Using Satellite Data to Anticipate a Great Sunset

November 27, 2020 / Add comment

This sunset from a few weeks ago was pretty spectacular. Drivers were pulling off the highway into the overlook area to get photographs. I overheard one person claiming this was a one-in-a-million sunset. That was probably an overstatement of several magnitudes. More likely, this was a one-in-a-hundred event, meaning you could see a sunset this great a few times a year.

I had been looking at satellite data that afternoon and saw a nice streak of high cirrus clouds moving across northern Arizona. The orientation of the clouds suggested that the sun might briefly appear below the clouds and illuminate the bottoms around and shortly after sunset.

Satellite image showing streak of cirrus clouds moving across northern Arizona.

So I headed out to Mormon Lake Overlook where there is a good view of the western sky and waited.

It worked out pretty well.

Comet C/2020 M3 (ATLAS)

November 13, 2020 / Add comment

A faint comet is currently moving through the sky in the constellation Orion. Unfortunately, it is too dim (mag. +8) to seen by the unaided eye but binoculars, a small telescope, or most digital cameras will be adequate to see it.

Comet C/2020 M3 (ATLAS) moving through the constellation Orion.

As the comet was moving near the belt of Orion I captured about one hours worth of exposures and then did the typical stacking using Deep Sky Stacker. Post processing was done with rnc-color-stretch.

The comet is located to the right and slightly below the belt of Orion. The future path of the comet can be found at in-the-sky.org.

Coyote Buttes and The Wave

October 19, 2020

My first and only visit to Coyote Buttes and The Wave was in June 2004. A coworker had permits for two back-to-back days but was unable to use them. The BLM permit system was quite different then from what it is now. Getting multiple-day permits was not unusual. Nowadays, getting a permit at all requires a fair bit of luck and perseverance. I consider myself fortunate to have had a chance to visit this amazing location.

We arrived at the trailhead in mid-day with temperatures, as I recall, in the upper ’90s. It was mid-June and the North American Monsoon and rainy season had not started. Even so, there were clouds and a few rain showers in the area.

We hiked out to the rocks and made good time arriving in the late afternoon. There were a few other visitors but they left after a short time and we had the place to ourselves for the next several hours. Really—there was no one else there. Hard to believe!

Clouds and showers develop around Coyote Buttes.

We wandered around for hours taking photographs and picnicking and enjoying the solitude. For a few brief moments, one of the rain showers produced a rainbow but I was too slow to move the camera gear and get the shot.

Clouds drift away and the sun returns in late afternoon at Coyote Buttes.

Afternoon sun makes shadows on the walls.

As the sun dropped in the west and temperatures began to cool we finally left and began the hike back to the car. Somewhere along the way we realized we were on a different trail—or perhaps no trail at all—but our starting point was still obvious and we continued on.

Late afternoon light illuminates the rocks on our hike out of Coyote Buttes.

The old sign showing trails to Coyote Buttes and Buckskin Gulch.

The next morning we decided we did not want or need to hike out there again so we did not use our 2nd day permit. Instead, we travelled down Buckskin Gulch—a place we had heard about but not yet had a chance to explore. It was a great hike and we did not regret our choice.

Here are photographs (shot on Fuji Provia slide film and recently scanned) from the afternoon that we spent at Coyote Buttes and The Wave.

Harvest Moon—October 2020

October 6, 2020

The nearly-full Harvest Moon rises above the Painted Desert and Wupatki National Monument. Two buttes on the eastern horizon (~80 km distant) are Montezuma’s Chair and Roundtop, remnants of ancient volcanoes.

The second image is a composite showing the path of the Moon as it rose above the two buttes.

Late afternoon sun on the Tloi Eechii Cliffs.

The third image is a view of the Tloi Eechii cliffs while we were waiting for the Moon to rise.

The photographs were taken from the Doney Mountain Picnic area and overlooking Wupatki National Monument and the Painted Desert.

Revisiting the Rho Ophiuchi cloud complex

September 25, 2020 / 2 Comments

Several years ago I took a sequence of images of the Rho Ophiuchi cloud complex and posted the result on these pages. As noted at the time I used a Nikon D700 paired with a Nikon 85mm ƒ/1.8 lens all mounted on an iOptron Sky Tracker. Images were stacked using Deep Sky Stacker and post processing was done using Photoshop CS6 and Astronomy Tools v1.6.

Since then I have been experimenting with different tools for postprocessing astro photos. Along the way I discovered some interesting software called rnc-color-stretch from Clarkvision.com.

The rnc-color-stretch algorithm does 3 main things. 1) Analyze the image histogram to maintain a black point or use set low level color throughout the stretching process. The histogram is analyzed at multiple stages from beginning to end. 2) A power stretch while maintaining the black point. 3) Recover lost color after the stretching process. How far you can stretch an image depends on the signal-to-noise ratio.

I’ve been testing this software on both recent and older images. I thought it might be interesting to try it on the Rho Ophiuchi images taken in 2015. Once again, I used Deep Sky Stacker to register and align the images. Then I ran rnc-color-stretch. The result is the image shown above. I thnk it did a fine job of pulling out the details and the color.