Monday, December 7, 2015

A Less Than Optimal Alignment!

While the dry desert southwest is supposed to have long stretches of clear weather, sometimes you can't get a break! Case in point is this morning's occultation of Venus by the Moon, where the disk of the Moon approaches and blocks the brilliant disk of Venus for North America. Their celestial motions can be predicted years, even centuries in advance, but even as you set your alarm to rise before dawn, you might well be looking at the bottoms of clouds in the morning.

Such was the case this morning. Plans were made, equipment was collected and set up last night so I wouldn't have to make decisions at a time I'd normally not be awake. But when stepping outside at 4:30 to assess the situation - nothing but clouds! Oh wait - there was a spec - a much extincted spot of Jupiter was the only thing visible. I went back to bed for another hour, then rose to look again. Much better - definitely some clouds, but a chance to catch at least the pair as they converged for their close-up. At left is a 10th second exposure with a 300mm lens. The moon is shining thru some clouds, with Venus to its lower left. The clouds were quite variable, never clearing, but sometimes so thick that Venus all but disappeared. Tough to give up all together - I had to hang out and wait to see what would happen...

Well, the reward for clouds is that you can often get a spectacular sunrise or sunset, and as dawn approached, the reds and oranges of a pretty sunrise was at least some payment! For the peak of the color, the Moon/Venus pair disappeared behind the thickest cloud. Fortunately, the clouds moved fast enough to catch the pair before the color faded. The image at left was taken with the kit lens set to 30mm, hand-held at 1/8 second. And shortly after that image was taken, a nearly clear spot moved in and I hustled to grab some frames with the Meade 80mm F/6 (480mm focal length) which framed the pair nicely and still easily fitting Venus in the view.

Unfortunately, as the sun rose, the clouds lit up a dull grey and the Moon/Venus pair disappeared. The occultation, where the Moon passes in front of Venus is still an hour away, but with the sun above the horizon, it will be impossible to see unless it is nearly clear. I already gave my notice I'd be late to work, so will hang out at home, but it is looking pretty hopeless. At least the pair against the dawn was a pretty catch - maybe even worth losing a couple hours of sleep!

Epilogue - Well, I got something! Even though it looked pretty hopeless 30 minutes before the Moon was scheduled to cover (occult) Venus, I set up the TEC 140 scope to equilibrate a bit when some blue-ish sky was seen towards the west. While doing other Monday morning chores (cat feeding, garbage to curb) I decided to give it a try and of course, was rushing like a madman to the end. Camera on scope, focus on distant pole, grab binoculars to try to find the Moon (was not using a tracking mount) which was tough in a partly cloudy sky. Finally spotted it right on the meridian in binoculars with a brilliant jewel adjacent to it. Swung up the scope and tried to use live view to focus - a disaster in the bright daytime. A quick look through the camera and I got a better view than through the binoculars, so pushed the button for two quick exposures, adjusted a stop or two between them on the shutter. Returned to live view and never saw anything to focus on. Another glance in the camera and the jewel was gone - the planet blocked by the Moon. Carried the camera in, hoping I got something and I'd say it is something. Not critically focused, but the bright jewel of Venus a couple seconds before moving behind the limb of the moon. I consider myself lucky to get anything with the clouds and the difficulty they added. Perhaps not spectacular enough to make the annual highlights, but a real adventure nonetheless!

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