Back in late summer, Â I had a chance to capture multiple long-exposure images of a portion of the Milky Way that is rich in star clusters, nebulae, and dust clouds. I had seen some onlineÂ images of theÂ Lagoon Nebula (M8) and was certain that it was bright and large enough to capture with a DSLR camera and small telephoto lens.
The image above is a stack of 11 photographs. Why stack multiple images?Â Single exposures of the faint details in the night sky will usually have a lot of noise. Â Stacking multiple exposures will help eliminate random noise in the image and improves the overall signal-to-noise ratio. Even Hubble Space Telescope stacks images!
These images were shot at ISO 800, 60 second exposure, and f/2.8 aperture. The lens is the Nikon AF-S NIKKOR 85mm f/1.8G. The camera was mounted on anÂ iOptron SkyTracker. Image stacking was done usingÂ Deep Sky Stacker. The stacked image was then post-processed in Photoshop using theÂ Astronomy Tools Action Set.
After a pair of back-to-back snow storms followed by sub-zero (Â°F)Â overnight temperatures we decided it was time to visit West Fork Oak Creek Canyon and see how the ice was developing.
As anyone who has hiked in this canyon knows, the trail crosses the creek more than a dozen times before the end of the maintained trail. In the summer it’s a simple matter of either stepping on the stones or just walking in the water. Getting wet is not an option in the winter leaving the stepping stones or walking on the ice if it is safe.
Most of the crossings we encountered had a mixture of stones and thick ice and we had no trouble crossing the stream. For additional traction we were using our Kahtoola microspikes.
The very cold temperatures and patches of open water resulted in surface hoar (i.e., fern-like ice crystals directly deposited on snow, ice or already frozen surfaces) developing and creating some interesting textures.
It’s been cold around these parts lately. How cold? Well, we’ve seen -24ÂºF in Bellemont, -19ÂºF in Tusayan, and -9ÂºF in Flagstaff. These are all northern Arizona communities that are used to the cold — but not for this many days in a row. This is the coldest 5-day period in Flagstaff in over three decades.
There are some benefits. With prolonged cold some of the streams in the canyons will freeze. With this in mind, we took a hike up West Fork Oak Creek. The trail was snow packed and icy. Wisely, we all had foot traction gear including instep crampons and microspikes.
The trail crosses the creek numerous times and the first few crossings were tricky but doable. That is, the logs and/or stepping stones were ice covered but sure footing could be found using care and caution.
One of stream crossings, though, stymied us. For whatever reasons, the water and ice level had increased substantially in this location so that all the stepping stones were well under water and ice. And the flow of water had become concentrated along one side of the channel so that the ice was eroded. After studying it for awhile, we reluctantly agreed that the risk of crashing through the ice was too great. We turned back.
In previous years we had easily moved through this crossing and many others farther upstream including the “subway” passage. We had hoped to make it this far and, possibly, even farther upstream. It wasn’t to be.
Still, it’s never a bad day when you are out hiking with no one else around except your friends in an environment not often experienced by most.