Open: Sunday, 17 May 2015, 1812 MST Temperature: 85°F

Session: 821 Conditions: Mostly clear, some clouds in east

As I arrived at the observatory, this visitor was there:

1820 MST: viewed Venus, 83X and 222X. Nice view at 222X. Mounted the iPhone 5s on the 8" LX200-ACF telescope using the MX-1 Afocal Adapter. This is a stack of 1153 slo-mo frames (10 seconds, 120 fps, Keith's Image Stacker) afocal 231X:

1837 MST: removed the MX-1 and iPhone, switched back to 83X, and tried to observe Mercury. No joy. 1842 MST: Mercury's thin crescent was now visible, 83X, although it was very difficult to see against the still bright sky 38 minutes before sunset. Switched to the MX-1 and 231X, but could not see Mercury. Did several slews between Venus (for focusing) and Mercury, but still no joy on Mercury at 231X. 1920 MST: sunset. 1926 MST: finally picked up Mercury, 231X. It was not visible in the 7x50 finderscope though. This is a stack of 1135 slo-mo frames, afocal 231X, taken at 1932 MST:

1936 MST: removed the MX-1 and iPhone and viewed Mercury, 222X. Nice crescent, but Mercury was about to get into the tree west of the observatory. Mercury was just becoming visible in the finderscope. 1938 MST: Mercury now into the tree.

1945 MST: slewed to M104 (Sombrero Galaxy), which would be my first DSO target for the night. Prepared the D7200 DSLR for DSO imaging. Astronomical Twilight would end at 2050 MST this night. 2007 MST: M104 easily seen at 83X. 2011 MST: slewed to Spica, which would be the focus test image star and SYNCed the AutoStar. Mounted the D7200 at prime focus + extension + off-axis guider and did the focus test image using the Bahtinov Mask. 2038 MST: slewed to M104 and began searching for a guide star, but found none. Tried a 2 minute unguided exposure but it trailed. I then did 15 unguided 1 minute, ISO 12800, exposures. Only 8 images were untrailed. This is an unedited 1 minute, ISO 12800, image of M104:

And this is a stack of 8 1-minute, ISO 12800, images using Lynkeos of M104 (Sombrero Galaxy):

2110 MST: slewed to Centaurus A (galaxy) and found a guide star. After doing a 1 minute, ISO 12800, unguided framing test exposure, I did 10 2-minute, ISO 12800, guided exposures. This is one of the images, unedited:

And this is a stack, effective exposure 20 minutes:

2143 MST: ended DSO imaging. Began setting up to image Saturn at prime focus + 2X PowerMate. Did a focus test using the Bahtinov Mask. I then did several HD video recordings, 1.3X crop factor, 60 fps, using various exposure settings. This is a stack (Keith's Image Stacker) of 1845 frames (30 seconds), 1/100sec, ISO 6400, with poor seeing conditions:

I then did some test exposures at various exposure settings to capture some of Saturn's moons. This composite image (Saturn at 1/30sec, ISO 1600, and the moons at 1 second, ISO 12800) shows four moons (Titan, Rhea, Tethys, and Dione):

This screen shot from the iOS app Gas Giants (free) shows the configuration of the moons:

2217 MST: ended Saturn imaging. 2224 MST: viewed Saturn, 222X. Seeing was pretty bad; could hardly see Cassini Division. View at 83X was not good either. Could see the fours moons captured in the image as well as the moon Iapetus.

Then viewed Omega Centauri (globular cluster), 83X. Due to the poor seeing decided to close up for the night.

Close: Sunday, 17 May 2015, 2246 MST Temperature: 61°F

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