Tag: International Space Station

The final flight of the Discovery

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An era has come to an end as the NASA space shuttle Discovery landed earlier this week after a successful mission to the International Space Station (ISS). This was the last flight for Discovery and it will now be retired to a museum.

After Discovery undocked from the ISS their orbits began to separate with the shuttle flying across the sky a few tens of seconds earlier than the ISS. On the night before returning to Kennedy Space Center, the ISS and Discovery made two evening twilight passes across the southwestern United States.

ISS and STS-133 transiting the northern sky above the San Francisco Peaks.
ISS and STS-133 transiting the northern sky above the San Francisco Peaks.

The first pass came early in the evening with a still bright twilight sky. The ISS and Discovery only rose to about 17 degrees above the horizon and this made it easy to capture an image with the San Francisco Peaks and the Kachina wetlands in the same photograph.

ISS and STS-133 climbing out of the western sky and entering the Earths shadow as they approach the lunar disk.
ISS and STS-133 climbing out of the western sky and entering the Earths shadow as they approach the lunar disk.

About 95 minutes later a second pass occurred. This time the two spacecraft arose from the western sky and climbed higher towards the crescent moon before disappearing into the Earths shadow.

Only two more shuttle missions remain and then, truly, it will be the end of an era.

Watching the International Space Station amidst the scenery of Sedona

As readers of this site already know, I enjoy photographing the International Space Station (ISS) as it makes its twilight flyovers. Most of my ISS images have been taken in Flagstaff and nearby environs. Recently, however, I made a trip to the lower elevations of Sedona to attempt to photograph the ISS amidst the scenery of Sedona.

This transit only got to about 20 degrees elevation above the horizon so it was important to find a location with a good view to the northwest — but also an interesting view. After looking at the ephemeris for the transit (rise time, highest elevation, set time, etc.) I decided that I could get an interesting photograph from the Brins Mesa trailhead area north of Sedona.

We arrived about 15 minutes before the transit so there was enough time to survey the area and select the most appropriate spot to set up the tripod and camera. After a few test shots, I was ready for the transit. Unfortunately, I wasn’t paying close attention and I missed the first 10-20 seconds as it rose in the west. No problem! I started the camera but then realized I had failed to set the shutter to continuous shooting mode. I use continuous mode so that I can take a series of 10-15 second exposures then composite them later. By keeping the exposures short there is less chance of overexposing the twilight sky.

All was not lost as I only missed the first two 10-second images but managed to capture the next seven images. After compositing the individual images in Photoshop and using the Lighten blend mode, I got the following result:

International Space Station (ISS) transiting the evening twilight sky in Sedona, Arizona.

There was a bit of camera shake in the first image as I was still fiddling with camera settings while the shutter was open! But overall the image managed to capture what I set out to do: photograph the ISS as a long streak of light with the fabulous Red Rocks of Sedona as a foreground.

International Space Station transits

A few weeks ago we had a couple of nights in which the International Space Station (ISS) made some evening twilight transits that were visible across northern Arizona. The first night the ISS transited from the northwest across the sky to the east. As it swung across the evening sky it passed near Mizar in Ursa Major then near Polaris in Ursa Minor. The following night it traveled from west to southeast and passed near the Moon and Jupiter before it entered into the Earth’s shadow.

International Space Station transiting the skies across northern Arizona.
International Space Station transiting the skies across northern Arizona.

Both of these final images are composites. Each was shot with a 16mm ultra-wide angle lens at f/4.0, ISO 800, and 10s exposure. For the photograph above, 16 images were composited. For the photograph below, seven images were used. In Photoshop, images are assembled as layers then blended using Lighten mode. This allows the streak of light from the ISS to show through all layers. The advantage to this method — compared to a single image of longer duration — is that the sky does not become overexposed. Instead the result is a dark background upon which the ISS flies.

International Space Station transiting the skies across northern Arizona.
International Space Station transiting the skies across northern Arizona.

Both images were taken at the Kachina Wetlands located a few miles to the south of Flagstaff, Arizona. This location provides wide open skies for viewing objects low on the horizon and offers ponds of water that produce wonderful reflections of the stars.

To find out when the ISS will fly across your area, visit either of these sites:

SpaceWeather.com

Heavens-Above

International Space Station transit at twilight

The other day the International Space Station (ISS) made a transit of the western sky during twilight. Low on the horizon was the planet Venus with the ISS streaking across the sky above. I’ve been shooting images of the ISS for a year or two but think this is one of the best. It works for a number of reasons. One is the bright twilight on the horizon deepening into dark night sky above. The planet Venus — and its reflection in the water — add a counterpoint.

To create this image I set the camera on continuous shoot and then used the remote release to start. The images are ISO 200, f/4.0, 28mm wide angle lens, and 10s exposures. Five images were taken so this is 50 seconds of transit.

I opened all five images in Photoshop with each image a layer. Because 50 seconds is long enough for stars to leave trails across the sky — even with a wide angle — I wanted to only use one sky layer. In the other four layers I masked the stars and sky and left only the track of the ISS. The result is sharp points for the stars and Venus and a smooth track for the ISS.

Twilight transit of the International Space Station (ISS).
Twilight transit of the International Space Station (ISS).

To get daily updates on transit times of the ISS — and other space satellites — I use the following two web sites:

Spaceweather.com (http://www.spaceweather.com)

Heavens-Above.com (http://www.heavens-above.com)

Satellite transits and wildfires

The satellite flyby tables (mentioned in a previous post) indicated that there would be a favorable pass of the International Space Station this evening. The ISS would pass by Saturn, Mars, and Venus in the course of a minute or two in mid evening.

I wandered out to the Kachina Wetlands hoping to get good star and planet reflections in the water. It had been windy all day but by evening the wind had diminished and the water was smooth and glassy. Perfect for reflections.

It’s a tradeoff when it comes to shutter speed when imaging a transit of the ISS. A longer exposure will produce a longer track of the ISS while a shorter exposure will result in sharp points for the stars instead of blurred tracks. After a few test shots I decided that 20s was about right. Below are two images of the ISS. The first includes a very bright Venus near the horizon as well as its reflection with the ISS moving below the planet Mars (above and left of the track).

ISS passing by Venus, Mars, and Saturn in the evening twilight sky.
ISS passing by Venus, Mars, and Saturn in the evening twilight sky.

The second image was taken as the ISS was descending into the northern sky with the San Francisco Peaks in the background.

ISS descending in the northern sky with the Kachina Peaks in the distance.
ISS descending in the northern sky with the Kachina Peaks in the distance.

While setting up for the ISS transit I was saddened by the view of the Schultz Wildfire burning in the San Francisco Peaks. This fire has already burned over 14000 acres and is only partially contained. Many trails and forest service access roads have been destroyed by this fire. And, yet, the glow in the evening twilight and its reflection was fascinating.

Schultz Wildfire burning in the Kachina Peaks.
Schultz Wildfire burning in the San Francisco Peaks.