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Dry Run for upcoming Transit of Mercury

Posted: 7 May 2016

Wind and clouds returned on Wednesday, 4 May 2016, and continued through Thursday, 5 May. Following the Oracle Dark Skies Committee (ODSC) meeting on Thursday I took photographs of a local Circle K store that had upgraded its pump area lighting to be night sky friendly at the request of the ODSC. The difference is dramatic, as seen in these before and after photos:


Thank you to Circle K for supporting the local community and Oracle State Park, an IDA "International Dark Sky Park"!

At the ODSC meeting a new Oracle State Park gift shop item was shown by Park Ranger Redies:


It is a magnet with my photo of "Star Trails over Kannally Ranch House, Oracle State Park". They also have a postcard available in the gift shop with the same photo. Thanks to Arizona State Parks for highlighting Oracle State Park with these.

Friday, 6 May, continued the partly cloudy sky and with winds too strong to open the observatory. Saturday, 7 May, began partly cloudy and calm, giving me an opportunity to do a short dry run in preparation for Monday's Transit of Mercury.

Open: Saturday, 7 May 2016, 0808 MST
Temperature: 59°F
Session: 956
Conditions: Partly cloudy

Equipment Used:
12" f/8 LX600 w/StarLock
Wireless AutoStar II handset
2" 24mm UWA eyepiece

D7200 DSLR

StarLock OFF. Used OPT 2" star diagonal and Thousand Oaks Optical Solar Filter. Did a GOTO "Sun as Asteroid". 0821 MST: viewed the Sun, 102X. Two sunspots were visible. Then began setting up for DSLR imaging of the Sun.

Mounted the D7200 DSLR at prime focus + visual back. The entire solar disk was not in the camera field-of-view (FOV). Added the Optec Lepus 0.62X Focal Reducer. That allowed the entire solar disk to fit in the FOV, but just barely. I then began a series of test exposures at various shutter speeds and ISO values, White Balance Auto. Focusing was difficult due to bright sunlight in the observatory and clouds in front of the Sun at times. I will probably use my "black head cover" for focusing for the actual transit event.

This is a 1/1000sec, ISO 100, exposure:

Mouseover or tap on image for sunspot labels
Mouseover or tap on image for sunspot labels

0846 MST: last look at the Sun, 102X. Weather permitting, I am ready for the Transit of Mercury. The Sun will rise at Cassiopeia Observatory with the transit already in progress Monday morning, 9 May.

I then did some measurements from the pier to the POD wall. I had previously measured the "rolling space" between the tripod and wall when I had the 8" LX200-ACF. Now I needed new measurements for the pier. The minimum clear rolling space is 27", except by the electrical outlets on the floor where it is 26". I will need these measurements if I ever find a suitable observing chair on wheels.

Close: Saturday, 7 May 2016, 0903 MST
Temperature: 70°F
Session Length: 0h 55m
Conditions: Partly cloudy

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