Unusual and Interesting

Today’s post contains an unusual mix of pictures I’ve taken recently. I think their stories are interesting, I hope you will too.

Cristate or “crested” saguaros form when the cells in the growing stem begin to divide outward, rather than in the circular pattern of a normal cactus. This is an unusual mutation which results in the growth of a large fan-shaped crest at the growing tip of a saguaro’s main stem or arms.

The crested saguaro is very unusual, in terms of its rarity and its unusual shape. Tens of thousands of cactuses grow in Saguaro National Park near Tucson. Yet according to the park’s website, roughly 25 crested saguaros have been found within its boundaries.

I’m familiar with the name of the cactus, but I had never seen one before last week. My familiarity with the name comes from the name of a nearby street. I can’t say I wasn’t curious about this rare cactus, but I had not made the effort to find one.  A fortunate stroke of serendipity led me to Phoenix’s Desert Botanical Garden where, lo and behold there it was. Who would have thought!

This next photograph portrays something less down-to-earth, stars. I shot the pictures for this image last evening, 154 in total. I set up my camera to shoot a series of 10 second exposures, over a period of 25 minutes. These pictures were almost identical, the sole difference being the location of the stars in each image. The stars move relative to the earth (and the camera) as it rotates. Stars on each photograph are in a slightly different position as the earth turns. The only star that doesn’t move is Polaris (North Star) because the earth’s axis of rotation points directly at it. To capture this circular pattern of motion, I pointed my camera at Polaris.

As the camera moves with the lens open, the stars it captures are slightly stretched. By stacking and blending all the images, the moving, elongated stars combine to create the streaks you seen in the final photograph. The top image is a single photograph, taken before beginning to capture the “moving” stars. It doesn’t move and isn’t blurred. I also turned off the yard lights once I had taken the stationary image, so they wouldn’t be part of the stars blend.

I’m going on an overnight excursion next week. I’m hoping the skies will be clear and I’ll be able to create another star trails picture in a more scenic location. Watch for it.