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Oracle State Park: Sky Quality Measurements #2

Posted: 3 May 2014

After several days and nights of dust filled skies due to strong winds, the dust was mostly gone by Friday, 2 May 2014. I returned to Oracle State Park to do more Sky Quality Measurements (SQM) and sky photos to support the Park's IDA "International Dark Sky Park" nomination. I arrived at the Park at 2210 MST. Moonset was at 2218 MST. After taking SQM readings using the Unihedron SQM-L meter at the Arizona Trail Walk-In parking lot and the Group Use Area, I set up a Meade ETX-125AT telescope, observing chair, and a Nikon D7000 DSLR with Rokinon 8mm 180° Fisheye Lens on a Meade LXD55 GEM tripod at the Kannally Ranch House parking lot. This was the setup:


When not taking SQM readings, I observed a few objects to check the observing conditions at the Park. Although there was still some dust in the air from the recent strong winds (which also affected the SQM readings), viewing was pretty good. I viewed the Ring Nebula (M57), the Great Globular Star Cluster in Hercules (M13), Mars, and Saturn. I also did some slo-mo (120 fps) video recordings (5 seconds) through the ETX-125AT using an Apple iPhone 5s. The video frames were stacked using software to yield the following images.

Mars, magnification 392X, 459 frames stacked:

Saturn, magnification 392X, 516 frames stacked:

The Mars image shows the North Polar Cap (small white spot at the top), the large dark area called "Syrtis Major" (triangle shape at bottom), and even some clouds (bottom and left edge). Not too bad for a small portable telescope. The Saturn image shows some faint cloud bands as well as the Ring. Cassini Division in the Ring is blurred out as Saturn was still low in the sky at the time of the imaging.

Shortly after midnight the Milky Way had risen high enough in the east to begin photographing it. This is an f/8, 5 minute, ISO 2500, fisheye lens photo, using the tracking LXD55 mount:


The darkest sky SQM reading I obtained this night was at 0100 MST at the Kannally Ranch House parking lot. It was 21.42. My previous Oracle State Park: Sky Quality Measurements report has some information on SQM and a conversion chart to star magnitudes.

I left the Park at 0105 MST, Saturday morning.

After spending time at Oracle State Park on Friday night and very early Saturday morning, and after getting a few hours of sleep, I went to the "San Pedro Riverfest" in Winkelman, Arizona:


This photo shows where exhibitor tables were set up:


I represented the Oracle Dark Skies Committee at the Oracle State Park table and did some public outreach on the importance of preserving Arizona's natural resources, which includes the night sky. Here you can see Park Ranger Dale (right) and me (left) at our table:


The Riverfest was well attended and many county residents, business owners, and elected officials stopped by to ask about the Park and to tell us how much they appreciated our Dark Skies effort. Our day at Riverfest was definitely worthwhile.

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