Cassiopeia Observatory - Report - Ceres and Vesta Conjunction

Ceres and Vesta Conjunction

Posted: 3 July 2014

I opened the observatory with the hope of imaging Ceres and Vesta as they approach their close conjunction on 4-5 July 2014. I had previously imaged them together on 29 June and 30 June. See those reports for the images and animations. This night would be hampered by the clouds.

1939 MST: sunset. Took this photo of the western sky at 1943 MST. The observatory is at the lower right and the crescent moon at the upper left.

1945 MST: did some brief lunar observing, 83X. Clouds were near the moon. Grabbed this handheld iPhone 5s afocal 83X photo (slightly cropped):

1954 MST: quick look at Mars, 83X and 222X. Seeing bad (clouds) but there was a hint of a dark area visible. Then viewed Saturn, 222X. Clouds were affecting the view but the moon Titan was visible.

1959 MST: slewed to Spica to begin preparations for observing and imaging the Ceres and Vesta conjunction. Began closely monitoring the clouds. 2022 MST: powered on the GC Wi-Fi Adapter and used SkySafari Pro 4 to GOTO Ceres and Vesta. Both asteroids were visible well inside the 2" 24mm UWA eyepiece (83X) field-of-view. Set up for imaging by mounting the D7000 DSLR at prime focus of the 8" LX200-ACF. Some thin clouds were now covering the area. Did a focus test image on the star Spica using a Bahtinov Mask.

Slewed back to Vesta. Both asteroids were visible in the camera viewfinder. Began imaging at 2035 MST, 30 seconds, ISO 1600. I did exposures every 15 minutes for one hour. 2040 MST: a band of thick clouds was approaching the asteroids. 2049 MST: began seeing lightning flashes from a distant monsoon thunderstorm in the southeast. 2110 MST: thick clouds were now almost at the position of the asteroids. 2112 MST: asteroids now appeared fuzzy in the viewfinder due to clouds. 2113 MST: Ceres gone, Vesta almost gone. 2114 MST: nothing visible in camera viewfinder. 2120 MST: still nothing visible in viewfinder. Thick clouds were in most of the sky; even the moon was hidden behind clouds. 2133 MST: the asteroids briefly appeared in the viewfinder but then rapidly disappeared again. 2135 MST: took my final image. Unmounted the camera and got a quick look at the asteroids, 83X, as they briefly popped into view.

The final two images had nothing. So this night I was only able to cover 30 minutes of motion by the asteroids. The image below shows Ceres and Vesta:

Began closing the observatory. Due to forecast monsoon storms for the next few days and nights, may not be able to get the closest conjunction (10 arcminutes) on 4-5 July.

For those who can't resist seeing and hearing me, here's a five minute video clip (76 MB) from the 2 July 2014 Pinal County, Arizona, Board of Supervisors meeting discussing a "Letter of Support" for the Oracle State Park "International Dark Sky Park" designation:

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