Open: Wednesday, 1 April 2015, 1815 MST Temperature: 82°F

Session: 803 Conditions: Mostly clear, breezy

I set up my Meade ETX-70AT refractor telescope on the observatory patio to do a test of Twitter Periscope Livestreaming. I wanted to know how well the ETX-70 would work for livestreaming in case I decided to use it to livestream Saturday's Total Lunar Eclipse. Here's the ETX-70 in front of the SkyShed POD 20 minutes before sunset:

1831 MST: viewed Venus, 83X, in 8" LX200-ACF. Then viewed Jupiter, 83X. Ganymede, Io, and Europa were visible. Callisto was not yet visible against bright blue sky. Europa would occult Io beginning at 184144 MST. This was not a large magnitude change occultation so decided to observe it instead of imaging it. Switched to 222X. 1836 MST: Callisto was now visible. Seeing was not very goood, however, during the 4.4 minute occulation of Io by Europa I could see that the combined object was slightly elongated from the slightly off-center occultation. The combined object was noticeably brighter than either moon was when they were separated.

1850 MST: viewed the waxing gibbous Moon in the 8" LX200-ACF, 83X. Took this handheld iPhone 5s afocal full-frame photo, 83X:

1857 MST: began using the ETX-70AT. I first did an Easy Align using the AutoStar #494. Both alignment stars were in the 25mm eyepiece (14X) field-of-view (FOV) on initial pointing. I then did a GOTO the Moon, which was placed in the FOV. Switched to a 26mm eyepiece with the MX-1 Afocal Adapter. This full-frame iPhone 5s photograph shows how the Moon appeared at 13X magnification with the 26mm eyepiece (no Moon Filter, but did use Camera app exposure control):

Switched to a 9mm eyepiece (39X) but needed to add a Moon Filter to keep the Periscope iOS app from way overexposing the Moon. This full-frame iPhone 5s Camera app photo (with Moon Filter) shows a better view of the Moon:

I then livestreamed the view of the Moon through the ETX-70AT refractor telescope. The Periscope app still had some overexposing. I tried using various digital zooms to get the best view of the Moon during the 8 minute livestream. Here's one frame from the Periscope video with some digital zoom applied:

1931 MST: ended the ETX-70AT livestream. Weather permitting I plan to try livestreaming from my ETX-90RA Maksutov-Cassegrain telescope on Thursday evening.

Returned to the 8" telescope and did some lunar observing, 222X.

During the daytime I came to realize that I had never measured the actual FOV of my Celestron Cometron 12x70 Binoculars. So this night I did a measurement. The stars Mizar and Alioth in the handle of the Big Dipper fit almost exactly diametrically opposite each other at the edge of the FOV of the 12x70 binoculars. I then used SkySafari Pro on the iPhone 5s to measure the distance between these stars. It reported the 12x70 binoculars FOV as 4°21'41.6". So now I know.

Close: Wednesday, 1 April 2015, 2025 MST Temperature: 64°F

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