Rocket Skyglow over Pasadena

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Click image thumbnails to enlarge

High Resolution Image

Quicktime movie of trail

I was fortunate enough to be photographing a new building on the Caltech campus on the evening of 9/19/02. While that particular experiment in nighttime photography had produced ultimately forgettable results, while moving to a new location I happened to look to the west around 7:40 PM PST and notice this spectacular trail left by some unspecified rocket launch from Vandenberg. I was quite astonishgly lucky to have my good camera already in-hand and attached to a tripod the instant I saw it. Moreover I was right next a parking structure with a clear view to the West. All I could have hoped for was to have noticed it a few minutes earlier!

Over the roughly half-hour during which it was visible its brightness was initially quite remarkable as the upper portion of the trail was fully illuminated by the sun while Pasadena was deep within the Earth's shadow. The trail became increasingly reddened at lower altitudes. At times the colors were opalescent, similar to colorful refractions I've seen in high altitude clouds during the winter. These refractions are particularly visible in the high resolution image; all those rainbow bands are real features and not imaging artifacts!

As the main trail fell into shadow the sky became increasingly dominated by a blue luminescence at higher elevations than the main trail which appears to have been there for some time, but was largely lost in the glare of the brighter glow. This faint blue luminescence appeared to persist far longer than could be expected from upper atmosphere illumination by direct sunlight, and the color remained consistently blue as it faded rather than turning increasingly red as did the other segments of the trail. I suspect this glow may have been a lingering phosphorescence of some material introduced into the upper atmosphere originally exposed to direct sunlight, or perhaps a fluorescence induced by scattered UV in the upper atmosphere.

The image sequence above spans 15 minutes at roughly even intervals, starting at 7:41 and ending at 7:55. The blue luminescence continued to be visible for at least another 10 minutes though it grew increasingly faint. The quicktime movie is my best effort at registering all the images I took, though it was complicated by the fact I moved the tripod several times. It is somewhat dark and best viewed on a bright monitor. It makes the dynamics of the rocket trail very easy to follow, though.

Some news stories on this Vandenberg launch of a Minuteman III missle (which appears to have been visible from Orange county out to San Jose and as far east as New Mexico) can be found at

You can also find more information about missle tests and the sky shows at:

Robert Hurt
9/19/02, last updated 9/20/02
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