Holiday Sunset Alignment!

It is that time of year again - if we are nearing the winter solstice and the holidays are upon us, it is time once again to travel up the Mount Lemmon Highway to once again document the sunset alignment against Kitt Peak National Observatory. I feel like an astronomer of old, looking for alignments to tell the turning of the seasons, and indeed this is true. From "my spot" (about milepost 8.7) along the Mt Lemmon Highway, the alignment is nearly perfect when the sun hits a declination of -23 degrees, 24 minutes which happens on the sunsets of the 18th and 24th this year. All of the telescope domes atop the mountain will fall within the observed disk of the sun.

This year we had 3 other TAAA members observing with us. Meeting at the base of the mountain at McDonalds at 3:30, it was a 30 minute drive up to the spot, providing plenty of time to set up equipment. This year, rather than take still images every few seconds and turn them into a movie like last year, we decided to use Melinda's T1i to take HD video - duh! It should look much nicer, and at 30 frames a second, with sound besides, it should be the ultimate reproduction of the sunset. Besides Melinda's Canon T1i, I also used the Celestron 5 I got from Elinor and David Levine - it provides the perfect image scale for the moon or sun to just fill the short axis of the APS-C sensor. I practiced using the video mode the night before on the moon, and freshly collimated on a star to provide the sharpest images.

While the alignment has been reduced to a science (no question anymore of a perfect alignment), the weather conditions were questionable even as we met at the base of the hill. High clouds were gathering and they looked even thicker towards the west, but we were all motivated to try, so off we went. After setup, focus and alignment, we got to gather, offer advice and guidance as "magic time" came. It appeared luck was with us as a clear strip appeared over the mountain, from our vantage point at least, 60 miles away. As the sun moved ever closer to the horizon, it finally came into the telescope's field of view and I pushed the "record" button. I was anxious as a cat near a rocking chair, but the image on the camera screen looked just about perfect. After the sun disappeared behind the 90" telescope, I removed the solar filter and recorded the sunset colors for a couple more minutes. In all, we got nearly 9 minutes of video, recorded at the medium-HD resolution. Still, it is about 1.4GB, so impossible to display on the blog at anything approaching full resolution - we'll have to see how we can display it publicly. Shown here are a few frames pulled from the video... It was fun gathering around and watching the replay. Playback at normal speed with the sound is quite fun, approaching the anticipation of even a total solar eclipse as it progresses!  {We have uploaded the video to YouTube.com.  If you click on this link "Mt. Lemmon/Kitt Peak Sunset" you will be able to watch it!  Remember, it is a huge file and if you have a slow internet connection it may take a very long time.}


But the fireworks were not quite over. Even well after the sun had gone down, the western sky was ablaze with color and shifting clouds. This was, without a doubt, the most amazing, dynamic sunset I've seen. Cloud patterns and colors shifted minute to minute and it seemed to go on for much longer than most colorful sunsets. Just amazing! And for dessert, we stopped on the trip down the hill at one of the overlooks showing the city lights, Kitt Peak far in the distance (the flat-topped mountain on the horizon). We continued on to a holiday party at my boss', but what we had just witnessed will stay with us for a long time!