Category: Astronomy

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.

Crescent moon and Venus in the morning sky

One of the advantages (and their aren’t many) of working shift work is that you get to see a lot of sunrises. While many marvel about beautiful sunsets, far fewer can say the same of the sunrise.

Crescent moon and Venus in morning twilight.
Crescent moon and Venus in morning twilight.

I wish I could say that I planned this photograph and was patiently waiting for the right moment. But, no, I wasn’t even paying attention to the sky. On impulse, I walked to the window and peered out to see if there were any clouds lit up by the not-yet-risen sun and was pleased to see the thin crescent moon so near the planet Venus. Luckily, the camera was nearby and I shot this image of the celestial pair with some trees in the foreground to add some detailed texture.

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.

Light pollution in the night sky

Earlier this month it was apparent that there would be one final night of exceptionally clear skies before the summer monsoon pattern set up and skies would be cloudy more often than clear. I thought another night sky image with reflections of the stars in water might be interesting so I ended up at Lake Mary a few miles southeast of Flagstaff. I was surprised to see how much light pollution there was in the southern sky. This stray light is coming from Phoenix, located over 100 miles to the south. There is so much light that it is even reflected in the lake — as are a few of the stars.

Light pollution from distant Phoenix
Light pollution from distant Phoenix

A very short distance to the north of where this image was taken is the Anderson Mesa astronomical station. It’s hard to believe that they can still gather useful observations of the sky with this much light pollution. Finding truly dark skies is becoming a global challenge.