To Catch A Falling Star: On A Perseid Trail

A glimpse of the Perseid meteor shower caught on camera on the Aug 12-13 night from my backyard. In this composite frame, four streaks can be seen (5 if you have a keen eye) through severe sodium vapor light pollution from the ground and the glow of a full moon behind camera.

Trailblazers

Lewis Swift

Horace Tuttle

Every year, starting in mid July and peaking mid August, the earth runs into orbital debris left behind by the periodic comet 109P/Swift-Tuttle. The comet was discovered independently 1862 by two Americans - hardware merchant Lewis Swift, and astronomer / war veteran Horace Tuttle.  However it was not until 1865 that Italian astronomer and science historian Giovanni Schiparelli connected it to be source of the Perseids. 

The comet Swift-Tuttle comes around every 133 years and is estimated to have a nucleus of 16 miles (26 km) - or twice the size of the one that is hypothesized to cause the demise of the dinosaurs on earth.

Some of the pieces plunge into the atmosphere burning up as they fall. While not stars, meteors are also called shooting stars - just what they look like by naked eye. 

Unprepared

The Perseids are supposed to be one of the most predictable and prolific meteor showers of the year with 50-100 meteors predicted per hour. What adds to its popularity is the warm summer nights that make observing pleasant as opposed to freezing winters. But this year the prevalent advice was to skip the show since there would be the full moon out at the time - washing out most of the meteors from view. So despite having clear skies, I did not prepare for this. On the night of the 12th (rather 13th morning) I happened to wake up post midnight and decided to take a peek outside. And across the clear night skies, I saw two meteors by naked eye in a short span. That is when I decided to try my luck and see what I could “catch”. 

In the past I have set up the camera on an ordinary tripod left hooked up to an intervalometer. However the shifting skies with this method causes an issue later when stacking multiple frames. To increase the chances of catching a meteor, I use an ultra wide lens (A Tokina set at its widest at 11 mm).  While that catches a wide swath of the sky, wide lenses naturally cause distortion of the image near the frame edges. As the constellations shift across frame over the night, the shape distorts slightly. As a result when stacking multiple shots, the star points do not exactly line up. To get around this, I used a tracking mount that keeps the same patch of sky in frame as the constellations shift. pointed at the constellation of Perseus where the radiant is supposed to be. And then, having set my “digital wolves” on the prowl, I went to sleep. 

What the Wolves Dragged In

Morning revealed a crop of 400 individual snapshots. With it came the chore of identifying which ones had caught a meteor trail while weeding out satellite flares and airplanes from candidate frames. That night, between 3:30 a.m. and 4:30 am, there were five frames which actually had meteors in them, so about 5 meteors per hour. Next step was to create a composite by aligning and stacking these individual images. I used the Sequator software to do this (thank god for free software). This was followed by removing noise with TopazDenoise AI (not so free), manually adding the constellation stick figure overlay and doing some minor enhancements using GIMP. All of this took all morning.  And the result is the composite shot on top.  

Radiant

A Perseid meteor near the Pleiades cluster and Mars (left)

The aligned shot clearly shows that regardless of where the radiant is supposed to be, the Perseids seem to fly in all directions. 

When some floating rocks in space encounter a lumbering earth hurtling towards them plucking them off their nesting orbits by its enormous gravity, there is no telling which way they will fall.

In the individual shots, the hint of green yellow and red within the streaks are the chemical signatures of the rocks as they burn up at the edge of the stratosphere. These little flourishes are a gentle reminder that when most humans lay asleep in bed, nature may quietly be putting on perhaps the most spectacular fireworks show on earth miles above them, one shooting star at a time.

A Perseid meteor between the Double Cluster (left) and the Pleiades (right)