Thursday, April 17, 2014

Mexican Lunar Eclipse!

We just got back from a short trip down to Puerto Peñasco  to visit our friend Margie at her home there, view the lunar eclipse Monday, and just relax a couple days.  We were out of cell range and lacked internet access, so have been out of touch for most of the week.  We left early enough on Monday (mid-morning for the 4-hour drive) to get settled in well before sunset.  Watching from her "astronomy deck" on the roof, we had a great view of moonrise over other houses and condos down the beach a few minutes before sunset.  I was hoping to get a time-lapse of the moon rising over the Sea of Cortez, but it rose too far to the north and the sky was hazy enough it would have been tough - plus I was late and didn't see it in time.  Sharp-eyed Melinda was first to spot it.  This shot at left is a 4-frame mosaic with the William Optics 11cm F/7 telescope (770mm focal length).

While I didn't capture it, the moon was sitting just above the "Belt of Venus", the shadow of the earth rising into the eastern sky.  It was quite spectacular as the sky darkened.  Watching the moon rise in the telescope (I swapped between eyepiece and camera on the W.O. scope most of the night), we were also able to observe "notches" in the edge of the moon from it rising through temperature layers in the atmosphere.  Also interesting as the moon neared the earth's shadow was that there were absolutely NO shadows visible around the edge of the moon.  Normally, even near full phase, the sun isn't directly behind us and one edge of the moon usually shows some crater's shadows.  But not this time.  At left is the moon shortly before the eclipse started, so shows the moon as full as it can get outside of eclipse.  At right, about an hour later, the penumbral phase of the eclipse had started, and the partial shading of the earth's shadow was spotted.

Finally, right on time about 11pm local time, the hard edge of the earth's shadow touched the moon and started its march across the moon's disk.  While it looks similar to crescent phases of the moon we see during the month, notice there are no crater shadows available.  During a lunar eclipse such as this, the dark edge is caused by the earth's shadow, not the phase of the moon!

As a smaller and smaller part of the moon was illuminated, the stars started to come out, yet, the camera exposures needed to stay short to keep from overexposing the moon still in sunlight.  It wasn't until a full hour after the shadow first contacted the moon that it was fully engulfed, and no longer illuminated by direct sunlight.  The photo at right was taken  3 minutes before totality and I could expose long enough (1/4 second) to start showing the red illumination caused by light refracted into the earth's shadow by our atmosphere.  The blue rim inside the earth's shadow is evidently real, explained as an effect of ozone in the upper atmosphere of earth.  The star shown at the upper left corner is 76 Virginis, bright enough to show up on many shots of totality.

Finally with the moon entirely within the earth's shadow, we reveled in the dim orange orb of the moon, only slightly brighter than the orange spot of Mars a few degrees to the west.  Shown at left with the wider view of the 70-200 zoom (set to 80mm), the moon is shown with the bright blue Spica to its lower right, and orange Mars to upper right.  It was quite amazing to see the clouds of the Summer Milky Way rising in the east with the ruddy eclipsed moon to our due south.  The view through the telescope had a 3D effect with stars visible around the moon - a rare sight since it normally drowns out any stars in the field.  Because I didn't have a tracking mount for the telescope, I was limited to exposures of about a half second before trailing became objectionable.  In fact, we had a bit of a blustery wind during all phases of the eclipse, so I had to go to a bit of trouble for all the totality images.  The shot at right is one of these half-second exposures and is about my best shot.  Taken right at mid-totality at 1245, you can tell from the illumination that the moon passed south of the earth's shadow center.  Next time I'll set up with a sturdy tracking mount in a dark site, but this one, spent with friends at an exotic location made it a special event too.

Like our Christmas trip, I've got lots of posts waiting for me in the 1500+ pictures taken this trip.  Stay tunes for some interesting stuff!

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