Tuesday, September 14, 2010

Arizona After Dark!

We're just past the last dark-of-the-moon, the best time for amateur astronomers to get out under dark skies and not have to worry about light pollution caused by the moon. We've only got to deal with man-made light pollution! This last Friday, Melinda and I went up to Kitt Peak to try to image an Iridium Flare that would appear over the 4-meter telescope.

While we had the best of intentions to arrive early and set up, rush hour traffic conspired against us and I opened the shutter seconds after the peak brightness. Clicking on the image and looking above the 4-meter dome, you can see the fading streak of the satellite, not nearly the -7 magnitude predicted.

While we were up at the mountaintop, we took a few snapshots of the domes there. Since I work for Steward Observatory, I stayed close to their section of the mountain, since I'd not gotten permission from Kitt Peak to roam over their area. In the deepening twilight, brilliant rising Jupiter dominated the eastern sky with the lights of Tucson and rising fall constellations. Included here is the straight shot, then an annotated image is enclosed to point out some things to look for. Tucson has grown mightily the 5 decades since the observatory was founded, but Phoenix to the north has a bigger sky glow than closer Tucson.

Just up the hill a bit from where we parked to the south is the historic 36" Spacewatch Telescope. This telescope was originally housed on the University of Arizona Campus in the '20s, and was relocated to the darker skies of Kitt Peak in 1962. Since the 80s, it has been utilized by the Spacewatch Project to look for near-earth asteroids and comets. The program, now expanded to a nearby 72", has been very successful. We took the opportunity to shoot our Milky Way galaxy behind it in this 40 second exposure.

Also visible a few yards away was the setting crescent moon, with a planetary alignment to the west. Besides the moon, with it's dark side visible from earthshine, was brilliant Venus to the left, orange-tinted Mars at center top, and bright star Spica at center. All were setting in the west over the village of Sells, the capital of the Tohono O'Odham nation, within which the Observatory is located.

Another few yards from where we parked was still another view of the 4-meter telescope. A 90 second exposure showed the dome lit up by the Milky Way, and the glow of Tucson from the right. Visible to the left of the dome is the North Star Polaris, and to the right is Cassiopeia. Just after I opened the shutter, I spotted a flare from a satellite catching sunlight as it tumbled. Besides the bright flare, it came back into view a few seconds later and is visible in the image. An annotated image is again provided to point these out.

We finally finished off the photo-ops provided from the Steward 90" parking lot, so we headed down to a clearing partway down the mountain where we had planned to shoot the comet 103P/Hartley. We set up my 11" in the dark, and I quickly acquired it in the eastern sky (it is actually in Pegasus, in the Tucson lights shot above, but too faint to be seen). I had some issues with the telescope mount, and didn't get the exposure series I had hoped for, but one decent exposure showed it pretty well in a 3.5 minute exposure. It is quite extended and difficult to spot, but is supposed to get much brighter the next 2 months, approaching naked eye visibility!

I almost forgot to mention our rarest of sightings! When relocating a couple miles down the mountain, as we passed milepost 11, we spotted an animal heading into the grass. Melinda pointed and said "Coyote", but it had a long feline tail. I saw the rear haunches and tail of a mountain lion! I don't recall ever seeing one on the mountain in my hundreds, if not thousands of trips up to the Observatory, so it may have been my first. I've seen bobcats, ringtail cats, fox, deer, coyote and rattlesnakes, but no lions. They are not endangered, but they are so solitary they are seen rarely. Melinda was a bit spooked to be out alone afterwards, but I knew it was long gone and wouldn't bother us. But I was stoked to see one!

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