Sunday, November 25, 2018

Chiricahua Bound!

Have been back at "Ketelsen West" for nearly a month now... Still suffer from lack of inspiration to blog, though I've got loads to put up! Case in point is this trip to Chiricahua National Monument, that I visited 2 weeks ago now! My friend Laurie needled me to get out and observe that Saturday evening and since the Chiricahuas are a favorite of us both, we hit the road early afternoon for the 2 hour trip.

We got there a little before sunset, and drove up "Rhyolite Canyon" along some beautiful scenery. Fall colors were a little past peak among the sycamores along the canyon bottom, but still the rock formations formed of compressed ash from a long-extinct volcano were quite spectacular! Rock formations at left, and that is Laurie at right...


I hustled to set up the mount at Echo
Canyon parking lot - the plan was to mount the 500mm Canon camera lens to do some astrophotography for part of the night. Once set up, we both adjourned to Massai Point a half mile south for another project. I've always had a "thing" for the rock formation 5 miles to the north - the perfect profile of the Indian chief Cochise. While I've shot it many times before during the day, I was hoping to use the 4-day old moon's illumination to make it stand out a bit in the dark. At left is a shot right about sunset. Then after aligning the mount to Polaris and taking some sky flats, I returned to shoot Cochise with stars wheeling overhead. I found out that the moon was way too dim to even assist with locating the rock formation in the dark! I persevered and managed to take a passable frame.


Returning to Echo Canyon, Laurie worked on some wide-field shots of the sky, and I took three series of exposures on 3 objects of interest (to me, anyway!). First up was a dark nebula along the Milky Way in the constellation Cepheus. Shown at left, the dark nebula is known as the Seahorse Nebula, from its distinctive shape. Its catalog name is Barnard 150.  Also at left is a spiral galaxy NGC 6946, unusual for being located so near the Milky Way. It is relatively bright, and only 23 million light years distant - relatively close! And not to be forgotten, at lower left is a star cluster, NGC 6939, well within our own galaxy, a mere 4,000 light years distant.  This frame is about an hour of stacked exposures with the 500mm lens and like all exposures here, north is up.

The next object was a "bright" comet, almost directly overhead. If it wasn't so close to Beta Andromeda (itself a guidepost to finding the Andromeda Galaxy) it might be harder to find. But being just north of Beta, I just put the bright star in the lower edge of the field and shot away - there it was, glowing green! This comet is 64P Swift-Gehrels, making a close appearance to the earth - only 43 million miles from the earth, and 130 million miles from the sun (the earth is about 93 million miles from the sun). The green glow is caused by solar radiation dissociating carbon molecules from the comet's nucleus, which glows green in the vacuum of space... The sharp-eyed among you might note a fuzzy spot just upper left from Beta Andromeda at the lower edge. That is NGC 404, long a test object to see if your telescope reveals it so close to a bright star. This is 10.5 minutes of stacked exposures.


My last object for the night was a pair of "bright" nebula (as opposed to dark, seen by silhouette), also adjacent to a bright star. In this case, the bright star is Gamma Cassiopeia - the bright "W" currently on its side in the northeastern sky. Gamma is the center star of the "W", and the photo at left reveals some diffuse glows near it. The intense radiation of the star excites the gas to glow by fluorescence, as well as the radiation pressure pushing back the gas to form "sharp" formations pointed towards the star. I've seen photos of these (IC 63 and IC 59 left and right) thru big telescopes, but didn't know if it was possible in a "mere" telephoto lens.  This is 16 minutes of stacked exposures...

With the early sunset, we got in all the above observing, packed up and hit the road for the Tucson return about 10:30, hitting home about 12:30 - a productive night for the limited time on-sky!

Addendum!
I asked Laurie to send along her photo of
the wide-field shot of comet 65P Swift-Gehrels that also included the Andromeda Galaxy. Shown at left is a stack of 6 frames of 4 minutes total exposure taken with her T3i APS sensor camera with my 200mm lens. Please ignore the magenta halos around stars - they can sometimes be removed by adjusting focus slightly, but harder to remove in post-processing!

And at left is a labeled version - north is approximately at upper left... Note how obviously the greenish tint of the comet makes it so apparent! Unfortunately, it doesn't work when finding it visually as our eyes aren't sensitive enough to see colors on faint objects!

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