(meteorobs) Perseids and the Night Sky from Utah
Skywayinc at aol.com
Skywayinc at aol.com
Sun Aug 19 14:26:12 EDT 2007
Well . . . I have just returned from my two-week stint in the "Beehive
State" (Utah).
While I don't want to sound like George Costanza in the final episode of
Seinfeld (when he complained to Jerry about the quality of their private plane
flight to Paris), I was actually a little disappointed in the overall quality
of the night skies that I experienced in Utah. On my best night (Friday,
August 10), I estimated my limiting magnitude at the zenith at +6.8. On the
Bortle scale, this was somewhere between a 3 and 4 category. I could not see
M33 naked-eye, probably because of its low altitude. Our observing site was
in the parking field just outside of the visitor's center at Bryce Canyon.
This location, however, was only a few miles north of the Best Western/Ruby's
Inn (where we were staying) and the Inn's immediate surroundings are
brilliantly lit up. So even from three miles away, there was some semblance of a
faint light haze toward the north and northeast.
One of the park rangers (Kevin Poe) said that I would certainly find darker
skies if I traveled south about 15-miles to Rainbow Point, where the
elevation at the summit reaches to 9,115-feet. I passed on that, however, citing my
inexperience in negotiating a dark, unilluminated two-lane roadway in an
unfamiliar terrain. Kevin told me that from that location, however, airglow, the
zodiacal band and the gegenschein are readily visible. Perhaps I would have
seen a Bortle 2 or even a class 1 sky from Rainbow Point, but considering
that such sights were fairly common from areas 50-miles north of Midtown
Manhattan just 35-years ago, only demonstrates the extremes that one must go to
today just to get a view of a truly dark sky.
Being situated at an altitude of about 7,600-feet, I was impressed as to
how steady the seeing was. Except when right down near the horizon (as was the
case with, for example, Capella) the stars did not appear to twinkle or
scintillate at all. There were several large telescopes set up by the Bryce
rangers, and I was especially impressed by the views of the Great Globular Cluster
M13, as well as the open clusters M4, M6 and M7. The latter three are
objects that I do not see very often from home because of light haze and low
altitude, but from Bryce I had a dark sky backdrop and was positioned about
4-degrees farther south in latitude, so I took full advantage of these conditions.
We first saw the Perseids two nights before the predicted peak, coming at a
rate of of about one every three or four minutes. The most spectacular one
was an "Earth-grazer" of magnitude -6, appearing about an hour after sundown,
going straight down the Milky Way from Cygnus toward Scorpius. It left a
vapor trail that lasted about 3-seconds.
On the peak night (Sunday, August 12), the evening started out with a layer
of high cirroform covering much of the sky. The stars . . . and especially
Jupiter . . . all looked like fuzz-balls. I felt like the "Rao Curse" had
again followed me, this time all the way to Utah. Park ranger, Angie Richmond
started the evening off giving a very nice PowerPoint presentation for campers
on astronomy, then we all adjourned back to the parking field. Over the
span of the next several hours, the sky slowly cleared and when most of us
called it quits at around 3 a.m., it had become mainly clear. It was not as
transparent as Friday, however, and I estimated the LM at only around +6.4.
We saw several bright, slow-moving Earth-grazers . . . appearing mainly
below the Big Dipper and across Bootes . . . before midnight. Thereafter, we
settled into a pattern where we averaged a Perseid every minute or two. The
"clumping effect" was very noticeable, with two or three Perseids firing across
the sky, followed by a lull of several minutes before the sky "bore fruit"
once again. Most of the meteors appeared whitish, and about magnitude +2.
Very bright meteors seemed few and far between, although just before we packed
it in for the night, a dazzler of about -5 magnitude cut a nice path across
the Great Square and left a nice vapor trail for about five seconds.
I gave a talk about the Perseids to the campers, who numbered about 200 . .
. which gradually dwindled as the night wore on. I also spoke about light
pollution as I usually do at such gatherings (see below). I tried not to sound
"preachy" but I did tell the folks who were gathered around me that the
starry sky over their heads definitely should be considered on the "endangered"
list.
Overall, my family and I had a very good time although I came away feeling a
bit concerned because the Utah night skies . . . especially those on August
10 . . . were pretty much the kind of skies that were regularly available to
anyone who treked just a couple of hours north of New York City back in the
late 1970s (now, of course, no more).
I wondered what the night skies from Utah would look like in about 30-years?
Ranger Chad Moore, who heads the night sky team at Bryce, told me that all
lighting in the park would be swapped out for more efficient and full cut-off
fixtures in the coming year. But what concerns me is what happens outside
the boundaries of Bryce Canyon.
A big first step would be getting nearby Ruby's Inn to turn off a lot of its
lights, but I don't see that happening anytime soon.
Will Utah morph into the kind of night environment that the Northeast US has
evolved into during the next 30-years? Only time will tell.
-- joe rao
--------------------------------------------------------
From: _Chad_Moore at nps.gov_ (mailto:Chad_Moore at nps.gov) To: Joe Rao
(_jrao at news12.com_ (mailto:jrao at news12.com) ) Date: Tuesday - August 14,
2007 3:00 PM Subject: Re: Perseid Meteor Shower at Bryce Canyon Mime.822
(1996 bytes) Dear Joe,
Thank you very much for coming to Bryce. We enjoyed your company and
assistance. Glad
you got to meet some of our astronomy staff and see our excellent dark
skies. Keep in touch.
Chad Moore
NPS Night Sky Team
Bryce Canyon National Park
PO Box 640201
Bryce Canyon, UT 84764. USA.
435-834-4904
www2.nature.nps.gov/air/lightscapes
"There are certain values in our landscape that ought to be sustained
against destruction or impairment, though their worth cannot be expressed
in money terms. They are essential to our life, liberty, and pursuit of
happiness, this Nation of ours is not so rich it can afford to lose them,
it is still rich enough to afford to preserve them."
Newton B. Drury
Director NPS 1940-1951
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