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Visitors, Crescent Venus, Crescent Moon,
61 Cygni Proper Motion

Posted: 22 July 2015

Before I opened the observatory, I saw this Lesser Goldfinch who came for a visit:


Open: Tuesday, 21 July 2015, 1829 MST
Temperature: 98°F
Session: 849
Conditions: Partly cloudy, breezy

1838 MST: viewed Venus, 83X. Then set up to image Venus using the D7200 DSLR. Mounted the camera at prime focus + 2X PowerMate and did some 15 seconds HD video recordings, 1.3X crop factor, 60 fps, ISO 400. This is a stack of 936 frames, 1/400sec:


1846 MST: switched to the Baader 8-24mm Zoom Eyepiece. The view of Venus was really nice at 250X. Then viewed Jupiter. 1852 MST: returned to Venus but thin clouds were now messing up the view. I was expecting some (people) visitors so hoped that the sky conditions would cooperate. 1922 MST: Venus was now an easy naked eye object before sunset. 1932 MST: sunset.

Slewed to the crescent Moon and viewed it at 83X. Mounted the D7200 DSLR at prime focus for this image through thin clouds, 1/400sec, ISO 640:


1939 MST: my guests arrived. They brought their new Celestron 4.5" Newtonian reflector on a non-computerized German Equatorial Mount in order for me to check it out and provide some basic instruction on its use. I first let them look through my Meade 8" LX200-ACF in the observatory. Showed them Venus, Jupiter, the Moon, and finally Saturn. 2009 MST: we set up their telescope on the observatory patio and I began checking it out. I explained how to set up the tripod for proper polar alignment and how to use the Right Ascension and Declination slow-motion controls. The red-dot finderscope had a couple of issues: it would not focus nor did its adjustment have enough travel to optically center the red dot when the main telescope was on an object. But we worked through those issues and viewed the Moon and Saturn through the Newtonian telescope. 2125 MST: having finished with the telescope initial set up and operation, my visitors left. Glad the clouds mostly cooperated during their visit.

Unfortunately, the clouds were now in much of the sky at this point. The constellation of Cygnus was only partially obscured by thin clouds so I decided to try to image the nearby (11.4 Light Years away) double star 61 Cygni. I had imaged it one year ago (21 July 2014) and I was hoping to show the stars proper motion over the past year. I powered on the GC Wi-Fi Adapter and used SkySafari Pro to GOTO 61 Cygni. I compared the view (through thin clouds) at 83X with the image from 2014 and I could see that the double star system had moved a little further away from a faint more distant star. I set up to image 61 Cygni. Mounted the D7200 DSLR at prime focus + 2X PowerMate. Did a focus test on the star Deneb using the Bahtinov Mask and then slewed back to 61 Cygni. The double star was visible in the camera viewfinder. I continued to monitor the clouds in Cygnus and decided the conditions were not improving. At 2150 MST I took this image through thin clouds, 5 seconds, ISO 1600:


During post-processing I combined the image from 21 July 2014 with the image from 21 July 2015. This animated GIF shows the proper motion of 61 Cygni in one year:


Notice the movement of the double star 61 Cygni away from the close faint star. The "movement" of the other stars in the frame is due to changing cameras during the year. I used a D7000 in 2014 and the D7200 in 2015.

2152 MST: ended imaging. Unfortunately, thicker clouds now covered most of the southern sky. I had planned to do a confirming iPhone image of Pluto to compare to the image taken on the previous session. I checked a satellite image and could see that more extensive clouds were on the way from Mexico. Decided to give up for the night.

Close: Tuesday, 21 July 2015, 2220 MST
Temperature: 78°F
Session Length: 03h 51m
Conditions: Mostly cloudy

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