Thursday, January 9, 2014

Countdown to Conjunction!

Two days to Venus' inferior conjunction when it is closest to the Sun!  Fortunately, it passes about 5 degrees north of the Sun this time as opposed to actually transiting the Sun's disk last time...  The extra few degrees makes it easier to spot in twilight too - I was able to spot it tonight when thick clouds cleared late in the day!  I again observed from our cul-de-sac's mailbox where I'd spotted it recently, this time I set up the William Optics 11cm F/7 triplet refractor, so effectively a 770mm lens.  Melinda took a snapshot of me as I was taking a couple images - mounted to a tripod where I used a timer to take pictures vibration free - using mirror lockup and a 2 second delay to minimize shaking from the mirror.  I like to have the tripod set to my height to minimize discomfort when doing observations like this. 

I first spotted it in binoculars - it wasn't until the sun dropped below the Tucson Mountains before the sky dimmed enough to spot it, but once seen, it was pretty easy to see in binocs and telescope, though I forgot to look for a naked-eye view!  Tonight's image is shown at right, and is shown at full camera resolution.  With the crescent as low as it was, it is not a great image, but it is what it is!  Turns out it was taken right at the moment of actual sunset at 5:37 local time.  I've got plans for tomorrow night, but may well try to shoot Venus again at high noon on Saturday, the day of inferior conjunction.  I've observed Venus during inferior conjunction before, but with a go-to scope.  With the 5 degree separation it should be easy to set up in the shade of a building to do the observation on conjunction day.  Watch this space!

With the waxing gibbous moon in the sky, it was easy to take a snapshot for a comparison of size.  The image of the moon is at the exact same scale as the Venus shot above.  Venus appears to be about the size of some of the above-average craters...

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