2012 Noctilucent Cloud Season FINISHED now, next opportunity late May 2013.

Link: [2012 Sightings]

All pilots know the basics of precipitation, super-cooled water droplets, and condensation nuclei (CCN) from pollutants and natural aerosols. But in turns out the primary source of condensation nuclei up at this height are thought to be some of the 100 tons of cosmic dust and micrometeorites that the Earth collects every day. NLC research is on going.

Lastly, it turns out that it is rather tricky to actually see Noctilucent Clouds. The season is only from late May until mid August. You need clear skies which are often obscured by low maritime cloud in the Arctic. You must be far enough north, usually well above 50º, which rules out most of the world's population. NLC are only exceptionally visible from America or London. Northern Canadians, Scots, Scandinavians, Russians and Alaskans share an advantage. If you are too far north, you can't see them because it doesn't get dark. The sun needs to be well below the horizon which happens to be very late at night when most of us are asleep. If everything is working for you, then you still have to be in the right place at the right time with a display occurring. Aircrew have the advantage if you can get a twilight route on a great circle track between Europe and N. America in season.

Did you know that some Orbital Science [OS] pilots flying an ex-Air Canada Lockheed L-1011 airliner launched the AIM [AIM] satellite to study Noctilucent Clouds? They used the airborne Pegasus-XL rocket to put the AIM satellite in high polar orbit to learn more about NLC's water, temp, and dust. That same aircraft also put up a Canadian satellite [ACE] that studies atmospheric ozone, related to the Nacreous Clouds below.

Modern digital cameras can make NLC photography pretty easy. Hold the camera still and click in Automatic for starters. Other things to try include: turn your flash off, support camera still, manually focus to infinity, turn night mode on, activate noise reduction, compensate exposure +/- 1 or 2 as required, or use manual settings.

Other interesting high altitude clouds are Nacreous Clouds, also known as Polar Stratospheric Clouds (PSC), which are 50,000 to 80,000 feet high. They are a rare stratospheric cloud which is known as the "Mother of Pearl" cloud because of the iridescent multi-color look that it has. They are most common at winter in the southern Antarctic over Antarctica where temperatures are coolest and only a handful of researchers can witness them. However, they can rarely appear in the high northern Arctic in winter often associated with a stratospheric wave which creates a further dip in temperature allowing them to form. Temperatures must be below -78º C. Opposite to NLC, these PSC clouds are a winter phenomena that increase with the lack of sunlight in the arctic and cooling during winter. Very quickly, as the sun first emerges with Spring, a chemical reaction related to the evaporation of these clouds causes ozone depletion and creates the infamous Ozone Holes (Ozone Hole) that allow ultra violet radiation (UV) to the surface. Global warming at Earth's surface causes atmospheric expansion and cooling at high altitudes which should cause more PSCs in the future.

 In the tropics, a completely unrelated but similar looking (and smaller) "mother of pearl" cloud may sometimes be witnessed when a giant thunderstorm manages to punch into the stratosphere. Occasionally, iridescent Pileus Cap Cloud (more) may be seen.

Astronauts have successfully filmed them using special high-speed low-light video cameras. There are also a few permanent research stations. The Yukka Ridge Field Station [YRFS] in Colorado, USA overlooks the great plains and often gets amazing results. Occasionally amateurs are now getting good video of them as well due to the affordability of high-end electronics and specialist software. Although they seem to be associated with particularly energetic thunderstorms that produce "Spider Lightning" and "Positive" lightning, there is otherwise no way of predicting them and their appearance seems a bit random.

There was a false rumor, started due to a defective photo, that a Sprite contributed to the failed reentry of the Space Shuttle Columbia in 2003 with another proven documented fault. However, no Sprite/Aircraft encounter has ever been witnessed and so avoidance should be strongly considered. It is considered very likely that an unmanned high altitude NASA balloon was downed by a blue jet in 1989.

Despite being very rare, Sprites and Blue Jets can be seen from aircraft, given the correct conditions, as I have personally witnessed several myself. Aircrew can assist researchers with observations by noticing the location and time for later analysis. Researchers will cross reference with archived weather satellite images to try to learn more [Report Form].

The concept of "Dark Lightning" may be of further interest [NASA-YouTube].

A great photograph (lower left) of a meteor train was taken 17 Nov 1998 by Ghazalah Al-Abed over Jordon [Jordanian Astronomical Society] about 20 minutes before sunrise.

A bright meteor, thought to be a small asteroid, was seen overhead the Canadian Yukon on 18 Jan 2000. It illuminated the sky like daylight and left a train that lasted 10 to 15 minutes [Story]. Ewald Lemke photographed the animated sequence at left in morning twilight. Later, NASA sent its research modeled U2 aircraft  high in the Stratosphere to collect some of its dust particles [NASA] and the search was on for pieces that may have hit the ground [Wiki].

Below is a spectacular image of a meteor train following a bright fireball on 19 Nov 2006 over Ireland. Conor McDonald of the Northern Ireland Astronomical Society [EAAS] and colleagues witnessed a -10 Fireball whose bright train lasted for 7 minutes while he took photographs. If you compare dates of these photos, you will notice many of these trains are reliably caused by Leonids Meteors. NASA studied this shower a few years ago during its peak using airborne observatories, flown by your NASA colleagues [Airborne Trains].

Above is another shot of a meteor train, oddly resembling a rocket plume. It was taken by Mr. Don Brown of Park City, Utah Dawn 18 Nov 2009, Rocky Mountains, USA. A bright meteor fireball over Utah left a remnant "train" in the upper atmosphere that was observed with first light, hours later, during dawn Wednesday 18th November 2009. Did you see a cloud resembling a rocket plume high above you before sunrise? It would have been visible for quite a distance from Utah or Colorado. [more], [more2] Utah, USA. Please contact me if there are any airborne images of this event.

Big rockets like the old Saturn V or Space Shuttle can burn 15 tons of fuel in a second on takeoff. That is enough fuel to keep a Boeing 747 jumbo jet up in the air for 1 1/2 hours, so obviously there is going to be some kind of plume (Wiki) left behind. In 6 second, its the same amount of fuel for a jumbo to go from Los Angeles to London! The fascination with plumes is that it allows you to briefly comprehend the height and distance of the rocket that you would otherwise have no reference to judge. For just few minutes things that are truly far away seem incredibly close, before our perspective returns to its domestic normality. It gives us a chance to perceive that space is very far away, yet incredibly close at the same time.

For the foreseeable future, plumes are a required part of getting into space. The only way to get a payload up there is to exert a huge amount of energy which requires rocket engines. Solid fuel rockets, such as those attached to the Shuttle, are even more efficient. Its ironic that although the Space Shuttle has done enormous work researching the Ozone layer [Ozone], it has also contributed to its demise [Rockets]. Its plume has provided aerosols that have assisted Stratospheric Cloud "Nacreous Cloud" creation and ozone depletion. Further, its exhaust has also added moisture to help form the much higher Mesospheric Clouds "Noctilucent Clouds" [Shuttle NLC], [Noctilucent].

These releases are very high and can be seen from hundreds of miles away. If you live near an active space launch facility then you will eventually see one. As an example, observers as far away as Phoenix can sometimes witness a display over Vandenberg near Los Angeles. There are some useful Vandenberg plots [Space Archive] which can assist in observing these plumes. Michael J O'Leary managed to get a very good animated sequence [Extremely-cool-gif] of a Minotaur release in 2005.

In 2009 there was a totally bizarre sight over Russia's White Sea that was witnessed by people nearby in northern Norway. A ground shot taken by Mr. Jan Petter Jorgensen, in the early dawn of Wednesday 9 Dec 2009 shows a distant illuminated missile plume, followed by bluish fuel venting, and an unusually giant luminous spiral from a destroyed satellite. Please contact me if you saw this phenomena from the air. [more1], [more2], [more3], [more4], [more5]

Although I have never seen a photo, I have heard first hand from several aircrew who have seen Ball Lightning [link]. If anyone ever gets an image, please send it into me.

Other fascinating sights are Halos [Wiki], [Atmospheric Optics]. These eye-catching perfectly-round circles and their associated bits are caused by ice crystals [Atmospheric Optics]. The standard 6 sided shape of a slowly falling gravity-aligned ice crystal is responsible for most of these sightings, but rarer affects are possible. From the ground, these ice crystals are often many miles away at heights over 30,000 feet. However, from the aircraft they could be just in the air around your immediate vicinity and a small climb of less then 200 feet may get you completely clear of the affect. The most common observations include the 22º Halo, followed by the left and right Sundogs [Wiki], and vertical ice Pillars [Wiki].