Noctilucent Cloud Images

Below are a series of images of the 2001 June 24/25 NLC display. This was a remarkable display which was extremely bright and showed many different types of NLC.

The the display was photographed using an Olympus OM-1n with a 28mm lens at f2.8 using Fuji Reala ISO 100 film. The various exposure times are shown underneath the image and just go to show that exposure bracketing is essential. As you can probably see this was my first time at shooting NLC with the 28mm lens and consequently I tried to make composite images as I thought the lens would not cover the whole of the display. I was wrong! This doesn't detract much from the image though. I also think that some of the exposure times were slightly too long as the centre of the display is quite overexposed. However, shorter exposures may not have captured as much detail at the edge of the cloud, hence a subtle balance is usually required! It is worth noting that these images are of a much poorer quality than the actual photographic emulsions and have been sharpened somewhat to show greater detail.

23.05UT. 5 sec. exposure. As you can see there is a very prominent patch of both Type II and III cloud at the upper left of the display. The vast body of the NLC is composed of Type IIa and Type I. The NLC had a brightness of between 4-5 with an altitude of ~22 degrees and covered 328-047 degrees azimuth.

23.20UT. 3 sec. exposure. Once again a large clump of Type III cloud is visible to the west of the display. It is immediately obvious that this structure has become much more defined and ripple-like than the earlier image. The vast body of the NLC is composed of Type II and Type I NLC. There is much change visible in this image, all over a timespan of 15 minutes, along with a very general trend of the NLC structure towards the east. The NLC had a brightness of 4-5 with an altitude of ~30 degrees and covered 328-036 degrees azimuth. From the azimuth data it is possible to state that the cloud is either expanding or parts of the cloud are moving eastwards.

23.35UT. 10sec. exposure. The clump of Type III NLC has decreased in size over the past 15 minutes but the remaining portion has become much more defined and wavy. There is a hint of Type III NLC becoming more dominant throughout the display (not clearly visible in these images but visible on the originals). Type II NLC is still visible throughout the display. Tropospheric cloud is statring to obscure the base of the NLC slightly. Notice Capella standing out prominently to the right of the centre of the image. The NLC had a brightness of 4-5 with an altitude of ~20 degrees and covered 328-030 degrees azimuth.

00.05UT. 10sec. exposure. The Type III NLC to the west has all but disappeared and a dominace of Type II is visible. Type I patches of a bluish colour are also visible. Notice the finer Type II and III to the uppermost portions of the display. The display is becoming more compact in size. This could be due to movement of the NLC, actual shrinkage or encroachment of dawn. The NLC had a brightness of 3 with an altitude of ~20 degrees and covered 338-028 degrees azimuth.

00.35UT. 8 sec. exposure. Type II and III are visible in the display but become much fainter as sky brightness increases. Shrinkage of the display is clearly evident in this image. The NLC had a brightness of 3 with an altitude of ~12 degrees and covered 342-016 degrees azimuth.

00.50UT. 5 sec. exposure. Some very faint Type II NLC is visible. The display has all but vanished in the brightening sky. Eight minutes later the observing session was halted. The NLC had a brightness of 2 with an altitude of ~10 degrees and covered 352-008 degrees azimuth.