ISS, Soleil et Paysage urbain

[Fred_76]

Bonjour

 

Je pense que Thierry Legault va relever le chalenge, en tous cas ça ne sera pas simple :

 

https://www.facebook.com/groups/nightscaper/permalink/2251426915168222?sfns=mo

 

Une photo de Paul Schmit :

 

STACKED (sort of)

"Space Station at Sunrise"

I’m pretty sure this is a first. This morning, I captured the most difficult and technical astrolandscape shot I've ever planned and executed.  For over a year, I've been waiting for an opportunity to capture the International Space Station moving across the face of the sun as it rises over a landscape.  This turns out to be an immensely challenging task, requiring that the ISS cross in front of the sun far enough from my vantage point so that its apparent elevation is relatively low in the sky (then allowing for a landscape element); plus, the ISS shadow can't just be low in the sky, it also must pass over a suitable, well-positioned landscape element; plus, there must be a way to get to the exact location that will afford a simultaneous view of sunrise over that landscape element (~2 minute event) and the ISS transit (~1 second event).

A few weeks ago, an opportunity finally appeared near my home in Albuquerque, where the ISS would transit the sun in the morning while the sun was ~16 degrees above the horizon, low enough in the sky to capture the transit as the sun rose over the 10k-foot mountains west of town.  Furthermore, a network of hiking trails cutting through the northern foothills region seemed to offer perfect access to an area that aligned this event with some prominent radio towers at the mountain peak.  A previous attempt to capture a similar transit at moonset earlier this year revealed that planning a shot like this pushes typical astrolandscape planning software (TPE, PlanIt!, etc.) to its limits, where tiny errors in perspective (~0.1 degrees) caused by inaccuracies in the topographical mapping software could make or break a shot.

Determined to capture this scene and aware of the shortcomings of my planning software, I did a full-scale dry run yesterday morning, hiking out to my shooting location and capturing the sun rising behind the radio towers at nearly the same time as today's transit.  Once again, very small errors in the software's landscape rendering led to the sun rising ~1 minute later than expected, signifying a mere 0.2-degree error in simulated perspective, but enough of an error that I would have missed the transit while waiting for the sun to rise.  After the dry run, I adjusted my location for this morning's shoot both to account for the slightly different position of the sun a day later, and attempting to build in margin knowing that the landscape rendering in this area was producing a slight delay in predicted sunrise.

The culmination of this significant effort ended in pretty spectacular fashion.  I arrived on location this morning with an hour or so to spare and set up my rig on a hillside with the camera/telescope oriented toward the radio tower.  However, as the moment approached, I quickly found that I slightly overcompensated with my repositioning as I watched the sun appear from behind the mountain peak about a minute earlier than expected.  In this intense moment, I reasoned that from this spot, I'd be lucky to catch the tops of the radio towers at the very bottom edge of the sun's disk at the time of the ISS transit.  With not even 2 minutes to go before the transit, I quickly slid my telescope/camera off its sturdy mount, tucked it under my arm, and ran 40 feet down the hillside, chasing the shadow of the mountain as it crept downhill.  With only 45 seconds to go, I laid on my back, propped the telescope on my knees, and frantically scanned back and forth trying to find the sun in my LCD screen (tough to do when the solar filter prevents you from seeing anything but direct illumination from the sun, and when your field of view is only about 1 degree).  Somehow, at the last second, the sun's disk jittered into view, and I ripped away 10 frames per second as the sun bounced around on the back of my screen due to extreme camera shake.  By the time I snapped the first image, the ISS had just begun its 1.4-second transit across the sun (usually I add 4-5 seconds of buffer time to avoid missing these fleeting events), and somehow, I caught the entire transit.  Sure, there is some minute pixel-level blurring due to handholding a telescope at ~2000mm FF-equivalent focal length after sprinting downhill, and yes, I risked missing the event completely had the sun not suddenly appeared on my LCD screen at just the right moment.  But, with that in mind, I think the final image is much more dramatic with individual trees and branches appearing below the radio towers, captured from over 3 miles away by a photographer fearing he just ruined countless hours of preparation and missed the shot.

Oh, and within two minutes of capturing this sequence, the sun disappeared behind a bank of high clouds.  😉

EXIF:

1300mm f/13 Mak-Cas telescope + Nikon D500 = 2000+mm full-frame equivalent focal length, handheld!  ISO 3200, 1/2000s shutter speed, full-aperture solar filter.

SOCIAL:

Instagram: @paulschmitphotography

Website/Prints: https://www.PaulSchmitPhotography.com 

 

Impressionnant !

 

a+

 

Fred

[sebseacteam]

Il fallait la faire en effet.

Prochain défi : la même configuration quand le soleil se couche sous l'Arc de Triomphe à Paris ? 

[iserois]

Superbe prise,merci du partage !

[Jean Louis]

Bonjour Fred,

 

Merci du partage,vraiment original,pas dénué d'esthétique😎

 

Jean Louis