write “2”.
Structure – I,II,III,IV or any combination of the four ( see illustrations below).
Observing Conditions – it helps to describe these very briefly, e.g. cloud cover, haze, bright moon.
Aurora – if you see an aurora please describe it in detail on the back of the form because the simutaneous occurrence of the two upper atmosphere phenomena is unusual and is of great theoretical interest.
| The British Astronomical Association supports amateur astronomers around the UK and the rest of the world. Find out more about the BAA or join us. |