Sunday, January 13, 2013

(Yawn) Another Sunset Trip...

After today's cheap movie matinee (Les Misérables ), we exited to continued cold temps, but blue sky, so we decided to take a little sunset trip to Babad Do'ag Overlook (shortened to "Bad Dog" to those familiar with it!) near milepost 3 on the Mount Lemmon Highway.  I've been sort-of looking to figure out the date that the sun sets behind Kitt Peak from this alternate location, which broadens the Solstice-only observations from 6 miles further up the mountain road.  A check a week ago indicated it would be this week, so we went for another data point tonight.

With the lower elevation and later sunset, we didn't leave till an hour before sunset, but we still had plenty of time to set up the William Optics APO I posted about 10 days ago.  And sure enough, more pictures with which to take some measurements, shown at left.  While it missed the Observatory, it did catch the solar scopes on part of it's trip to the horizon.  Apparent also are some really nice sunspot groups, even though viewing right over the horizon is not optimum.  Sure enough, the alignment is this week, Wednesday the 16th if my calculations are correct and anyone is interested...  Unfortunately, the problem with this later alignment is that the sun moves a considerable amount from day to day, so only this one chance!  By my calculation, the needed solar declination is -20.788 degrees, Wednesdays is -20.796.  Not sure if I can get away on Wednesday, we'll see.

There were some other great items to image.  Across the valley is a nice antenna array that makes a nice, high-contrast object upon which to focus.  I believe several FM stations broadcast from this peak in the Tucson Mountains, shown at left.  At right is a view of the cubical-shaped Multiple Mirror Observatory about 45 miles south our observing spot atop Mount Hopkins.

A little after sunset the Moon that was such a sliver yesterday was quite visible.  And since it washigher in the sky than yesterday, the "earthshine" became visible after it got a little darker.  This "old Moon in the new moon's arms" is actually from the earth!  The phase of the Earth, as seen from the Moon is complementary - in other words, if the moon is new, near the sun, the Earth would be fully illuminated and extremely bright, resulting in the "dark side" of the Moon being visible.  At left, a short exposure shows craters down to the maximum resolution of the camera and telescope (shown at nearly full camera resolution).  At right, with an exposure of nearly a second, the crescent is purposefully overexposed to show details revealed by the earthshine.  Since I wasn't tracking, the Earth's rotation blurred the moon slightly, but not enough to degrade the shot too much.

And of course, high in the eastern sky was Jupiter.  An exposure of just .1 second overexposed the disk of the giant planet, but revealed the 4 Galilean moons.  From lower left are outermost Callisto, Europa, innermost Io, and on the right side of the disk is Ganymede.  This shot is displayed at full camera resolution, and while the 770mm focal length of the telescope doesn't show a lot of detail in this tripod shot, it is fun to see what you can get with the snapshots we're showing here...

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