Polaris on the Playa

One of the active topics in modern photography is the distinction between “blends” (combining multiple exposures from a single camera viewpoint), and “composites” (which combine unrelated images into a synthetic scene).  Both are valid uses of photography, but I prefer to limit my efforts to the former, hoping to reveal some scientific beauty in the result.

In this case the relative motion of the stars is “stacked” (added) from 2,335 10-second exposures.  Each frame looks like a normal picture of the sky, but when accumulated creates the star trail effect.  The frames were selected from the period after “astronomical twilight” when the sun is more than 18-degrees below the horizon.  On this date, official night lasted over six hours, and the star trails cover more than 1/4 of a full circle (and even Polaris shows that it is not exactly on the north celestial pole).

Although it was “night”, it was not completely dark.  The moon was up and illuminated the scene until it set around midnight.  This allows the foreground to show, including the “sailing stone” with its path on the dry lakebed trailing behind it, a contrast of time scales against the motion of the sky.

A final detail to explain:  the streaks below and to the left are the result of trains of Starlink satellites moving across the sky.  Dozens of satellites follow each other into and out of the sunlight at their altitude, reflecting it down to our observing position on the playa and creating its own trail on this image.

For more of the backstory on making this image and the next, see “A Night on the Playa – Part 2“.

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19 May 2021
Racetrack Playa
Death Valley National Park CA
Canon EOS Ra with EFS 10-22mm
2335 exposures, 8 sec @ f/4, ISO 3200 (6-1/2 hours)


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Wupatki Startrails

“The Citadel” remains the focus for this startrail image.  The moon dominates the scene, and this blend of exposures shows its path among the stars.

The cloud persisted above the monument over the course of the exposure, growing and shrinking, but never moving away or evaporating.

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15 May 2021
Wupatki National Monument
Flagstaff AZ
Canon EOS 6D with Sigma 14mm f/1.8
458 exposures, 8 sec @ f/2, ISO 3200 (76 minutes)


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Moonflowers

I had another camera in the sunflower field.  This one faced south and caught the arcs of stars and planets near the ecliptic.  Eventually the full moon entered the scene.

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2 September 2020
Otsego MN
Canon EOS 6D with EF 17-40mm(@17mm)
Blended 10 sec intervals  at f/4, ISO 800, 1/2 hour elapsed


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Northern Sunflower Trails

I have long been fascinated by sunflowers.  On my travels across the prairies of the Dakotas I loved to encounter sunflower fields with their collective bright yellow heads all aimed in the same direction.  

It is generally known that sunflowers track the sun across the sky, from east to west.  I wondered what happens after sunset, when the flowers would all be facing west.  With no phototropism to guide it, how would they get ready for the eastern sunrise?  Would they be caught off-guard in the morning and suddenly swing their heads back at the risk of floral whiplash?  Or is there a gradual re-setting of the neck-stalk fibers back to an easterly gaze?

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Ayres Natural Bridge Park

The Earth moves under the North Star while the moon illuminates the red rock canyon wall of Ayers Natural Bridges Park.

We were pleasantly surprised to discover this hidden gem in Wyoming, land donated from their ranch by the Ayres family.  The park was entirely free, including campsites, but no pets are allowed.  This is considered a benefit to some.

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10 July 2019
Ayres Natural Bridge Park, Douglas Wyoming
Canon 60Da with EOS EFS 10-22mm(@10mm)
Composited 5-minute exposures at f/5.6, ISO 200, 2-1/2 hours elapsed


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Beartooth Pass at Midnight

I had been here before, in 2001, attempting to recreate a scene of the night sky reflected in a calm alpine lake.  I didn’t succeed then, but here I was with another opportunity.  I’m still not fully satisfied; I guess I will have to come back and try again!

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Beartooth Pass, Montana
25 July 2011
Canon EOS 20Da, 17-55mm (17mm), ISO 1600, f/2.8


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Wild Goose Island

I return to this iconic overlook in Glacier Park and try again.  Previously (2001), the weather compromised the view, tonight it is perfectly clear and the traffic over Logan Pass nonexistent.  The pink smudge to the left is not a cloud, it is the core of the Milky Way, moving its way across the sky on a beautifully clear August night.

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Glacier Park, Montana
25 August 2009
Canon EOS 20Da, 10-22mm (10mm) at f/3.5, ISO 3200
Composited series of 8-second exposures over a duration of two hours


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Serengeti Startrails, North

A safari in Tanzania takes one just south of the Earth’s equator.  Here there is no visible North Star; it resides just below the horizon, obscured by the acacia trees and grasses of the Serengeti plain.   A startrail image reveals its implicit location; the arcs to the north are perfect semicircles.

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Serengeti National Park, Tanzania
14 June 2008
Canon EOS 30D, EF-S 10-22mm at 10mm
composite of 3-minute exposures at f/8, ISO 400


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Serengeti Startrails, East

A safari in Tanzania takes one almost exactly to the Earth’s equator.  A camera pointed east to make a startrail image will show those due-east stars taking paths perfectly perpendicular to the horizon.  Stars to the north and south bend toward their respective centers of apparent motion.

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Serengeti National Park, Tanzania
14 June 2008
Canon EOS 30D, EF-S 10-22mm at 10mm
composite of 3-minute exposures at f/6.7, ISO 400


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Owachomo South

The view to the south at Owachomo Natural Bridge does not include the south celestial pole, but it clearly shows the stars revolving around it. At higher elevations, the stars transition across the celestial equator, and then arc the other way, following the rules for the northern hemisphere.

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Natural Bridge Owachomo (South)
15 Nov 2007
EOS 20Da, EF-S 10-22mm at 10mm
18x5min, f/6.7, ISO 800


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